JP2020139027A - Thermoplastic resin composition reduced in striking sound and molded article - Google Patents

Abstract

To provide a thermoplastic resin composition capable of providing a molded article which not only has high rigidity but also suppresses occurrence of striking sound and is also excellent in glossiness.SOLUTION: A thermoplastic resin composition is composed of at least a rubber-reinforced resin (A) having a rubbery part (a1) and a resin part (a2), in which the rubbery part (a1) contains a rubbery part (a1-1) derived from a block copolymer containing a block (I) having a structural unit derived from an aromatic vinyl-based compound and a block (II) that has isoprene or a structural unit derived from isoprene and butadiene and has a peak of main dispersion of tanδ at 0°C or higher or its hydrogenated product, the resin part (a2) contains a structural unit derived from an aromatic vinyl compound, and the thermoplastic resin composition further contains a heat aging inhibitor (B).SELECTED DRAWING: Figure 1

Description

The present invention relates to a thermoplastic resin composition which not only has high rigidity but also suppresses the generation of tapping sound and can provide a molded product having excellent gloss.

Rubber-reinforced resins such as ABS resin are widely used as molding materials for vehicle parts such as automobile interior parts due to their excellent mechanical properties, heat resistance, and moldability.

When molding a vehicle part with resin, it is possible not only to satisfy the mechanical strength above a certain level, but also to reduce the noise generated from the part and improve the quietness of the vehicle due to the comfort in the vehicle interior. More demanded.

Conventionally, by molding automobile interior parts with a rubber reinforced resin that uses an ethylene / α-olefin rubber polymer as a rubber component, it is generated by contact between parts while maintaining a certain level of mechanical strength. Although prevention of squeaking noise has already been performed (Patent Document 1), it has not been solved to suppress noise such as tapping noise called "rattle".

On the other hand, conventionally, by blending an elastomeric block polymer with a flame-retardant rubber reinforced resin and setting the loss coefficient at the secondary resonance frequency at 25 ° C. to 0.02 or more, vibration is suppressed and vibration damping is excellent. Although it has been proposed to obtain a flame-retardant resin composition (Patent Documents 2 to 4), no study has been made on suppressing noise such as tapping sound. On the other hand, by using a thermoplastic resin composition in which a polypropylene-based resin or a thermoplastic elastomer is blended in an AES resin in a predetermined amount as a tapping noise reducing material as a molding material, a molded product having reduced tapping noise while maintaining rigidity can be obtained. It is already known that this can be done (Patent Document 5).

Japanese Unexamined Patent Publication No. 2013-112812 Japanese Unexamined Patent Publication No. 2001-158841 JP-A-3-45646 Japanese Unexamined Patent Publication No. 8-3249 International Publication WO2018 / 03398

However, the present inventor has found that the resin composition of Patent Document 5 has a problem that the gloss of the molded product is lowered and the appearance of the molded product is deteriorated.
Therefore, an object of the present invention is a thermoplastic resin composition capable of providing a molded product in which the generation of tapping sound is suppressed, further maintaining good gloss of the molded product and exhibiting a good appearance of the molded product. It is to provide things.

As a result of diligent research to solve the above problems, the present inventor has a thermoplastic resin composition composed of at least a rubber-reinforced resin (A) containing a specific thermoplastic elastomer that functions as a tapping noise reducing material as a rubbery portion. We have found that by blending a heat-aging inhibitor into a product, not only the tapping sound is suppressed, but also a resin molded product having good gloss and excellent appearance can be obtained, and the present invention has been completed.

Thus, according to one aspect of the present invention, the thermoplastic resin composition is composed of at least a rubber-reinforced resin (A) having a rubbery portion (a1) and a resin portion (a2).
The rubbery portion (a1) includes a block (I) having a structural unit derived from an aromatic vinyl compound and a structural unit derived from isoprene or isoprene and butadiene, and has a main dispersion of tan δ at 0 ° C. or higher. It contains a rubbery moiety (a1-1) derived from a block copolymer containing a peaked block (II) or a hydrogenated product thereof.
The resin portion (a2) contains a structural unit derived from an aromatic vinyl compound and contains a structural unit.
As the thermoplastic resin composition, a thermoplastic resin composition containing a heat aging inhibitor (B) is further provided.

Further, according to another aspect of the present invention, a block (I) having a structural unit derived from an aromatic vinyl-based compound and a structural unit derived from isoprene or isoprene and butadiene are provided, and the temperature of tan δ is set to 0 ° C. or higher. A rubbery moiety (a1-1) derived from a block copolymer or a hydrogenated product thereof containing a block (II) having a main dispersion peak, and a resin moiety containing a structural unit derived from an aromatic vinyl-based compound (a resin moiety). Provided is a tapping noise reducing material for a thermoplastic resin composition, which is obtained by blending a heat aging inhibitor with a rubber reinforced resin (A1) having a2).

According to the present invention, a heat aging inhibitor is added to a thermoplastic resin composition composed of at least a rubber reinforced resin (A) containing a specific thermoplastic elastomer that functions as a tapping noise reducing material as a rubbery portion. As a result, it has become possible to obtain a resin molded product having a good appearance in which not only the tapping sound is suppressed but also the gloss of a certain level or more is maintained. Further, by blending the heat anti-aging agent, it is possible to prevent a decrease in the squeaking noise suppressing effect that occurs when the above-mentioned thermoplastic elastomer is blended in a certain amount or more. Since the thermoplastic elastomer that functions as a tapping noise reducing material constitutes the rubbery portion of the thermoplastic resin composition, the resin molded product thus obtained not only has acoustic characteristics in which tapping noise and squeaking noise are suppressed, but also has acoustic characteristics. It also has excellent mechanical strength such as rigidity. Thus, according to the present invention, there is provided a low-sounding article formed of the thermoplastic resin composition of the present invention. In particular, by forming at least the contact portion of the article including at least two parts that may intermittently contact each other due to vibration or the like with the thermoplastic resin composition of the present invention, tapping noise and squeaking noise are suppressed. It is possible to provide an article that has been silenced or muted.
In addition, the vibration damping property that has been studied in the past is related to the vibration that occurs continuously in the object when the object is continuously vibrated, whereas the tapping sound is the moment when another object collides with the object. It is related to the vibration that occurs, and the two have completely different times for absorbing and dispersing energy. In order to suppress the tapping sound, it is necessary to set the energy absorption and dispersion speed to an extremely instantaneous time. Further, the vibration damping property is different from each other in that the vibration noise generated by continuous vibration is a problem, while the tapping sound is a sound generated by a momentary impact.

It is a perspective view which shows the test piece used for measuring the tapping sound in this invention. It is a top view which shows the test piece used for the measurement of gloss in this invention, and the measurement position A and B of gloss.

Hereinafter, the present invention will be described in detail.
In the present invention, "(co) polymerization" means homopolymerization and / or copolymerization, "(meth) acrylic" means acrylic and / or methacrylic, and "(meth) acrylate" means. , Acrylic and / or methacrylate.
The melting point (sometimes referred to as "Tm" in the present specification) measured according to JIS K 7121-1987 is a constant temperature rise of 20 ° C. per minute using a DSC (Differential Scanning Calorimeter). It is a value obtained by measuring the endothermic change at a speed and reading the peak temperature of the obtained endothermic pattern.

1. 1. The thermoplastic resin composition (X) of the present invention
The thermoplastic resin composition of the present invention (also referred to as “component (X)” in the present specification) is a block copolymer or a block copolymer containing the above blocks (I) and blocks (II) as the rubbery portion (a1). It suffices to contain the rubber reinforced resin (A) having the rubbery portion (a1-1) derived from the hydrogen additive and the heat aging inhibitor, and only from the rubber reinforced resin (A) and the heat aging inhibitor. It may be configured or may further contain another thermoplastic resin (B).

