Resin composition

Abstract

To provide a resin composition having high vibration-damping properties over a wide temperature range (for example, a temperature range of ≥ 15 °C).SOLUTION: A resin composition (X) comprising 5 to 49 parts by mass of a 4-methyl-1-pentene / α - olefin copolymer (A), and 95 to 51 parts by mass of a styrene-based elastomer (B) satisfying at least one selected from the group consisting of a requirement (B-a) and a requirement (B-b). Requirement (B-a); a hydrogenated product of a block copolymer comprising a polymer block comprising a structural unit derived from styrenes and a random copolymer block of dienes and the styrenes, wherein the content of the structural unit derived from styrenes is 26% by mass or more. A peak temperature of tan δ obtained by performing dynamic viscoelasticity measurement at a 1Hz frequency in a temperature range of -70 °C. to 100 °C. is - 20 °C. or higher.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition. [Background technology]

[0002] In recent years, it has become important to prevent vibrations and the resulting noise in automobiles, home appliances, precision instruments, etc., and to create a comfortable living environment, and high vibration-damping properties have become necessary for the components that make up these machines and instruments. Also, in the field of audiovisual equipment such as audio equipment, video equipment, and speakers, greater vibration-damping performance than ever before has been required to achieve high-quality sound and image quality.

[0003] Butyl rubber and halogenated butyl rubber have been mainly used as vibration-damping materials (for example, Patent Documents 1 and 2). However, the need for a vulcanization process limits the shape of the molded product, and vulcanized rubber products are prone to burrs, requiring post-processing, which reduces productivity and leads to high costs. Furthermore, there is a risk of toxic gases being generated when waste materials containing halogenated butyl rubber are incinerated.

[0004] Meanwhile, in recent years, thermoplastic elastomers, which are rubber-like soft materials that do not require a vulcanization process and have moldability similar to that of thermoplastic resins, have been attracting attention in the fields of automobile parts, home appliance parts, miscellaneous goods, footwear, wire coatings, and even packings such as O-rings. Currently, various polymers of such thermoplastic elastomers, such as polyolefin-based, polyurethane-based, polyester-based, polystyrene-based, and polyvinyl chloride-based polymers, have been developed and are commercially available.

[0005] Furthermore, Patent Document 3 proposes a resin composition containing 95 to 51 parts by mass of a hydrogenated styrene block copolymer (A) having a polymer block content of 25% by mass or less consisting of structural units derived from styrenes, and 5 to 49 parts by mass of a specified 4-methyl-1-pentene / α-olefin copolymer (B), in which two or more loss tangent (tanδ) peaks are observed in the temperature range of −60 to +80°C and one or more peaks are observed in the temperature range of +10 to +50°C when measured at a measurement frequency of 1.6 Hz. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 9-003278 [Patent Document 2] Japanese Patent Application Publication No. 9-071700 [Patent Document 3] Japanese Patent Application Publication No. 2017-197682 Summary of the Invention [Problem to be solved by the invention]

[0007] The composition described in Patent Document 3 is a resin composition that has a good balance of vibration-damping performance, represented by low rebound resilience, and low permanent set properties. However, since the temperature range in which vibration-damping properties can be obtained is limited, it may be difficult to obtain sufficient vibration-damping properties depending on the application.

[0008] The present invention has been made in view of the above, and an object of the present invention is to provide a resin composition that has high vibration damping properties over a wide temperature range (for example, a temperature range of 15° C. or higher). [Means for solving the problem]

[0009] As a result of further research, the present inventors have found that the above-mentioned problems can be solved by the following configuration example.

[0010] [1] 5 to 49 parts by mass of a 4-methyl-1-pentene-α-olefin copolymer (A), 95 to 51 parts by mass of a styrene-based elastomer (B) that satisfies at least one selected from the group consisting of the following requirements (Ba) and (Bb): A resin composition (X) containing the above (where the total of the 4-methyl-1-pentene·α-olefin copolymer (A) and the styrene-based elastomer (B) is 100 parts by mass). Requirement (Ba): A hydrogenated product of a block copolymer comprising a polymer block consisting of structural units derived from styrenes and a random copolymer block of a diene and the styrenes, wherein the content of structural units derived from styrenes is 26% by mass or more. Requirement (Bb): The peak temperature of tan δ obtained by measuring dynamic viscoelasticity at a frequency of 1 Hz in a temperature range of −70 to 100° C. is −20° C. or higher.

[0011] [2] The resin composition (X) according to [1], which satisfies at least one selected from the group consisting of the following requirements (Xa) to (Xc): Requirement (Xa): The difference between the maximum and minimum values ​​of tan δ obtained by measuring dynamic viscoelasticity at a frequency of 1 Hz in a temperature range of 0 to 40°C is 1.3 or less. Requirement (Xb): The peak of tan δ obtained by measuring dynamic viscoelasticity at a frequency of 1 Hz in the temperature range of −70 to 100° C. has a temperature range of 15° C. or more where the value of tan δ is 0.5 or more. Requirement (Xc): When dynamic viscoelasticity measurement is performed at a frequency of 1 Hz in a temperature range of -70 to 100°C, a tan δ peak is not observed below -20°C.

[0012] [3] The resin composition (X) according to [1] or [2], wherein the 4-methyl-1-pentene-α-olefin copolymer (A) satisfies at least one requirement selected from the group consisting of the following requirements (Aa) and (Ab): Requirement (Aa): The peak temperature of tan δ obtained by measuring dynamic viscoelasticity at a frequency of 1 Hz in a temperature range of −70 to 100° C. is 0° C. or higher and 45° C. or lower. Requirement (Ab): The melting point measured by a differential scanning calorimeter (DSC) is 160°C or less, or no melting point is observed.

[0013] [4] The resin composition (X) according to any one of [1] to [3], wherein the 4-methyl-1-pentene-α-olefin copolymer (A) contains 60 to 97 mol % of structural units (i) derived from 4-methyl-1-pentene and 3 to 40 mol % of structural units (ii) derived from an α-olefin having 2 to 4 carbon atoms (the total of structural units (i) derived from 4-methyl-1-pentene and structural units (ii) derived from an α-olefin having 2 to 4 carbon atoms being 100 mol %).

[0014] [5] Pellets containing the resin composition (X) according to any one of [1] to [4].

[0015] [6] A molded article comprising the resin composition (X) according to any one of [1] to [4].

[0016] [7] A film or sheet comprising the resin composition (X) according to any one of [1] to [4].

[0017] [8] A vibration-damping material or impact-absorbing member comprising the resin composition (X) according to any one of [1] to [4]. [9] A pressure-sensitive adhesive comprising the resin composition (X) according to any one of [1] to [4].

[10] A surface protection film comprising the resin composition (X) according to any one of [1] to [4] or the pressure-sensitive adhesive according to [9]. [Effects of the Invention]

[0018] According to the present invention, a resin composition having high vibration damping properties over a wide temperature range (for example, a temperature range of 15° C. or higher) is provided. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. In this specification, "~" indicating a numerical range is used to mean a range including the numerical values described before and after it as the lower limit value and the upper limit value. In this specification, when "~" indicating a numerical range is used, for example, when expressed as "M~N" (where M and N are numerical values satisfying M < N), it means "M or more and N or less" unless otherwise specified. Also, the unit described after either one of the numerical values before and after "~" is the unit of both the numerical values described before and after "~" unless otherwise specified. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment. In this specification, unless otherwise particularly limited, each component in the composition or each structural unit in the polymer may be included alone or in combination of two or more. In this specification, "sheet" is a concept that includes not only what is generally called "sheet" but also what is generally called "film". In the present invention, room temperature means 23°C.

[0020] ≪Resin Composition (X)≫ The resin composition (X) according to an embodiment of the present invention contains a 4-methyl-1-pentene·α-olefin copolymer (A) having specific physical properties and a styrene-based elastomer (B) having specific physical properties in a specific ratio. In the following description, the 4-methyl-1-pentene·α-olefin copolymer (A) may sometimes be simply referred to as "copolymer (A)".

[0021] The content of copolymer (A) in resin composition (X) is 5 to 49% by mass, relative to 100% by mass of the total of copolymer (A) and styrene-based elastomer (B). The upper limit is preferably 48% by mass, more preferably 45% by mass, and the lower limit is preferably 6% by mass, more preferably 8% by mass, and even more preferably 9% by mass. That is, the content of copolymer (A) is 5 to 49 parts by mass, relative to 100 parts by mass of the total of copolymer (A) and styrene-based elastomer (B). The upper limit is preferably 48 parts by mass, more preferably 45 parts by mass, and the lower limit is preferably 6 parts by mass, more preferably 8 parts by mass, and even more preferably 9 parts by mass. The upper and lower limits of the content of copolymer (A) may be combined in any manner.

[0022] The content of the styrene-based elastomer (B) in the resin composition (X) is 51 to 95% by mass, relative to 100% by mass of the total of the copolymer (A) and the styrene-based elastomer (B). The lower limit is preferably 52% by mass, more preferably 55% by mass, and the upper limit is preferably 94% by mass, more preferably 92% by mass, and even more preferably 91% by mass. That is, the content of the styrene-based elastomer (B) is 51 to 95 parts by mass, relative to 100 parts by mass of the total of the copolymer (A) and the styrene-based elastomer (B). The lower limit is preferably 52 parts by mass, more preferably 55 parts by mass, and the upper limit is preferably 94 parts by mass, more preferably 92 parts by mass, and even more preferably 91 parts by mass. The upper and lower limits for the content of the styrene-based elastomer (B) may be combined in any desired manner.

[0023] When the contents of copolymer (A) and styrene-based elastomer (B) are within the above ranges, the temperature range in which the loss tangent (tan δ) of resin composition (X) obtained by dynamic viscoelasticity measurement at a frequency of 1 Hz is relatively high tends to be broad. That is, when the contents of copolymer (A) and styrene-based elastomer (B) are within the above ranges, the resin composition (X) tends to have a relatively broad peak (e.g., 15°C or higher) when the tan δ values ​​obtained by dynamic viscoelasticity measurement are plotted as a function of temperature. Here, the tan δ value is an index of vibration-damping properties, and generally, the larger the tan δ value, the better the vibration-damping properties. Therefore, a wide temperature range in which the tan δ value is high enough to provide good vibration-damping properties for resin composition (X) means that resin composition (X) tends to exhibit high vibration-damping properties over a wide temperature range. Furthermore, when the tan δ value of resin composition (X) is 0.5 or higher, the resin composition (X) tends to have good vibration-damping properties.

[0024] The resin composition (X) preferably satisfies at least one requirement selected from the group consisting of the following requirements (Xa), (Xb), and (Xc), more preferably satisfies two requirements selected from the group consisting of the following requirements (Xa), (Xb), and (Xc), and even more preferably satisfies the following three requirements (Xa), (Xb), and (Xc).

[0025] [Requirements (Xa)] The difference between the maximum and minimum values ​​of tan δ obtained by dynamic viscoelasticity measurement at a frequency of 1 Hz in a temperature range of 0 to 40°C is preferably 1.3 or less, more preferably 1.29 or less. The smaller the difference between the maximum and minimum values ​​of tan δ, the smaller the temperature dependency of the vibration damping properties, which is preferable. There are no particular restrictions on the lower limit of the difference between the maximum and minimum values ​​of tan δ, but since sufficient vibration damping properties can be obtained, it is usually 0.5. Here, the fact that the difference between the maximum and minimum values ​​of tan δ of resin composition (X) is within the above range indicates that the shape of the tan δ peak of resin composition (X) is broad and that the vibration damping properties are less likely to vary with temperature (i.e., the temperature dependency of the vibration damping properties is low). By using resin composition (X) in which the difference between the maximum and minimum values ​​of tan δ is within the above range, it is possible to easily form a molded article, in particular a vibration-damping member, which has vibration-damping properties that are less likely to fluctuate over a wide temperature range and has excellent vibration-damping properties. The loss factor tanδ can be calculated as the ratio (G" / G') of the storage modulus (G') to the loss modulus (G") using the storage modulus (G') and loss modulus (G") obtained during measurement of dynamic viscoelasticity. Specifically, tanδ is measured by the method described in the examples below.