The thermoplastic resin composition (X) of the present invention composed of only the rubber reinforced resin (A) and the heat aging inhibitor can be obtained, for example, by blending the rubber reinforced resin (A) with the heat aging inhibitor. Further, the thermoplastic resin composition (X) of the present invention, which comprises, in addition to the rubber reinforced resin (A) and the heat aging inhibitor, another thermoplastic resin (B), is, for example, a thermoplastic resin (B). ) By blending the rubber reinforced resin (A) and the heat aging inhibitor, or by blending the rubber reinforced resin (A) containing the heat aging inhibitor into the thermoplastic resin (B) as a tapping sound reducing material. Obtained by In this case, since the rubbery portion (a1-1) constituting the rubbery portion (a1) of the thermoplastic resin composition (X) is derived from the rubber reinforced resin (A), the tapping sound is produced. The effects of the present invention such as reduction can be achieved.
Examples of other thermoplastic resins (B) that can be blended in the thermoplastic resin composition (X) of the present invention include polycarbonate resins, polyamide resins, polyester resins, vinyl chloride resins, silicone resins, and polylactic acid resins. ..

Among the acoustic performances, from the viewpoint of suppressing tapping sound, the rubber reinforced resin (A) has a loss coefficient (η) in the frequency range of 20 to 12,400 Hz, especially when measured under the following conditions. The minimum value is preferably 0.02 or more, and more preferably 0.03 or more. Measurement condition:
Using a test piece prepared by cutting a flat plate with a thickness of 2 mm molded using an injection molding machine into a flat plate with a length of 250 mm, a width of 10 mm, and a thickness of 2 mm, by the central vibration method according to the provisions of JIS K 7244-1. Measured at a temperature of 23 ° C.

Further, similarly to the above, from the viewpoint of suppressing the tapping sound, the rubber reinforced resin (A) has a maximum sound pressure in the frequency range of 20 to 20,000 Hz, especially when measured under the following conditions. The value is preferably 3.0 Pa / N or less. The frequency that gives the maximum value of the sound pressure is preferably in the range of 20 to 9,000 Hz or 14,000 to 19,000 Hz. It is considered that the intensity of the tapping sound is suppressed as the maximum value of the sound pressure shifts to the lower frequency side within the range.
Measurement condition:
A test piece that is an integrally molded product having a trapezoidal protrusion with an upper base of 20 mm, a lower base of 40 mm, a height of 8 mm, and a thickness of 1.5 mm at the upper end of a rectangular body having a length of 120 mm, a width of 60 mm, and a thickness of 3 mm. With two threads attached to the protrusion with tape and suspended, the sound of hitting the center of one surface of the test piece with a stainless steel hammer with a force of 20 ± 5N is given to the surface. Measured based on the frequency spectrum of the sound pressure obtained by collecting sound with a sound pressure microphone installed 12 cm apart in the vertical direction.

Further, from the viewpoint of suppressing squeaking noise in the acoustic performance, the rubber reinforced resin (A) is particularly an abnormal noise measured by using a stick slip measuring device SSP-02 manufactured by ZIEGLER. It is preferable that the risk value shows 3 or less under the following measurement conditions.
Measurement condition:
Prepare a test piece with a length of 60 mm, a width of 100 mm, and a thickness of 4 mm, and a test piece with a length of 50 mm, a width of 25 mm, and a thickness of 4 mm, and load 5N, 40N, and speed 1 mm in an atmosphere of temperature 23 ° C. and humidity 50% RH. Measure the abnormal noise risk value when rubbing 3 times with an amplitude of 20 mm under 4 conditions of / sec and 10 mm / sec.
The abnormal noise risk value is a specification conforming to the German Automobile Manufacturers Association (VDA) standard, and indicates the risk of stick-slip abnormal noise when the contact members are made of the same material as an index of 10 levels. If the abnormal noise level is 3 or less, it is considered to be acceptable.

When not only the rubber-reinforced resin (A) contained in the thermoplastic resin composition (X) of the present invention but also the thermoplastic resin composition (X) of the present invention itself satisfies the above acoustic characteristics, it is acoustic. High quality molded products can be provided.

The thermoplastic resin composition (X) of the present invention is 100% by mass of the entire thermoplastic resin composition (X) from the viewpoint of mechanical properties such as impact resistance and acoustic properties such as tapping sound and squeak sound. The rubber content is preferably 5 to 60% by mass. Further, when the thermoplastic resin composition (X) has crystallinity or contains a component having crystallinity, the effect of suppressing the generation of squeak noise is more excellent and preferable. Specifically, the thermoplastic resin composition (X) preferably has a melting point in the range of 0 to 120 ° C., more preferably 10 to 90 ° C., as measured according to JIS K 7121-1987. The range of -80 ° C is even more preferable. As described above, the melting point (Tm) is obtained according to JIS K 7121-1987, but the number of peaks of the endothermic pattern in the range of 0 to 120 ° C. is not limited to one, and two or more. It may be. Further, the Tm (melting point) observed in the range of 0 to 120 ° C. may be derived from the rubber reinforced resin (A), particularly the rubbery portion, or is described below in relation to the rubber reinforced resin (A). The additive may be derived from a slidability-imparting agent such as a low molecular weight polyolefin wax having a number average molecular weight of 10,000 or less. The slidability imparting agent may be added to the rubber reinforced resin (A) or directly added to the thermoplastic resin composition (X).

The thermoplastic resin composition (X) of the present invention preferably retains high mechanical strength. Therefore, the thermoplastic resin composition (X) preferably has a bending modulus of 1,600 MPa or more, a deflection temperature under load (1.8 MPa) of 70 ° C. or higher, and a Rockwell hardness of 90 or higher. The tensile strength is preferably 35 MPa or more, and the bending strength is preferably 45 MPa or more. When the thermoplastic resin composition (X) is composed of only the rubber reinforced resin (A) and the heat aging inhibitor, the gloss of the molded product is 70 or more, and the MFR is 20 g / 10 min. The above is preferable. When the thermoplastic resin composition (X) is composed of the rubber reinforced resin (A), the polycarbonate resin and the heat aging inhibitor, the gloss of the molded product is preferably 80 or more, and the MFR is 40 g / 10 min. The above is preferable.

1-1. Rubber reinforced resin (A)
The rubber reinforced resin (A) has a rubbery portion (a1) derived from a rubbery polymer and a resin portion (a2) containing a structural unit derived from a vinyl-based monomer. It is preferable that a graft copolymer in which the resin portion (a2) is bonded to at least a part of the rubbery portion (a1) by graft polymerization or the like is formed. In other words, in the rubber reinforced resin (A), it is preferable that at least a part of the resin portion (a2) is bonded to at least a part of the rubbery portion (a1) by graft polymerization or the like. Therefore, the rubber reinforced resin is preferably composed of at least the above-mentioned graft copolymer and the (co) polymer constituting the resin portion (a2) which is not graft-polymerized on the rubbery portion (a1), and further. , The rubbery portion (a1) to which the resin portion (a2) is not grafted, or other components such as additives may be contained.

The rubber reinforced resin (A) is preferably crystalline because it further enhances the function of the thermoplastic resin composition (X) for suppressing the generation of abnormal noise such as a squeak noise. Specifically, the melting point of the thermoplastic resin composition (X) measured according to JIS K 7121-1987 is preferably in the range of 0 to 120 ° C, more preferably in the range of 10 to 90 ° C, 20 The range of -80 ° C is even more preferable.

1-2. Rubber part (a1) of rubber reinforced resin (A)
The rubbery portion (a1) may be a homopolymer or a copolymer as long as it is rubbery (has rubber elasticity) at 25 ° C. Further, the rubbery portion (a1) is composed of at least a rubbery portion (a1-1) derived from a block copolymer containing the block (I) and the block (II) or a hydrogenated product thereof. However, in addition to this, other rubbery parts derived from the rubbery polymer other than the block copolymer or its hydrogenated product may be provided. Examples of other rubbery portions include a rubbery portion (a1-2) derived from a non-diene polymer (hereinafter, "non-diene rubber") and a diene polymer (hereinafter, "diene rubber"). The rubbery portion (a1-3) derived from) can be mentioned. Further, these polymers may be crosslinked polymers or non-crosslinked polymers. Of these, in the present invention, at least a part of the rubbery portion (a1) may be composed of the rubbery portion (a1-3) from the viewpoint of improving mechanical strength such as impact resistance and rigidity. preferable. Further, from the viewpoint of the effect of suppressing abnormal noise such as tapping sound and squeaking sound, it is preferable that at least a part of the rubbery portion (a1) is composed of the rubbery portion (a1-2). It is more preferable that the portion (a1) is composed of the rubbery portion (a1-1) and the rubbery portion (a1-2). Further, the rubbery portion (a1) is replaced with the rubbery portion (a1-1) from the viewpoint of improving mechanical strength such as impact resistance and rigidity and suppressing abnormal noise such as tapping sound and squeaking noise. It is preferable that the rubbery portion (a1-2) is composed of the rubbery portion (a1-2) and the rubbery portion (a1-3).

1-2-1. Rubber part (a1-1)
The rubbery polymer constituting the rubbery portion (a1-1) includes a block (I) having a structural unit derived from an aromatic vinyl compound, and a structural unit derived from isoprene or isoprene and butadiene. A block copolymer containing a block (II) having a peak of the main dispersion of tan δ at 0 ° C. or higher or a hydrogenated product thereof is used.

Examples of the aromatic vinyl-based compound constituting the block (I) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, and vinyltoluene. , Vinyl xylene, vinyl naphthalene and the like. These compounds can be used alone or in combination of two or more. Of these, styrene and α-methylstyrene are preferable.

The peak of the main dispersion of tan δ in the block (II) needs to be 0 ° C. or higher, but is preferably 5 ° C. or higher, and more preferably 10 ° C. or higher. The peak of the main dispersion of tan δ was measured using a viscoelasticity measuring device [DDV III EP manufactured by Toyo Baldwin Co., Ltd.] at a frequency of 11 Hz, a measurement temperature of −110 ° C. to + 100 ° C., and a temperature rise rate of 2 ° C./min. Can be obtained. The 3,4 bond and 1,2 bond contents of the block (II) are preferably 40% or more, more preferably 50% or more, and even more preferably 60 to 98%.

The number average molecular weight of the block (I) is preferably 2500 to 40,000, more preferably 3500 to 35000, and even more preferably 4000 to 30000. The number average molecular weight of the block (II) is preferably 1000 to 20000, more preferably 20000 to 180,000, and even more preferably 2500 to 150,000. The total number average molecular weight of the block copolymer is preferably 30,000 to 300,000, more preferably 40,000 to 270000, and even more preferably 50,000 to 250,000.

1-2-2. Rubber part (a1-2)
The non-diene rubber constituting the rubbery portion (a1-2) is derived from ethylene / α-olefin rubber; urethane rubber; acrylic rubber; silicone rubber; silicone / acrylic IPN rubber; conjugated diene compound. Examples thereof include a hydrogenated polymer obtained by hydrogenating a (co) polymer containing a structural unit (however, the hydrogenation rate is 50% or more, excluding the block copolymer). This hydrogenated polymer may be a block copolymer or a random copolymer.

In the present invention, it is preferable to use an ethylene / α-olefin rubber as the non-diene rubber from the viewpoint of suppressing abnormal noise such as tapping sound and squeaking sound. The ethylene / α-olefin rubber is a copolymer rubber containing a structural unit derived from ethylene and a structural unit derived from α-olefin. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-. Eikosen and the like can be mentioned. These α-olefins can be used alone or in combination of two or more. From the viewpoint of impact resistance, the number of carbon atoms of the α-olefin is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 8. The mass ratio of ethylene: α-olefin in the ethylene / α-olefin rubber is usually 5 to 95:95 to 5, preferably 50 to 95:50 to 5, and more preferably 60 to 95:40 to 5. When the mass ratio of ethylene: α-olefin is in the above range, the impact resistance of the obtained molded product is further excellent, which is preferable. The ethylene / α-olefin rubber may contain a structural unit derived from a non-conjugated diene, if necessary. Examples of the non-conjugated diene include alkenylnorbornenes, cyclic dienes and aliphatic dienes, preferably 5-ethylidene-2-norbornene and dicyclopentadiene. These non-conjugated diene can be used alone or in admixture of two or more. The ratio of the structural unit derived from the non-conjugated diene to the whole non-diene rubber is usually 0 to 10% by mass, preferably 0 to 5% by mass, and more preferably 0 to 3% by mass.

In the present invention, it is preferable to use an ethylene / α-olefin rubber having a melting point (Tm) of 0 to 120 ° C. The Tm (melting point) of the ethylene / α-olefin rubber is more preferably 10 to 90 ° C, still more preferably 20 to 80 ° C. The fact that the ethylene / α-olefin rubber has a melting point (Tm) means that the rubber has crystallinity. Therefore, by using an ethylene / α-olefin rubber having such a melting point (Tm), the thermoplastic resin composition (X) can develop a melting point in the range of 0 to 120 ° C., and a tapping sound, a squeak sound, etc. The abnormal noise suppression effect of the above can be further improved. When the rubber reinforced resin (A) has such crystallinity, the occurrence of the stick-slip phenomenon is suppressed. Therefore, when the molded product and another article dynamically come into contact with each other, abnormal noise such as a squeak noise is generated. It is thought to be suppressed. The stick-slip phenomenon is disclosed in Japanese Patent Application Laid-Open No. 2011-174029 and the like.

The Mooney viscosity (ML1 + 4, 100 ° C.; conforming to JIS K 630-1) of the ethylene / α-olefin rubber is usually 5 to 80, preferably 10 to 65, and more preferably 10 to 45. When the Mooney viscosity is in the above range, the moldability is excellent, and the impact strength and appearance of the molded product are further excellent, which is preferable.

The ethylene / α-olefin rubber is preferably an ethylene / α-olefin copolymer containing no non-conjugated diene component from the viewpoint of reducing the generation of abnormal noise such as tapping sound and squeaking noise. Among these, ethylene / propylene is preferable. Copolymers, ethylene / 1-butene copolymers, ethylene / 1-octene copolymers are more preferable, and ethylene / propylene copolymers are particularly preferable.

1-2-3. Rubber part (a1-3)
Examples of the diene-based rubber constituting the rubbery portion (a1-3) include homopolymers such as polybutadiene and polyisoprene; styrene / butadiene copolymer, styrene / butadiene / styrene copolymer, and acrylonitrile / styrene / butadiene co-weight. Combined, butadiene-based copolymers such as acrylonitrile / butadiene copolymers; isoprene-based copolymers such as styrene / isoprene copolymers, styrene / isoprene / styrene copolymers, acrylonitrile / styrene / isoprene copolymers, etc. Be done. These may be random copolymers or block copolymers. These can be used alone or in combination of two or more. The diene-based rubbery polymer may be a crosslinked polymer or an uncrosslinked polymer.