[0026] [Requirements (Xb)] The peak of loss factor tan δ, obtained by dynamic viscoelasticity measurement at a frequency of 1 Hz in a temperature range of -70 to 100°C, has a temperature range in which the value of tan δ is 0.5 or greater, preferably 15°C or greater, more preferably 16°C or greater, and even more preferably 17°C or greater. Here, the peak of tan δ is the peak observed when the value of tan δ is plotted as a function of the temperature at which the value is obtained. The upper limit of the temperature range in which the value of tan δ is 0.5 or greater at the peak of tan δ is preferably 70°C. When the width of the temperature range in which the value of tan δ at the peak of tan δ is 0.5 or more is within the above range, it can be said that the temperature range in which the loss factor tan δ is 0.5 or more is wide. Here, when the value of tan δ of resin composition (X) is 0.5 or more, the vibration damping properties of resin composition (X) tend to be good, and therefore, by using such resin composition (X), a molded product, particularly a vibration damping member, that has excellent vibration damping properties over a wide temperature range can be easily formed.

[0027] [Requirements (Xc)] When dynamic viscoelasticity measurement is performed at a temperature range of -70 to 100°C and a frequency of 1 Hz, a tan δ peak is preferably not observed below -20°C. That is, the tan δ peak is preferably observed only at temperatures of -20°C or higher. Here, the tan δ peak is a peak observed when the tan δ values ​​obtained in the dynamic viscoelasticity measurement are plotted as a function of the temperature at which the values ​​were obtained. The tan δ peak is more preferably observed only at -10°C to 60°C, even more preferably only at -5°C to 55°C, particularly preferably only at 0°C to 50°C, and even more preferably only at 5 to 45°C.

[0028] The fact that the tan δ peak of resin composition (X) is not observed below -20°C means that the tan δ peak of styrene-based elastomer (B) is not observed below -20°C, indicating that the temperature difference between the tan δ peak of styrene-based elastomer (B) and the tan δ peak of copolymer (A) is relatively small. As a result, the tan δ peak of resin composition (X) tends to fall within the range of -10°C to 60°C. When the tan δ peak of resin composition (X) is within the range of -10°C to 60°C, the shape of the tan δ peak of resin composition (X) tends to be broad, and the vibration damping properties are less likely to vary with temperature (the temperature dependence of the vibration damping properties is reduced). As a result, the resin composition (X) and molded articles obtained from the resin composition (X) exhibit high vibration damping properties over a wide range of environmental temperatures.

[0029] <4-methyl-1-pentene / α-olefin copolymer (A)> The copolymer (A) used in the resin composition (X) may be one type or two or more types. The copolymer (A) preferably satisfies at least one requirement selected from the group consisting of the following requirements (Aa) and (Ab), and more preferably satisfies both the following requirements (Aa) and (Ab).

[0030] [Requirements (Aa)] The peak temperature of tan δ obtained by dynamic viscoelasticity measurement at a frequency of 1 Hz in a temperature range of −70 to 100° C. is preferably 0 to 45° C. Here, the peak of tan δ is a peak observed when the value of tan δ is plotted as a function of the temperature at which the value is obtained. The lower limit of the peak temperature of tan δ is more preferably 20° C., and even more preferably 25° C., and the upper limit is more preferably 40° C. The upper and lower limits of the peak temperature of tan δ may be combined in any desired manner. When the peak temperature of tan δ of copolymer (A) is within the above temperature range, the value of tan δ of resin composition (X) obtained using copolymer (A) at around room temperature can be further increased, and a molded article having better vibration damping properties at around room temperature can be easily formed from the resin composition (X). Specifically, the peak temperature of tan δ is measured by the method described in the examples below.

[0031] [Requirements (Ab)] The melting point (Tm) of the copolymer (A) observed by differential scanning calorimetry (DSC) is 160°C or lower, or the melting point (Tm) of the copolymer (A) is not observed by DSC. When the melting point of the copolymer (A) is observed by DSC, the melting point is preferably 145°C or lower, more preferably 135°C or lower. When the copolymer (A) satisfies the requirement (Ab), the resin composition (X) and the molded article obtained from the resin composition (X) tend to have better vibration absorption and stress relaxation properties. The melting point of the copolymer (A) can be measured by DSC under the conditions described in the examples below.

[0032] Copolymer (A) preferably satisfies at least one requirement selected from the group consisting of the following requirements (Ac), (Ad), (Ae), (Af), (Ag) and (Ai), more preferably satisfies two or more requirements, even more preferably satisfies three or more requirements, still more preferably satisfies four or more requirements, and particularly preferably satisfies all of the requirements.

[0033] [Requirements (Ac)] Copolymer (A) preferably contains 60 to 97 mol % of structural units (i) derived from 4-methyl-1-pentene, and preferably contains 3 to 40 mol % of structural units (ii) derived from an α-olefin having 2 to 4 carbon atoms (provided that the total of structural units (i) and structural units (ii) is 100 mol %).

[0034] As used herein, a "structural unit derived from an α-olefin" (i.e., structural unit (ii)) refers to a structural unit represented by -CH-CHR- (R is a hydrogen atom or an alkyl group). Similarly, a "structural unit derived from 4-methyl-1-pentene" (i.e., structural unit (i)) refers to a structural unit represented by -CH-CH(-CHCH(CH))-.

[0035] The lower limit of the content of the structural unit (i) is preferably 60 mol%, more preferably 64 mol%, and even more preferably 68 mol%. Meanwhile, the upper limit of the content of the structural unit (i) is preferably 97 mol%, more preferably 94 mol%, even more preferably 90 mol%, and particularly preferably 88 mol%. The upper and lower limits of the content of the structural unit (i) can be combined in any way. When the content of structural unit (i) is within the above range, the peak temperature of tan δ of copolymer (A) tends to be around room temperature, and therefore the peak temperature of tan δ of resin composition (X) obtained using copolymer (A) can also be easily adjusted to fall within the above range.