1-2-4. Composition of Rubbery Part (a1) In the present invention, the content of the rubbery part (a1) in the rubber reinforced resin (A), that is, the rubber content is preferably 100% by mass based on the total mass of the rubber reinforced resin (A). It is 3 to 80% by mass, more preferably 3 to 75% by mass, still more preferably 4 to 70% by mass, still more preferably 5 to 70% by mass, and particularly preferably 7 to 65% by mass. When the rubber content is within the above range, the thermoplastic resin composition (X) is more preferably excellent in impact resistance, effect of reducing abnormal noise such as tapping sound and squeaking sound, dimensional stability, and moldability.

When the rubbery portion (a1) is composed of two types, the rubbery portion (a1-1) and the rubbery portion (a1-2), the rubbery portion (a1) is the rubbery portion (a1-). 1) It is preferably composed of 1 to 15% by mass and 2 to 12% by mass of the rubbery portion (a1-2), and 3 to 14% by mass of the rubbery portion (a1-1) and the above. It is more preferable that the rubbery portion (a1-2) is composed of 4 to 10% by mass (however, the total of the thermoplastic resin composition (X) is 100% by mass).
When the rubbery portion (a1) is composed of three types of the rubbery portion (a1-1), the rubbery portion (a1-2) and the rubbery portion (a1-3), the rubbery portion (a1) ) Consists of 1 to 15% by mass of the rubbery portion (a1-1), 2 to 12% by mass of the rubbery portion (a1-2), and 3 to 10% by mass of the rubbery portion (a1-3). The rubbery portion (a1-1) is preferably 3 to 14% by mass, the rubbery portion (a1-2) is 4 to 10% by mass, and the rubbery portion (a1-3) is 4 to 9% by mass. It is more preferable that it is composed of% (however, the total of the thermoplastic resin composition (X) is 100% by mass).

1-3. Resin portion (a2) of rubber reinforced resin (A)
The resin portion (a2) of the rubber reinforced resin (A) is composed of a structural unit derived from a vinyl-based monomer, contains an aromatic vinyl compound as an essential component, and is copolymerized with the aromatic vinyl compound and the aromatic vinyl compound. It may be composed of possible compounds. Specific examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyltoluene, vinylxylene, and vinyl. Naphthalene and the like can be mentioned. These compounds can be used alone or in combination of two or more. Of these, styrene and α-methylstyrene are preferable.

As the compound copolymerizable with the aromatic vinyl compound, at least one selected from a vinyl cyanide compound and a (meth) acrylic acid ester compound can be preferably used, and if necessary, co-polymerized with these compounds. Other polymerizable vinyl-based monomers can also be used. Examples of such vinyl-based monomers include maleimide-based compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds, hydroxyl group-containing unsaturated compounds, oxazoline group-containing unsaturated compounds, and epoxy group-containing unsaturated compounds. These can be used alone or in combination of two or more.

Specific examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, etacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile and the like. These compounds can be used alone or in combination of two or more. Of these, acrylonitrile is preferred.

Specific examples of the above (meth) acrylic acid ester compound include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, n-propyl (meth) acrylic acid, isopropyl (meth) acrylic acid, and n (meth) acrylic acid. -Butyl, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, n-octyl (meth) acrylate, 2 (meth) acrylate -Ethylhexyl, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate and the like can be mentioned. These compounds can be used alone or in combination of two or more. Of these, methyl methacrylate is preferable.

Specific examples of the maleimide-based compound include N-phenylmaleimide and N-cyclohexylmaleimide. These compounds can be used alone or in combination of two or more.

Specific examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride and the like. These compounds can be used alone or in combination of two or more.

Specific examples of the above-mentioned carboxyl group-containing unsaturated compound include (meth) acrylic acid, etacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, and cinnamic acid. These compounds can be used alone or in combination of two or more.

Specific examples of the above hydroxyl group-containing unsaturated compound include 3-hydroxy-1-propene, 4-hydroxy-1-butene, cis-4-hydroxy-2-butene, trans-4-hydroxy-2-butene, and 3 Examples thereof include −hydroxy-2-methyl-1-propene, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate. These compounds can be used alone or in combination of two or more.

The lower limit of the content of the structural unit derived from the aromatic vinyl compound in the rubber reinforced resin (A) is derived from the structural unit derived from the aromatic vinyl compound and the compound copolymerizable with the aromatic vinyl compound. When the total of the structural units is 100% by mass, it is preferably 40% by mass, more preferably 50% by mass, and further preferably 60% by mass. The upper limit is usually 100% by mass.

When the rubber reinforced resin resin portion (a2) contains a structural unit derived from an aromatic vinyl compound and a vinyl cyanide compound as a structural unit, the content of the structural unit derived from the aromatic vinyl compound is 100 in total. When it is set to mass%, it is usually 40 to 90% by mass, preferably 55 to 85% by mass, and the content of the structural unit derived from the vinyl cyanide compound is 100% by mass in total. In addition, it is 10 to 60% by mass, preferably 15 to 45% by mass.

1-4. Method of manufacturing rubber reinforced resin (A) As a method of manufacturing rubber reinforced resin (A), when the rubbery portion (a1) is composed of only the rubbery portion (a1-1), for example, the rubbery portion. (A1-1) itself is melt-kneaded with the resin portion (a2), or the vinyl constituting the resin portion (a2) in the presence of the rubbery polymer constituting the rubbery portion (a1-1). Examples thereof include a method of graft-polymerizing a system monomer (the rubber reinforced resin obtained by these methods is referred to as "first rubber reinforced resin" or "rubber reinforced resin (A1)" in the present specification).

Further, the rubbery portion (a1) is composed of other rubbery parts such as the rubbery part (a1-2) and the rubbery part (a1-3) in addition to the rubbery part (a1-1). In this case, as a method for producing the rubber reinforced resin (A), for example, a vinyl-based single amount constituting the resin portion (a2) in the presence of the rubber polymer constituting the rubbery portion (a1-2). A second rubber-reinforced resin (also referred to as "rubber-reinforced resin (A2)" in the present specification) obtained by a method of graft-polymerizing a body, and a rubber polymer constituting the rubbery portion (a1-3). A third rubber-reinforced resin (also referred to as "rubber-reinforced resin (A3)" in the present specification) obtained by a method of graft-polymerizing a vinyl-based monomer constituting the resin portion (a2) in the presence of Or, in the presence of two types of rubbery polymers constituting each of the rubbery portion (a1-2) and the rubbery portion (a1-3), a vinyl-based single amount constituting the resin portion (a2). A fourth rubber reinforced resin obtained by a method of graft-polymerizing a body is produced, and at least one selected from the second, third and fourth rubber reinforced resins and the first rubber reinforced resin are melted. There is a method of kneading.
In the case of producing by graft-polymerizing the first, second, third and fourth rubber reinforced resins, the polymerization method is not particularly limited as long as the graft copolymer can be obtained, and a known method shall be applied. Can be done. The polymerization method can be emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, or a polymerization method in which these are combined. In these polymerization methods, known polymerization initiators, chain transfer agents (molecular weight modifiers), emulsifiers and the like can be appropriately used.

In the above production method in which graft polymerization is carried out, usually, a graft copolymer in which a (co) polymer of vinyl-based monomers is graft-polymerized to a rubber polymer and a vinyl-based polymer in which the (co) polymer is not graft-polymerized to a rubber polymer A mixed product of monomers with a (co) polymer is obtained. In some cases, the mixed product may include a rubbery polymer in which the (co) polymer has not been graft-polymerized. The rubber reinforced resin (A) is composed of a rubbery portion (a1) derived from a rubbery polymer and a resin portion (a2) having a structural unit derived from a vinyl-based monomer, and the rubbery portion (a1) is Since it is preferable that the resin portion (a2) forms a graft-polymerized graft copolymer, a mixed product of the graft-copolymer produced as described above and the (co-) polymer can be used as described above. It can be used as it is as the first, second, third and fourth rubber reinforced resins.

The rubber reinforced resin (A) is obtained by adding a (co) polymer (A') produced by polymerizing a vinyl-based monomer in the absence of the rubbery polymer (a). May be good. When this (co) polymer (A') is added to the rubber reinforced resin (A), it constitutes a resin portion (a2) that is not graft-polymerized on the rubbery portion (a1).

The graft ratio of the rubber reinforced resin (A) is usually 10 to 150%, preferably 15 to 120, in any of the above-mentioned first, second, third and fourth rubber reinforced resins obtained by graft polymerization. %, More preferably 20 to 100%, particularly preferably 20 to 80%. When the graft ratio of the rubber reinforced resin (A) is within the above range, the impact resistance of the molded product of the present invention is further improved.

The graft ratio can be calculated by the following mathematical formula (1).
Graft ratio (mass%) = ((ST) / T) x 100 ... (1)
In the above formula, for S, 1 gram of rubber reinforced resin (A) was added to 20 ml of acetone, shaken for 2 hours by a shaker under a temperature condition of 25 ° C., and then centrifuged under a temperature condition of 5 ° C. It is the mass (g) of the insoluble matter obtained by centrifuging with a machine (rotation speed; 23,000 rpm) for 60 minutes and separating the insoluble matter and the soluble matter, and T is 1 gram of the rubber reinforced resin (A). It is the mass (g) of the rubbery part (a1) contained. The mass of the rubbery portion (a1) can be obtained by infrared spectroscopic analysis, pyrolysis gas chromatography, CHN elemental analysis, etc., in addition to the method of calculating from the polymerization formulation and the polymerization conversion rate.

The graft ratio is, for example, the type and amount of the chain transfer agent used in the graft polymerization in producing the rubber reinforced resin (A), the type and amount of the polymerization initiator, and the method and addition of the monomer component at the time of polymerization. It can be adjusted by appropriately selecting the time, polymerization temperature and the like.

The ultimate viscosity (30 ° C. in methyl ethyl ketone) of the acetone-soluble component (hereinafter, also referred to as “acetone-soluble component”) of the rubber-reinforced resin (A) in the thermoplastic resin composition of the present invention is usually 0.05. It is ~ 0.9 dl / g, preferably 0.07 to 0.8 dl / g, and more preferably 0.1 to 0.7 dl / g. When the ultimate viscosity is in the above range, the impact resistance and moldability of the resin composition become better.

The ultimate viscosity [η] can be measured by the following method. First, the acetone-soluble component of the rubber reinforced resin (A) was dissolved in methyl ethyl ketone to prepare 5 points having different concentrations. The ultimate viscosity [η] was determined from the results of measuring the reduced viscosity of each concentration at 30 ° C. using an Ubbelohde viscous tube. The unit is dl / g.

The ultimate viscosity [η] is, for example, the type and amount of the chain transfer agent used when graft-polymerizing the rubber reinforced resin (A), the type and amount of the polymerization initiator, and the method of adding the monomer component at the time of polymerization. And it can be adjusted by appropriately selecting the addition time, the polymerization temperature, the polymerization time and the like. Further, the rubber reinforced resin (A) can be adjusted by mixing a (co) polymer (A') having an intrinsic viscosity [η] different from the intrinsic viscosity [η] of the acetone-soluble component.

The rubber reinforced resin (A) may contain a slidability imparting agent and other additives. The slidability-imparting agent imparts slidability to the thermoplastic resin composition (X), facilitating the assembly of an article made of a molded product obtained from the thermoplastic resin composition (X) of the present invention. Not only that, it is possible to impart the effect of suppressing the generation of abnormal noise such as squeaking noise from the article made of the molded product during use. Typical examples of the slidability-imparting agent include low molecular weight polyethylene oxide (c1), ultra high molecular weight polyethylene (c2), polytetrafluoroethylene (c3), and low molecular weight polyethylene oxide (c1) as described in JP-A-2011-137066. Examples thereof include polyolefin wax and silicone oil having a molecular weight (for example, a number average molecular weight of 10,000 or less).

As the polyolefin wax, polyethylene wax having a melting point of 0 to 120 ° C. or the like is preferable. Further, when a polyolefin wax having such a melting point or another additive having a melting point of 0 to 120 ° C. is added to the rubber reinforced resin (A), the rubbery portion of the rubber reinforced resin (A) becomes the melting point ( Even if Tm) is not provided, the effect of suppressing the generation of abnormal noise such as squeaking noise can be obtained. These slidability imparting agents may be used alone or in combination of two or more. The blending amount of these slidability-imparting agents is usually 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber reinforced resin (A).

Other additives include antioxidants, UV absorbers, weather resistant agents, fillers, antistatic agents, flame retardant agents, antifogging agents, lubricants, antibacterial agents, fungicides, tackifiers, etc. Examples thereof include plasticizers, colorants, graphite, carbon black, carbon nanotubes, pigments (for example, pigments having an ultraviolet absorbing and reflecting ability and imparting functionality) and the like. These may be used alone or in combination of two or more. The blending amount of these additives is usually 0.1 to 30 parts by mass with respect to 100 parts by mass of the rubber reinforced resin (A).

A thermoplastic resin composition obtained by blending a heat aging inhibitor with a rubber reinforced resin (A) (first rubber reinforced resin) in which the rubbery portion (a1) is composed of only the rubbery portion (a1-1). It is used as a tapping sound reducing material used by blending with another rubber reinforced resin or another thermoplastic resin (B) other than the rubber reinforced resin in order to suppress tapping sound.
In the thermoplastic resin composition (X) of the present invention, the amount of the first rubber reinforced resin that functions as a tapping noise reducing material is 100% by mass, preferably 0.1, based on the entire thermoplastic resin composition (X). It is ~ 40% by mass, more preferably 1 to 35% by mass. When the amount of the rubber-reinforced aromatic vinyl resin (A1) used is within the above range, the balance between the effect of reducing the tapping sound of the molded product and the mechanical strength is improved. The content of the rubbery portion (a1-1) is 3 to 25% by mass, preferably 7.5 to 20% by mass, with the entire thermoplastic resin composition (X) as 100% by mass. When the content of the rubbery portion (a1-1) is 7.5% by mass or more, the effect of suppressing the tapping sound is improved, while the effect of suppressing the squeaking sound tends to decrease. By adding the anti-aging agent, it is possible to prevent the squeaking noise from being suppressed from being lowered. Therefore, according to the present invention, the tapping sound can be highly suppressed and the squeaking noise can also be suppressed.

2. 2. Thermal Anti-Aging Agent The thermal anti-aging agent used in the present invention is not particularly limited as long as it is a thermal anti-aging agent contained in rubber or the like, but a phenol-based antioxidant and a phosphorus-based antioxidant are preferable.
Examples of the phenolic antioxidant include a phenolic antioxidant having a phenol group having a t-butyl group at the ortho position as represented by the following general formula (I).

In the formula, R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and t-Bu represents a t-butyl group.