[0036] The upper limit of the content of the structural unit (ii) is preferably 40 mol%, more preferably 36 mol%, and even more preferably 32 mol%. Meanwhile, the lower limit of the content of the structural unit (ii) is preferably 3 mol%, more preferably 6 mol%, even more preferably 10 mol%, and particularly preferably 12 mol%. The upper and lower limits of the content of the structural unit (ii) can be combined in any way. The contents of the structural units (i) and (ii) are determined under the conditions described in the examples below. 13It can be calculated by measuring C-NMR.

[0037] Examples of the α-olefin having 2 to 4 carbon atoms in the structural unit (ii) include ethylene, propylene, and 1-butene. Among these, ethylene and propylene are preferred, with propylene being particularly preferred, because they provide high stress absorption and polyolefin modification properties. The α-olefins having 2 to 4 carbon atoms may be used alone or in combination of two or more.

[0038] The copolymer (A) may contain a structural unit (iii) other than the structural units (i) and (ii) described above, as long as the object of the present invention is not impaired. Examples of the structural unit (iii) include structural units derived from monomers other than 4-methyl-1-pentene and α-olefins having 2 to 4 carbon atoms. Examples of the other monomers include 5-vinyl-2-norbornene and 5-ethylidene-2-norbornene. The content of the structural unit (iii) is preferably 10 parts by mol or less, and more preferably 5 parts by mol or less, per 100 parts by mol of the total of the structural units (i) and (ii). The other monomers may be used alone or in combination of two or more.

[0039] The 4-methyl-1-pentene and α-olefin monomers from which the structural units contained in copolymer (A) are derived, as well as the monomer from which the structural unit (iii) is derived, may be fossil fuel-derived monomers, biomass-derived monomers, or a combination of fossil fuel-derived and biomass-derived monomers. Furthermore, any of the 4-methyl-1-pentene and α-olefin monomers from which the structural unit (iii) is derived may be chemically recycled monomers or fossil fuel-derived monomers.

[0040] [Requirements (Ad)] The peak value of tan δ obtained by dynamic viscoelasticity measurement in a temperature range of −70 to 100° C. at a frequency of 1 Hz is preferably 0.6 to 5.0. The peak value of tan δ is more preferably 1.0 to 5.0, even more preferably 1.5 to 5.0, and particularly preferably 2.0 to 4.0. When the peak value of tan δ of the copolymer (A) is within the above range, the molded article formed from the resin composition (X) obtained using the copolymer (A) can change the vibration absorption property, material hardness, and followability depending on the tensile and deformation speeds, and therefore has better vibration damping properties. The peak value of tan δ is specifically measured by the method described in the examples below.

[0041] [Requirements (Ae)] The copolymer (A) preferably has an intrinsic viscosity [η] of 0.1 to 5.0 dl / g, more preferably 0.5 to 4.0 dl / g, and even more preferably 0.5 to 3.5 dl / g, measured in decalin at 135°C. When the intrinsic viscosity [η] is within the above range, the resin composition (X) can be easily molded into a sheet-like molded product and a film-like molded product. The intrinsic viscosity [η] of copolymer (A) can be adjusted to the above range by adding hydrogen during the production of copolymer (A) to control the molecular weight and polymerization activity. The greater the amount of hydrogen added, the lower the intrinsic viscosity [η] of copolymer (A). Furthermore, the higher the polymerization activity, the higher the polar viscosity.

[0042] Requirements The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (molecular weight distribution: Mw / Mn) of the copolymer (A) measured by gel permeation chromatography (GPC) is preferably in the range of 1.0 to 3.5. The Mw / Mn is more preferably 1.2 to 3.0, and even more preferably 1.5 to 2.8. When Mw / Mn is within the above range, the copolymer (A) is less likely to suffer from a decrease in molecular weight and a decrease in moldability due to a low stereoregularity polymer, and the resin composition (X) can be easily molded into sheet-like and film-like molded articles.

[0043] [Requirements (Ag)] The weight average molecular weight (Mw) of the copolymer (A) measured by GPC is preferably 500 to 10,000,000 in terms of polystyrene. The Mw is more preferably 1,000 to 5,000,000, and even more preferably 1,000 to 2,500,000. When Mw is within the above range, a molded article having a good balance between moldability and vibration damping properties can be easily formed from the resin composition (X).

[0044] The copolymer (A) having Mw / Mn and Mw within the above ranges can be produced, for example, by using a metallocene catalyst when producing the copolymer (A). The Mw / Mn and Mw can be determined, for example, by measuring by the method described in the Examples below and analyzing using a calibration curve prepared using a standard polystyrene sample.

[0045] [Requirements (Ah)] The density of the copolymer (A) measured in accordance with JIS K 7112:1999 (density gradient tube method) is preferably 830 to 870 kg / m 3 is. The density is more preferably 830 to 865 kg / m 3 , more preferably 830 to 855 kg / m 3 is. By using the copolymer (A) having a density within the above range, it tends to be possible to easily form a lighter molded article from the resin composition (X). The density can be appropriately changed by adjusting the composition ratio of the comonomers in the copolymer (A).

[0046] [Requirements (Ai)] The melt flow rate (MFR) of the copolymer (A) measured in accordance with ASTM D1238 at 230° C. under a load of 2.16 kg is preferably 4.0 to 30 g / 10 min. The MFR is more preferably 7.0 to 15 g / 10 min, and even more preferably 7.0 to 13 g / 10 min. By using the copolymer (A) having an MFR within the above range, the resulting resin composition (X) can be easily formed into good pellets, sheets, films, etc., which is advantageous in producing molded articles of the resin composition (X).

[0047] [Method for producing copolymer (A)] The method for producing the copolymer (A) is not particularly limited, and the copolymer (A) can be produced by a conventionally known method. Suitable examples of the catalyst used for producing the copolymer (A) include conventionally known catalysts, such as magnesium-supported titanium catalysts and metallocene catalysts described in WO 01 / 053369, WO 01 / 027124, JP-A 3-193796, JP-A 02-41303, and WO 2011 / 055803.

[0048] <Styrene-based elastomer (B)> The styrene-based elastomer (B) used in the resin composition (X) may be one type or two or more types. The styrene-based elastomer (B) satisfies at least one of the following requirements (Ba) and (Bb), and more preferably satisfies both of the following requirements (Ba) and (Bb). That is, the styrene-based elastomer (B) satisfies at least one selected from the group consisting of the following requirements (Ba) and (Bb).