In the above general formula (I), the substituents R ¹ and R ² are preferably hydrogen atoms, t-butyl groups or methyl groups, respectively, and more preferably hydrogen atoms or methyl groups, in particular. , R ¹ is particularly preferably a hydrogen atom. Specifically, the phenolic antioxidant used in the present invention is preferably a compound having one or more groups represented by the general formula (I), and the following formulas (C1), (C2) and It is more preferable that the compound is represented by any one of (C3).

Examples of the phosphorus-based antioxidant include compounds represented by the following general formula (II).

In the formula, R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Particularly preferably, R ³ and R ⁴ are t-C ₄ H ₉ units.

In the present invention, the amount of the heat antiaging agent to be blended is preferably 0.01 to 5 parts by weight, more preferably 0.02 to 3 parts by weight, when the thermoplastic resin composition (X) is 100 parts by weight. Even more preferably, it is 0.03 to 2 parts by weight, particularly preferably 0.03 to 1 part by weight, and the most preferable ranges are 0.02 to 0.6 parts by weight and 0.02 to 0.2 parts by weight. Examples thereof include parts by weight, 0.03 to 0.6 parts by weight, or 0.03 to 0.2 parts by weight. When the blending amount is within the above range, the gloss of the molded product is excellent, a good appearance can be obtained, and when the content of the rubbery portion (a1-1) is 4.0% by mass or more, squeaking noise is suppressed. The effect is also obtained.

3. 3. Method for Producing Thermoplastic Resin Composition (X) of the Present Invention In the thermoplastic resin composition (X) of the present invention, each component is mixed in a predetermined compounding ratio with a tumbler mixer, a Henschel mixer, or the like, and then a uniaxial extruder is used. , It can be produced by melt-kneading under appropriate conditions using a kneader such as a twin-screw extruder, a Banbury mixer, a kneader, a roll, or a feeder ruder. A preferred kneader is a twin-screw extruder. Further, when kneading each component, the components may be kneaded all at once, or may be kneaded in multiple stages and divided. After kneading with a Banbury mixer, a kneader, etc., it can be pelletized with an extruder. The melt-kneading temperature is usually 180 to 240 ° C, preferably 190 to 230 ° C.

4. Method for Producing Molded Product of the Present Invention The molded product of the present invention is an injection molding, gas injection molding, press molding, sheet extrusion molding, vacuum molding, deformed extrusion molding, foam molding, material extrusion of a thermoplastic resin composition (X). It can be manufactured by molding by a known molding method such as a deposition method or powder sintered laminated molding.
Since the thermoplastic resin composition (X) of the present invention has the above-mentioned excellent properties, it can be used for vehicle interior products and exterior products. For example, seat belt buckle, upper box, cup holder, door trim, door knob, door pocket, door lining, pillar garnish, console, console box, room mirror, sun visor, center panel, ventilator, air conditioner, air conditioner panel, heater control panel. , Plate blade, valve shutter, louver, etc., duct, meter panel, meter case, meter visor, instrument panel upper garnish, instrument panel lower garnish, A / T indicator, "on / off switches (slide part, slide plate), switch bezel, Masks (mask switch, mask radio, etc.) such as grill front defroster, grill side defroster, lid cluster, cover instroer, pockets (pocket deck, pocket card, etc.), steering wheel horn pad, cup holder, switch parts, switch Grips such as boxes and assist grips, handles, grab handles Car navigation exterior parts, camera covers, camera monitoring systems, head-up displays, rear entertainment systems, glove boxes, glove box ratchets, accessory cases, accessory cases, etc. Vehicle interiors such as ratchet, room mirror, room lamp, armrest, speaker grill, navigation panel, overhead console, clock indicator, SOS switch, front grill, wheel cap, bumper, fender, spoiler, garnish, door mirror, radiator grill, rear Vehicle exterior parts such as combination lamps, head lamps, turn lamps, grips on outside door handles, office equipment, cases for household appliances, exterior parts such as housings, interior parts, parts around switches, moving parts, Lock parts for desks, desk drawers, paper trays for copying machines, straight tube type LED lamps, light bulb type LED lamps, light bulb type fluorescent lights, ceiling light panels, covers, connectors and other lighting equipment, mobile phones, tablet terminals, rice cooking Vessels, refrigerators, microwave ovens, gas stoves, vacuum cleaners, dishwashers, air purifiers, air conditioners, heaters, TVs, recorders and other home appliances, printers, fax machines, copiers, personal computers, projectors and other OA equipment, audio equipment, Sound equipment such as organs and electronic pianos, caps for cosmetic containers , Can be used as a battery cell housing, etc., and can be particularly preferably used as a vehicle interior product.

Further, the molded product of the present invention may be composed of one part or two or more parts, but two parts that may come into contact with each other are used. At least, it can be suitably used as a part of an article that has a risk of generating a tapping sound when both parts come into contact with each other. According to the present invention, for example, at least two parts that may come into contact with each other are provided, and at least a part of a part of the other part that may come into contact with at least one part of the two parts is heated. An article formed of the thermoplastic resin composition (X) can be provided. In other words, according to the present invention, there are at least a first component and a second component that may come into contact with each other, and the first component may come into contact with the second component. An article in which at least a part of the portion is formed of the thermoplastic resin composition (X) can be provided. In this case, it is preferable that the whole of the first part or a part or all of the portion in contact with the second part is formed of the thermoplastic resin composition (X).
The second part with which the first part comes into contact may be a part molded with the thermoplastic resin composition (X), or a resin other than the thermoplastic resin composition (X). It may be a part molded in or made of another material such as metal. Examples of the resin other than the thermoplastic resin composition (X) include a polypropylene resin, a rubber-reinforced aromatic vinyl resin such as ABS resin, an acrylic resin such as polymethylmethacrylate, a polycarbonate resin, a polycarbonate / ABS alloy, and a nylon resin. Examples thereof include nylon / ABS alloy, PET resin, PET / ABS alloy, PBT / ABS alloy, thermoplastic elastomer, and thermosetting elastomer.

As the above-mentioned article having at least the first part and the second part which may come into contact with each other, if the first and second parts have the possibility of coming into contact with each other as described above. Although not particularly limited, for example, an article in which the first and second parts are adjacent to each other with a gap but intermittently come into contact with each other due to an external force such as vibration or opening / closing operation, more specifically, both parts are attached to each other. Examples include loose fit, that is, loosely fitted articles. The method of fitting the two parts is not particularly limited as long as the two parts are loosely fitted, and may be, for example, snap fit, screwing, or engagement. Examples of such an article include an article provided with an opening / closing part (for example, a lid, a door) configured in a push-open manner using a push latch or a magnet latch, and more specifically, a vehicle interior part. Then, opening and closing parts such as sunglasses trays can be mentioned.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. In the examples, parts and% are based on mass unless otherwise specified.
1. 1. Raw material [P]
As the rubber-reinforced aromatic vinyl resin, the rubber-reinforced aromatic vinyl resin obtained in Synthesis Examples 1 and 2 below was used.