[0049] [Requirements (Ba)] The styrene elastomer (B) is a hydrogenated product of a block copolymer consisting of a polymer block of structural units derived from styrenes and a random copolymer block of a diene and the styrenes, and the content of structural units derived from styrenes is 26% by mass or more (where the mass of the styrene elastomer (B) is taken as 100% by mass). In the following description, the random copolymer block of a diene and the styrenes may be simply referred to as a "random copolymer block."

[0050] In the styrene-based elastomer (B), examples of the styrenes from which the polymer block composed of structural units derived from styrenes are derived include styrene, α-methylstyrene, vinyltoluene, p-methylstyrene, pt-butylstyrene, o-ethylstyrene, and o,p-dichlorostyrene, with styrene being preferred. The structural units contained in the polymer block may be derived from one or more of these.

[0051] The random copolymer that forms the random copolymer block in the styrene-based elastomer (B) is a random copolymer of the above-mentioned styrenes and conjugated dienes. Examples of the conjugated dienes include butadiene, isoprene, isobutylene, butadiene / isoprene copolymer, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, and chloroprene. Among these, butadiene, and one or more dienes consisting of isoprene and isobutylene are preferably used.

[0052] The content of structural units derived from styrenes in the styrene-based elastomer (B) is 26% by mass or more, preferably 28% by mass or more, and more preferably 30% by mass or more (where the mass of the styrene-based elastomer (B) is 100% by mass). The content of structural units derived from styrenes in the styrene-based elastomer (B) is preferably 90% by mass or less, more preferably 88% by mass or less (where the mass of the styrene-based elastomer (B) is 100% by mass). The upper and lower limits of the content of structural units derived from styrenes may be arbitrarily combined. When the content of structural units derived from styrenes satisfies the above range, the resin composition (X) containing the styrene-based elastomer (B) tends to exhibit a relatively broad peak (e.g., 15°C or more) when the tan δ value obtained by dynamic viscoelasticity measurement is plotted as a function of temperature. In other words, a resin composition (X) containing a styrene-based elastomer (B) in which the content of structural units derived from styrenes satisfies the above range tends to exhibit high vibration damping properties over a wide temperature range. The content of structural units derived from styrenes in the styrene-based elastomer (B) is the total of all structural units contained in the polymer block consisting of structural units derived from styrenes and the structural units derived from styrenes among the structural units in the random copolymer block.

[0053] Furthermore, in the present invention, there is no prohibition whatsoever on using two or more types of styrene-based elastomers (B) having different compositions.

[0054] [Requirements (Bb)] The peak temperature of tan δ obtained by measuring dynamic viscoelasticity at a frequency of 1 Hz in a temperature range of -70 to 100°C is -20°C or higher. The lower limit of the peak temperature of tan δ is preferably −15° C., more preferably 0° C., and the upper limit is preferably 60° C. The upper and lower limits of the peak temperature of tan δ may be combined in any desired manner. When the tan δ peak temperature of the styrene elastomer (B) is within this temperature range, the tan δ value of the resin composition (X) obtained using the styrene elastomer (B) at around room temperature can be further increased. Furthermore, when the tan δ peak temperature of the styrene elastomer (B) is within this temperature range, the temperature difference between the tan δ peak of the styrene elastomer (B) and the tan δ peak of the copolymer (A) is relatively small, which makes it easier to broaden the temperature range over which the tan δ peak is high when the styrene elastomer (B) and the copolymer (A) are kneaded. In other words, it makes it easier to broaden the temperature range over which the tan δ peak is high in the resulting resin composition (X). The peak temperature of tan δ is specifically measured by the method described in the examples below.

[0055] Commercially available styrene elastomers (B) include trade names SOE S1605 (manufactured by Asahi Kasei Corporation: styrene content = 67 mass%, tanδ peak = 17°C, "SOE" is a registered trademark) and Kraton MD6951 (manufactured by Kraton Corporation: styrene content = 34 mass%, tanδ peak = -3°C).

[0056] <Other components contained in the method for producing resin composition (X)> The resin composition (X) may be a composition consisting only of the copolymer (A) and the styrene-based elastomer (B), but may also contain other conventionally known components in addition to the copolymer (A) and the styrene-based elastomer (B), as necessary. The other components may each be used alone or in combination of two or more.

[0057] Examples of the other components include tackifiers, weather resistance stabilizers, heat resistance stabilizers, antistatic agents, antislip agents, antiblocking agents, antifogging agents, lubricants, pigments, dyes, plasticizers, antioxidants, hydrochloric acid absorbers, antioxidants, crystal nucleating agents, antifungal agents, antibacterial agents, flame retardants, fillers (inorganic fillers, organic fillers), and softeners.

[0058] The amount of the other components added is not particularly limited as long as it does not impair the object of the present invention, but is 0.01 to 10 parts by mass, preferably 0.01 to 5 parts by mass, and more preferably 0.01 to 3 parts by mass, per 100 parts by mass of the resin composition (X).

[0059] <Method for producing resin composition (X)> The method for producing the resin composition (X) is not particularly limited, and includes conventionally known production methods. As the method for producing the resin composition (X), a melt-kneading method is preferred in which the resin composition (X) is produced by melt-kneading the copolymer (A), the styrene-based elastomer (B), and optionally the other components. The melt-kneading method is not particularly limited, and examples thereof include a method of melt-kneading at 150 to 250°C using a commonly used known mixer such as a kneader, roll mill, Banbury mixer, single-screw or twin-screw extruder. Among these, the use of a twin-screw extruder is preferred from the viewpoints of mixability and productivity. This method can produce a high-quality resin composition (X) in which the components are uniformly dispersed and mixed.

[0060] <Molded body> The resin composition (X) according to one embodiment of the present invention is usually molded into a shape according to a desired application and used as a molded article, such as pellets, films, sheets, toys, daily commodities, and housings for electronic devices. The molded article may contain a resin composition (X).

[0061] The method for producing the molded article (molding method) is not particularly limited, and the molded article can be produced by any conventionally known molding method except for using the resin composition (X).