1-1. Synthesis Example 1 (Synthesis of raw material P1 (diene-based rubber-reinforced aromatic vinyl-based resin))
In a polymerization vessel with a stirrer, 280 parts of water and 60 parts of polybutadiene latex (solid content equivalent) with a weight average particle diameter of 0.26 μm and a gel content of 90% as a diene-based rubbery polymer, sodium formaldehyde styrene xylate 0.3 Parts, 0.0025 parts of ferrous sulfate and 0.01 parts of disodium ethylenediamine tetraacetate were charged, deoxidized, heated to 60 ° C. with stirring in a nitrogen stream, and then 10 parts of acrylonitrile, 30 parts of styrene, t. -A monomer mixture consisting of 0.2 parts of dodecyl mercaptan and 0.3 parts of cumene hydroperoxide was continuously added dropwise at 60 ° C. over 5 hours. After completion of the dropping, the polymerization temperature was adjusted to 65 ° C., stirring was continued for 1 hour, and then the polymerization was terminated to obtain a latex of a graft copolymer. The polymerization conversion rate was 98%. Then, 0.2 part of 2,2'-methylene-bis (4-ethylene-6-t-butylphenol) was added to the obtained latex, calcium chloride was added to coagulate, and washing, filtration and drying steps were performed. To obtain a powdery resin composition. The graft ratio of the obtained resin composition was 40%, and the ultimate viscosity [η] of the acetone-soluble component was 0.38 dl / g.

1-2. Synthesis Example 2 (Synthesis of raw material P2 (ethylene / propylene (EP) rubber-reinforced aromatic vinyl resin))
An ethylene / propylene copolymer (ethylene / propylene = 78) as an ethylene / α-olefin rubber polymer in a 20-liter stainless steel autoclave equipped with a ribbon-type stirrer blade, a continuous additive addition device, a thermometer, etc. / 22 (%), Mooney viscosity (ML1 + 4, 100 ° C) 20, melting point (Tm) 40 ° C, glass transition temperature (Tg) -50 ° C) 22 parts, styrene 55 parts, acrylonitrile 23 parts, t- 0.5 part of dodecyl mercaptan and 110 parts of toluene were charged, the internal temperature was raised to 75 ° C., and the contents of the autoclave were stirred for 1 hour to prepare a uniform solution. Then, 0.45 parts of t-butylperoxyisopropyl monocarbonate was added to further raise the internal temperature, and after reaching 100 ° C., the polymerization reaction was carried out at a stirring rotation speed of 100 rpm while maintaining this temperature. went. From the 4th hour after the start of the polymerization reaction, the internal temperature was raised to 120 ° C., and the reaction was carried out for another 2 hours while maintaining this temperature to complete the polymerization reaction. Then, the internal temperature was cooled to 100 ° C., octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenol) -propionate 0.2 part, dimethyl silicone oil; KF-96-100cSt (trade name). : After adding 0.02 part of Shinetsu Silicone Co., Ltd., the reaction mixture was extracted from the autoclave, the unreacted product and the solvent were distilled off by steam distillation, and an extruder with a 40 mmφ vent (cylinder temperature 220 ° C., degree of vacuum) was added. 760 mmHg) was used to substantially degas the volatiles and pelletize. The obtained ethylene / α-olefin rubber-reinforced vinyl resin had a graft ratio of 70% and an acetone-soluble component having an ultimate viscosity [η] of 0.47 dl / g.

2. 2. Raw material [Q]
The following raw material Q1 was used as the thermoplastic resin containing no portion derived from the rubbery polymer.

2-1. Raw material Q1 (AS resin)
An acrylonitrile-styrene copolymer having an acrylonitrile unit and a styrene unit ratio of 27% and 73%, respectively, and an ultimate viscosity [η] (30 ° C. in methyl ethyl ketone) of 0.47 dl / g. The glass transition temperature (Tg) was 103 ° C.

2-2. Synthesis Example 3 (Synthesis of raw material Q2 (heat resistant AS resin))
250 parts of water and 1.0 part of sodium palmitate were put into a polymerization vessel equipped with a stirrer, and after deoxidation, the mixture was heated to 70 ° C. with stirring in a nitrogen stream. Further, after charging 0.4 parts of sodium formaldehyde sulfoxylate, 0.0025 parts of ferrous sulfate and 0.01 parts of disodium ethylenediamine tetraacetate, 70 parts of α-methylstyrene, 25 parts of acrylonitrile, 5 parts of styrene, t- A monomer mixture consisting of 0.5 part of dodecyl mercaptan and 0.2 part of cumene hydroperoxide was continuously added dropwise at a polymerization temperature of 70 ° C. over 7 hours. After completion of the dropping, the polymerization temperature was adjusted to 75 ° C., and stirring was continued for 1 hour to terminate the polymerization, and a latex of a copolymer was obtained. The polymerization conversion rate was 99%. Then, the obtained latex was coagulated by adding calcium chloride, and a powdery copolymer was obtained through washing, filtration and drying steps. The ultimate viscosity [η] of the acetone-soluble component of the obtained copolymer was 0.40 dl / g.

3. 3. Raw material [R]
3-1. Raw material R1 (thermoplastic elastomer)
Styrene-isoprene-styrene (SIS) block copolymer "Hybler 5127" (trade name, manufactured by Kuraray Co., Ltd., styrene content 20%, glass transition temperature (Tg) 8 ° C., peak temperature of tan δ main dispersion 25 ° C., 3, 4 bond and 1 and 2 bond content 95%) were used.

4. Raw material [S]
4-1. Raw material S1 (heat anti-aging agent)
Phenolic heat anti-aging agent "Sumilyzer GS" (trade name; manufactured by Sumitomo Chemical Co., Ltd., 1'-hydroxy acrylate [2,2'-ethylidenebis [4,6-bis (1,1-dimethylpropyl) benzene]] ] -1-Il) was used.

5. Raw material [T]
5-1. Raw material T1 (PC resin)
Polycarbonate resin "NOVAREX 7022J (trade name)" manufactured by Mitsubishi Engineering Plastics Co., Ltd. was used.

Examples 1-10 and Comparative Examples 1-4
1. 1. Preparation of Thermoplastic Resin Composition The raw materials [P], [Q], [R], [S] and [T] shown in Table 1 or Table 2 were mixed in the blending ratios shown in the same table. Then, using a twin-screw extruder (model name "TEX44, Japan Steel Works"), melt-kneading was performed at 250 ° C. to pelletize. The obtained resin composition was used for the following measurements and evaluations. The results are shown in Table 1 below.

2. 2. Bending modulus (rigidity)
Measured according to ISO178

3. 3. Measured under 1.8 MPa load conditions according to the deflection temperature ISO75

4. Measured according to Rockwell hardness ISO2039

5. Measured according to tensile strength ISO527

6. Bending strength measured according to ISO178

7. Sound pressure measurement of tapping sound Using each thermoplastic resin composition, upper bottom 20 mm, lower bottom 40 mm, height 8 mm, thickness at the upper end of a rectangular body of 120 mm in length, 60 mm in width, and 3 mm in thickness as shown in FIG. A test piece, which is an integrally molded product with a 1.5 mm trapezoidal protrusion, is injection molded by Toshiba Machine's IS-170FA injection molding machine at a cylinder temperature of 250 ° C, an injection pressure of 50 MPa, and a mold temperature of 60 ° C. did. Then, with two threads attached to the protrusions of the test piece with tape and suspended, the center of one surface of the test piece is made of stainless steel manufactured by PCB Piezotronics, which can measure the striking force. A sound pressure microphone (trade name: 378B02) manufactured by PCB Piezotronics, which is installed 12 cm away from the surface in the direction perpendicular to the surface when hit with a force of 20 ± 5N using a hammer (trade name: 086C03). ), And converted into a sound pressure frequency spectrum with a Fourier transform analyzer (trade name: MultiJOB FFT Analyzer OR34J-4) manufactured by Oros. The maximum value of sound pressure (Pa / N) in the obtained frequency spectrum and its frequency (Hz) were used as measured values. The measurement was performed in a room at room temperature of 23 ° C. The sound pressure (Pa / N) obtained as a measured value means the sound pressure per 1 N of the measured striking force.