[0062] Suitable examples of the method for producing the molded article include extrusion sheet molding, compression molding, and injection molding, of which extrusion sheet molding and injection molding are preferred. When the resin composition (X) is processed by injection molding, a molded article containing the resin composition (X) can be suitably obtained.

[0063] The extrusion sheet molding method can be exemplified by a method using a general T-die extruder. Specific examples of the extrusion sheet molding method include a method in which molding is performed using a single-screw extruder at a cylinder temperature of 150 to 250°C and a cast roll temperature of 0 to 70°C to form a sheet or film. When the molded product is a film, the film can be appropriately stretched during or after molding. The film can be stretched uniaxially or biaxially.

[0064] When the molded article is a sheet or film, the thickness of the sheet or film is usually 5 to 1000 μm, preferably 30 to 200 μm, although it depends on the intended use. When the thickness of the sheet or film is within the above range, productivity is excellent, pinholes and the like do not occur during molding of the sheet or film, and sufficient strength is obtained, which is preferable.

[0065] When forming a sheet-like or film-like molded article, the surface of the obtained sheet or film may be embossed, and the sheet may be stretched during or after molding. The sheet may be stretched uniaxially or biaxially.

[0066] <Adhesives and surface protection films> The adhesive according to one embodiment of the present invention (hereinafter also referred to as "the adhesive") is not particularly limited as long as it contains the resin composition (X), but typically consists of (only) the resin composition (X). This pressure-sensitive adhesive can be used as a material for forming the pressure-sensitive adhesive layer (L1) of the surface protection film described below. The surface protection film has an adhesive layer (L1) formed from the resin composition (X) or the present adhesive, and a substrate layer (L2). The adhesive layer (L1) is not particularly limited as long as it contains the resin composition (X), but is usually formed from the resin composition (X) or the present adhesive (only). The substrate layer (L2) is not particularly limited, and a conventionally known substrate layer can be used.

[0067] <Application> The resin composition (X) is suitable for use as, for example, a vibration-damping material, a pressure-sensitive adhesive, or an adhesive layer (L1) of a surface protection film. Examples of vibration-damping materials include vibration-damping members, shock-absorbing members, vibration-absorbing members, and resonance-absorbing members. In particular, the resin composition (X) has high stress absorption at room temperature, making it suitable for use as a vibration-damping material used at room temperature, specifically, for vehicle parts for automobiles and railways, civil engineering and building materials, electrical appliances, and the like.

[0068] Examples of the vehicle parts include ceiling materials, interior seats, bumper moldings, side moldings, air spoilers, air duct hoses, cup holders, side brake grips, shift knob covers, seat adjustment knobs, flapper door seals, wire harness grommets, rack and pinion boots, suspension cover boots, glass guides, inner belt line seals, roof guides, trunk lid seals, molded quarter window gaskets, corner moldings, glass encapsulations, hood seals, glass run channels, secondary seals, various types of packing, bumper parts, body panels, side shields, instrument panel skins, door skins, ceiling skins, weatherstrip materials, hoses, steering wheels, boots, wire harness covers, and seat adjuster covers.

[0069] Examples of the civil engineering and building materials include civil engineering and building materials such as ground improvement sheets, water supply boards, and noise and vibration prevention walls, various gaskets and sheets for civil engineering and construction, water stop materials, joint materials, architectural window frames, and vibration suppression grip materials used in rotating equipment such as electric drills.

[0070] Examples of the electrical products include vibration damping members for devices such as optical magnetic disks; insulators; vibration damping members for copy machines; vibration damping members for motors; vibration damping members for car navigation systems; vibration damping members for machine tools, industrial machinery and equipment, etc.; vibration damping members for electrical products such as office automation equipment and home appliances; and vibration damping members for acoustic equipment such as audio products.

[0071] When used as a surface protection film, the molded article can be suitably used as a surface protection film for protecting metal plates such as aluminum plates, steel plates, and stainless steel plates, coated plates thereof, or processing materials such as glass plates and synthetic resin plates, as well as home appliances, automobile parts, and electronic components using these materials. Therefore, the molded article can be suitably used, for example, in adhesive films, protective film adhesive layers, and other adhesives; films or tapes in the electronics field such as semiconductor process protection films, lens protection films, backgrinding tapes for semiconductor wafers, dicing tapes, and protective tapes for printed circuit boards; window glass protection films; and baked coating films. It is particularly suitable for prism sheets and reflective sheets with many uneven surfaces, and sheets for protecting textured surfaces. An example of the application of the molded article to protective tapes for printed circuit boards is a protective film for plating masks used during the plating process of flexible printed circuit boards. [Example]

[0072] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0073] [Synthesis Example 1] Synthesis of 4-methyl-1-pentene-α-olefin copolymer (A-1) A 1.5 L stainless steel autoclave equipped with a stirring blade and thoroughly purged with nitrogen was charged with 300 mL of n-hexane (dried over activated alumina under a dry nitrogen atmosphere) and 450 mL of 4-methyl-1-pentene at 23° C. 0.75 mL of a 1.0 mmol / mL toluene solution of triisobutylaluminum (TIBAL) was charged into the autoclave, and the stirrer was turned on.

[0074] Next, the autoclave was heated until the internal temperature reached 60°C, and pressurized with propylene to a total pressure (gauge pressure) of 0.40 MPa. Next, 0.34 mL of a toluene solution containing 1 mmol of methylaluminoxane (calculated as Al) and 0.01 mmol of diphenylmethylene(1-ethyl-3-t-butyl-cyclopentadienyl)(2,7-di-t-butyl-fluorenyl)zirconium dichloride, which had been prepared in advance, was introduced into the autoclave under pressure with nitrogen to initiate the polymerization reaction. During the polymerization reaction, the internal temperature of the autoclave was adjusted to 60°C.

[0075] Sixty minutes after the start of polymerization, 5 mL of methanol was injected into the autoclave with nitrogen to terminate the polymerization reaction, and the autoclave was then depressurized to atmospheric pressure. After depressurization, acetone was added to the resulting reaction solution while stirring, yielding a polymerization reaction product containing the solvent.

[0076] The resulting solvent-containing polymerization reaction product was then dried under reduced pressure at 100°C for 12 hours to obtain 36.9 g of powdery 4-methyl-1-pentene·α-olefin copolymer (A-1) (hereinafter also referred to as "copolymer (A-1)"). The resulting copolymer (A-1) was measured for various physical properties as follows, and the results are shown in Table 1.

[0077] 〔composition〕 The content (mol %) of each structural unit (4-methyl-1-pentene and α-olefin) in copolymer (A-1) was measured under the following conditions: 13 Measurement was performed by C-NMR.

[0078] · 13 C-NMR measurement conditions Measurement equipment: Nuclear magnetic resonance equipment (ECP500 model, manufactured by JEOL Ltd.) Observation core: 13 C(125MHz) Sequence: Single pulse proton decoupling Pulse width: 4.7 μsec (45° pulse) Repeat time: 5.5 seconds Accumulation count: 10,000 times or more Solvent: orthodichlorobenzene / deuterated benzene (volume ratio: 80 / 20) mixed solvent Sample concentration: 55mg / 0.6mL ·Measurement temperature: 120℃ Chemical shift reference value: 27.50 ppm

[0079] The content of the structural unit (i) derived from 4-methyl-1-pentene in the copolymer (A-1) was 72.5 mol %, and the content of the structural unit (ii) derived from propylene was 27.5 mol %.

[0080] [Intrinsic viscosity [η]] The intrinsic viscosity [η] of the copolymer (A-1) was measured at 135° C. in a decalin solvent using an Ubbelohde viscometer as a measuring device. Specifically, approximately 20 mg of copolymer (A-1) was dissolved in 25 mL of decalin, and the specific viscosity η SP After diluting this decalin solution by adding 5 mL of decalin, the specific viscosity η SP This dilution procedure was repeated two more times, and the η when the concentration (C) was extrapolated to 0 was measured. SP The value of / C was calculated as the intrinsic viscosity [η] (unit: dl / g) (see the following formula 1). The intrinsic viscosity [η] of the copolymer (A-1) was 1.5 dl / g. [η]=lim(η SP / C) (C→0)...(Formula 1)

[0081] [Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)] The weight-average molecular weight (Mw) of copolymer (A-1) and the molecular weight distribution (Mw / Mn), which is the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), were calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC) under the following measurement conditions: The weight-average molecular weight (Mw) of copolymer (A-1) was 337,000, and the molecular weight distribution (Mw / Mn) of copolymer (A-1) was 2.1.

[0082] GPC measurement conditions Measurement equipment: GPC (ALC / GPC 150-C plus type, differential refractometer detector integrated, manufactured by Waters) Column: Two GMH6-HT (Tosoh Corporation) and two GMH6-HTL (Tosoh Corporation) columns connected in series Eluent: o-dichlorobenzene Column temperature: 140℃ ·Flow rate: 1.0mL / min

[0083] 〔density〕 The density of the copolymer (A-1) was measured in accordance with JIS K 7112:1999 (density gradient tube method). The density of the copolymer (A-1) was 839 kg / m 3 It was.

[0084] [Melt flow rate (MFR)] The melt flow rate (MFR) of the copolymer (A-1) was measured in accordance with ASTM D1238 at 230°C under a load of 2.16 kg. The unit is g / 10 min. The MFR of the copolymer (A-1) was 11 g / 10 min.

[0085] [Melting point (Tm)] The melting point (Tm) of copolymer (A-1) was measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.). Approximately 5 mg of copolymer (A-1) was sealed in a measurement aluminum pan and heated from room temperature to 200°C at 10°C / min. To completely melt the copolymer, it was held at 200°C for 5 minutes and then cooled to -50°C at 10°C / min. After leaving it at -50°C for 5 minutes, it was heated a second time to 200°C at 10°C / min, and the peak temperature (°C) during this second heating was taken as the melting point (Tm) of the copolymer. When multiple peaks were detected, the peak detected at the highest temperature was used as the melting point (Tm). The melting point (Tm) of copolymer (A-1) was not observed.

[0086] [Dynamic viscoelasticity] Copolymer (A-1) was pressed at a gauge pressure of 10 MPa for 5 minutes using a hydraulic heat press (NS-50) manufactured by Shinto Metal Industries Co., Ltd. set at 180°C, and then compressed at a gauge pressure of 10 MPa using another hydraulic heat press manufactured by Shinto Metal Industries Co., Ltd. set at 20°C, and cooled for about 5 minutes to obtain a pressed sheet having a thickness of 2 mm, a width of 200 mm, and a length of 200 mm. A 35 mm × 10 mm × 2 mm thick strip was cut out from the pressed sheet. Using the resulting strip and an MCR301 manufactured by ANTON PAAR, the temperature dependence of dynamic viscoelasticity was measured at a frequency of 1.6 Hz in the temperature range of -40 to 150°C, and the temperature (peak temperature) at which the loss factor tanδ due to the glass transition temperature reached its peak value (maximum value) and the value of the loss factor tanδ at that time (peak value) were measured.

[0087] [Table 1]

[0088] <Raw materials> The following raw materials were used in the following examples and comparative examples. [4-methyl-1-pentene-α-olefin copolymer (A)] The copolymer (A-1) synthesized in Synthesis Example 1 was used as the 4-methyl-1-pentene-α-olefin copolymer (A).

[0089] [Styrene-based elastomer (B)] "Styrene-based elastomer (B-1)": SOE S1605, manufactured by Asahi Kasei (content of structural units derived from styrene = 87% by mass, tanδ peak temperature = 16°C)

[0090] [Styrene-based elastomers not included in (B)] "Styrene-based elastomer (cB-1)": Tuftec H1052, manufactured by Asahi Kasei (styrene-derived structural unit content = 20% by mass, tanδ peak temperature = -44°C)

[0091] [Example 1] 10 parts by mass of copolymer (A-1) and 90 parts by mass of styrene-based elastomer (B-1) were kneaded at 150°C using a batch kneader (product name: Labo Plastomill, manufactured by Toyo Seiki Seisakusho, Ltd.) to obtain resin composition (X-1). Resin composition (X-1) was heated at 180°C for 5 minutes using a heating press, and then cooled and pressed to obtain a pressed sheet with a thickness of 2 mm. Dynamic viscoelasticity was measured for a vibration damping material made from this pressed sheet. The results are shown in Table 2.