8. Attenuation of tapping sound The same operation as the sound pressure measurement of the tapping sound was performed, and the time change of the sound pressure was measured with a Fourier transform analyzer (trade name: MultiJOB FFT analyzer OR34J-4) manufactured by Oros. The time required from the generation of the sound until the sound pressure settled down to 1/4 of the maximum sound pressure was used as the attenuation time of the tapping sound. The attenuation of the tapping sound is preferably shorter than 0.01 seconds, and more preferably shorter than 0.008 seconds.

9. Loss coefficient A test piece prepared by cutting a flat plate with a thickness of 2 mm molded using an injection molding machine to a length of 250 mm, a width of 10 mm, and a thickness of 2 mm is used, and central excitation is performed in accordance with JIS K 7244-1. It was measured at a temperature of 23 ° C. by the method, and the minimum value of the loss coefficient (η) in the frequency range of 20 to 12,400 Hz was defined as the loss coefficient.

10. MFR
The melt mass flow rate was measured under the conditions of a temperature of 240 degrees and a load of 98 N according to ISO1133.

11. Squeak sound evaluation (abnormal noise risk value)
Each thermoplastic resin composition is injection-molded by Toshiba Machine's IS-170FA injection molding machine at a cylinder temperature of 250 ° C., an injection pressure of 50 MPa, and a mold temperature of 60 ° C., and an injection-molded plate having a length of 150 mm, a width of 100 mm, and a thickness of 4 mm. Got From this plate, a test piece having a length of 60 mm, a width of 100 mm, a thickness of 4 mm, a length of 50 mm, a width of 25 mm, and a thickness of 4 mm is cut out with a disk saw, the end is chamfered with sandpaper of count # 100, and then fine burrs are removed. It was removed with a utility knife, and two large and small plates were used as test pieces.
The two test pieces are aged in an oven adjusted to 80 ° C. ± 5 ° C. for 300 hours, cooled at 25 ° C. for 24 hours, and then the large test piece and the small test piece are separated into a stick slip tester SSP-02 manufactured by ZIEGLER. The noise risk value when rubbed three times with an amplitude of 20 mm under four conditions of load 5N, 40N, speed 1mm / sec, and 10mm / sec in an atmosphere of temperature 23 ° C and humidity 50% RH. It was measured. Then, the numerical value of the condition having the largest abnormal noise risk value was extracted and used as the measured value. The larger the abnormal noise risk value, the higher the risk of squeaking noise, and the abnormal noise risk value of 3 or less is good.

12. Each glossy thermoplastic resin composition is injection-molded by Toshiba Machine's IS-170FA injection molding machine at a cylinder temperature of 240 ° C., an injection pressure of 50 MPa, and a mold temperature of 60 ° C. A plate (tray lid) was obtained. Using a digital variable angle gloss meter GlossMeter VG7000 manufactured by Nippon Denshoku Kogyo Co., Ltd., the reflected light was measured at the incident angles of 60 ° at the tray lid positions A and B. The positions A and B of the tray lid were as shown in FIG.

The following can be seen from Tables 1 and 2.
Examples 1 to 3 containing both the tapping sound reducing material and the heat aging inhibitor had better gloss than Comparative Example 1 containing the tapping sound reducing material without the heat aging inhibitor. Comparative Example 2 containing more tapping noise reducing material than Comparative Example 1 without a heat aging inhibitor was inferior in squeaking noise suppressing effect to Comparative Example 1, but the heat aging inhibitor was added to the composition of Comparative Example 2. In Examples 4 and 5, both the gloss and the squeaking sound suppressing effect were improved as compared with Comparative Example 2, and the maximum value of the sound pressure of the tapping sound was lowered, and the frequency giving the maximum value was also lowered. Also improved.
From the comparison between Comparative Examples 3 and 4 and Examples 6 to 10, it can be seen that the same result as described above can be achieved in the case of the thermoplastic resin composition [X] containing the polycarbonate resin.

The thermoplastic resin composition of the present invention can be suitably applied as a molding material for providing a molded product having an excellent appearance such as gloss, suppressing the generation of tapping sound, and preferably suppressing the generation of squeaking noise. It can be suitably used as a molding material for vehicle parts such as automobile interior parts.

Claims (9)

A thermoplastic resin composition composed of at least a rubber-reinforced resin (A) having a rubbery portion (a1) and a resin portion (a2).
The rubbery portion (a1) includes a block (I) having a structural unit derived from an aromatic vinyl compound and a structural unit derived from isoprene or isoprene and butadiene, and has a main dispersion of tan δ at 0 ° C. or higher. It contains a rubbery moiety (a1-1) derived from a block copolymer containing a peaked block (II) or a hydrogenated product thereof.
The resin portion (a2) contains a structural unit derived from an aromatic vinyl compound and contains a structural unit.
The thermoplastic resin composition is a thermoplastic resin composition further containing a heat aging inhibitor (B). The thermoplastic resin composition according to claim 1, wherein the minimum value of the loss factor (η) in the frequency range of 20 to 12,400 Hz is 0.02 or more when measured under the following conditions.
Measurement condition:
Using a test piece prepared by cutting a flat plate with a thickness of 2 mm molded using an injection molding machine into a flat plate with a length of 250 mm, a width of 10 mm, and a thickness of 2 mm, by the central vibration method according to the provisions of JIS K 7244-1. Measured at a temperature of 23 ° C. The thermoplastic resin composition according to claim 1 or 2, wherein the rubbery portion (a1) further contains a rubbery portion (a1-2) derived from an ethylene / α-olefin rubbery polymer. The rubber-reinforced resin (A) comprises a rubbery portion (a1-1) derived from the block copolymer or its hydrogenated additive and a resin portion (a2) containing a structural unit derived from an aromatic vinyl-based compound. A rubber-reinforced resin (A1) having a rubbery portion (a1-2) derived from an ethylene / α-olefin rubbery polymer and a resin portion (a2) containing a structural unit derived from an aromatic vinyl-based compound. The thermoplastic resin composition according to claim 3, which comprises a rubber-reinforced resin (A2) having. The thermoplastic resin composition according to claim 3, wherein the rubbery portion (a1) further contains a rubbery portion (a1-3) derived from a diene-based rubbery polymer. The rubber-reinforced resin (A) comprises a rubbery portion (a1-1) derived from the block copolymer or its hydrogenated additive and a resin portion (a2) containing a structural unit derived from an aromatic vinyl-based compound. A rubber-reinforced resin (A1) having a rubbery portion (a1-2) derived from an ethylene / α-olefin rubbery polymer and a resin portion (a2) containing a structural unit derived from an aromatic vinyl-based compound. A rubber-reinforced resin having a rubber-reinforced resin (A2), a rubbery portion (a1-3) derived from a diene-based rubbery polymer, and a resin portion (a2) containing a structural unit derived from an aromatic vinyl-based compound. The thermoplastic resin composition according to claim 5, which comprises (A3). The thermoplastic resin composition according to any one of claims 1 to 6, wherein the rubber content is 5 to 60% by mass. A molded product comprising the thermoplastic resin composition according to any one of claims 1 to 7. A block (I) having a structural unit derived from an aromatic vinyl-based compound and a block (II) having a structural unit derived from isoprene or isoprene and butadiene and having a peak of the main dispersion of tan δ at 0 ° C. or higher are provided. A rubber-reinforced resin (A1) having a rubbery portion (a1-1) derived from a block copolymer containing or a hydrogenated product thereof and a resin portion (a2) containing a structural unit derived from an aromatic vinyl-based compound. A tapping noise reducing material for a thermoplastic resin composition containing a heat aging inhibitor.

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