[0092] [Dynamic viscoelasticity] A rectangular piece measuring 35 mm x 10 mm x 2 mm thick was cut out from the prepared pressed sheet. Using the obtained rectangular piece and an MCR301 manufactured by ANTON Paar, the temperature dependence of dynamic viscoelasticity was measured at a frequency of 1 Hz in the temperature range of -70 to 100°C. The obtained tan δ was plotted as a function of temperature, and the width of the temperature range in which the loss factor tan δ was 0.5 or more was determined at the peak of tan δ. Furthermore, regarding the temperature dependence of the dynamic viscoelasticity, the difference between the maximum and minimum values ​​of the loss factor tan δ in the temperature range of 0 to 40°C (tan δ) was calculated. diff) was calculated. Furthermore, with regard to the temperature dependency of the dynamic viscoelasticity, the temperature (peak temperature) at which the loss factor tan δ reached its peak value (maximum value) and the value of the loss factor tan δ at that time (peak value) were measured. The results are shown in Table 2. In Example 1, multiple tan δ peaks were not observed, but when multiple tan δ peaks were observed, the peak numbers were assigned in order from the lowest temperature peak. That is, the peak at the lowest temperature was designated the first peak, and the peak second from the lowest temperature was designated the second peak. When only one tan δ peak was observed, the observed tan δ peak was designated the first peak.

[0093] [Example 2] A press sheet was prepared in the same manner as in Example 1, except that the amount of copolymer (A-1) used was changed to 20 parts by mass and the amount of styrene-based elastomer (B-1) used was changed to 80 parts by mass, and dynamic viscoelasticity was measured. The results are shown in Table 2.

[0094] [Example 3] A press sheet was prepared in the same manner as in Example 1, except that the amount of copolymer (A-1) used was changed to 40 parts by mass and the amount of styrene-based elastomer (B-1) used was changed to 60 parts by mass, and dynamic viscoelasticity was measured. The results are shown in Table 2.

[0095] [Comparative Example 1] A press sheet was prepared in the same manner as in Example 3, except that the styrene-based elastomer (cB-1) was used instead of the styrene-based elastomer (B-1), and dynamic viscoelasticity measurements were performed. The results are shown in Table 2. In Comparative Example 1, two peaks of tan δ were observed, so the peak on the low temperature side was designated as the first peak and the peak on the high temperature side was designated as the second peak.

[0096] Comparative Example 2 A pressed sheet was prepared in the same manner as in Example 1, except that only the styrene-based elastomer (B-1) was used, and the dynamic viscoelasticity was measured. The results are shown in Table 2.

[0097] Comparative Example 3 A pressed sheet was prepared in the same manner as in Example 1, except that only the styrene-based elastomer (cB-1) was used, and dynamic viscoelasticity measurement was carried out. The results are shown in Table 2.

[0098] [Table 2]

Claims

1. 5 to 49 parts by mass of a 4-methyl-1-pentene / α-olefin copolymer (A); 95 to 51 parts by mass of a styrene-based elastomer (B) that satisfies at least one of the following requirements (Ba) and (Bb): (where the total of the 4-methyl-1-pentene·α-olefin copolymer (A) and the styrene-based elastomer (B) is 100 parts by mass) Requirement (Ba-a): The polymer block is composed of structural units derived from styrenes, and the block copolymer is a hydrogenated product composed of a random copolymer block of a diene and the styrenes, and the content of structural units derived from styrenes is 26% by mass or more. Requirement (Bb): The peak temperature of tan δ obtained by dynamic viscoelasticity measurement at a frequency of 1 Hz in a temperature range of −70 to 100° C. is −20° C. or higher.

2. The resin composition (X) according to claim 1, which satisfies at least one selected from the group consisting of the following requirements (X-a) to (X-c): Requirement (Xa): The difference between the maximum and minimum values ​​of tan δ obtained by measuring dynamic viscoelasticity at a frequency of 1 Hz in a temperature range of 0 to 40° C. is 1.3 or less. Requirement (X-b): When dynamic viscoelasticity is measured at a frequency of 1 Hz in a temperature range of −70 to 100° C., the temperature range in which the tan δ peak is 0.5 or more is 15° C. or more. Requirement (Xc): When dynamic viscoelasticity is measured at a frequency of 1 Hz in a temperature range of -70 to 100°C, no tan δ peak is observed below -20°C.

3. The resin composition (X) according to claim 1, wherein the 4-methyl-1-pentene / α-olefin copolymer (A) satisfies at least one requirement selected from the group consisting of the following requirements (A-a) and (A-b): Requirement (Aa): The peak temperature of tan δ obtained by measuring dynamic viscoelasticity at a frequency of 1 Hz in a temperature range of −70 to 100° C. is 0° C. or higher and 45° C. or lower. Requirement (Ab): The melting point measured by a differential scanning calorimeter (DSC) is 160° C. or less, or no melting point is observed.

4. The 4-methyl-1-pentene / α-olefin copolymer (A) contains 60 to 97 mol% of structural units (i) derived from 4-methyl-1-pentene and 3 to 40 mol% of structural units (ii) derived from an α-olefin having 2 to 4 carbon atoms (the total of structural units (i) derived from 4-methyl-1-pentene and structural units (ii) derived from an α-olefin having 2 to 4 carbon atoms being 100 mol%). Resin composition (X) according to claim 1.

5. A pellet comprising the resin composition (X) according to any one of claims 1 to 4.

6. A molded article comprising the resin composition (X) according to any one of claims 1 to 4.

7. A film or sheet comprising the resin composition (X) according to any one of claims 1 to 4.

8. A vibration-damping material or impact-absorbing member comprising the resin composition (X) according to any one of claims 1 to 4.

9. A pressure-sensitive adhesive comprising the resin composition (X) according to claim 1.

10. A surface protection film comprising the resin composition (X) according to any one of claims 1 to 4 or the pressure-sensitive adhesive according to claim 9.

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