Resin composition, molded body, and method for producing resin composition

Abstract

Provided is a resin composition that contains a polymer including a structural unit derived from a norbornene-based monomer, and a filler composition. The filler composition contains a plate-form filler and a binder, and has a weight reduction ratio of 1.4% or less in a 280°C nitrogen atmosphere.

Description

Resin composition, molded article, and method for producing resin composition

[0001] The present invention relates to a resin composition, a molded article, and a method for producing a resin composition.

[0002] BACKGROUND ART Fillers have conventionally been blended into resin compositions that are the materials for molded articles in order to reinforce the molded articles or to impart various functions to the molded articles.

[0003] For example, Patent Document 1 discloses a polypropylene-based resin composition having high rigidity and excellent heat resistance, which contains a polypropylene-based resin, a predetermined proportion of filler, and a filler dispersant and / or filler binder. Patent Document 2 discloses a thermoplastic polymer granule having excellent handleability and safety, which contains a predetermined proportion of a powdered thermoplastic polymer, a filler, and a binder. Patent Document 3 discloses an electrically insulating thermally conductive resin composition containing a thermoplastic resin, granules obtained by granulating fibers mainly composed of alumina, and an aromatic compound having predetermined physical properties. According to Patent Document 3, the resin composition can be used to produce molded articles having electrical insulation and high thermal conductivity suitable for electrical and electronic components, as well as excellent mechanical strength. Patent Document 4 discloses a thermoplastic resin composition having an excellent balance of physical properties, which contains a thermoplastic resin, a predetermined proportion of granular inorganic filler composed of an inorganic filler and a water-soluble polyester resin binder.

[0004] JP 2023-54403 A JP 2023-15826 A JP 2009-57409 A JP 2007-284502 A

[0005] An object of the present invention is to provide a resin composition which produces pellets with excellent appearance, a molded article using the same, and a method for producing the resin composition.

[0006] The present inventors have conducted extensive research to solve the above-mentioned problems, and have newly discovered that a resin composition containing a polymer containing structural units derived from a norbornene-based monomer (hereinafter, sometimes referred to as a "norbornene-based polymer") and a filler composition, in which the filler composition contains a plate-like filler and a binder and has a weight loss rate of 1.4% or less in a nitrogen atmosphere at 280°C, can reduce gas generation during heat kneading and form pellets with excellent appearance, thereby completing the present invention.

[0007] That is, the present invention aims to advantageously solve the above-mentioned problems, and provides the following resin compositions [1] to [7], molded articles [8] to

[13] , and manufacturing methods

[14] to

[20] .

[0008] [1] A resin composition comprising a polymer containing structural units derived from a norbornene-based monomer and a filler composition, the filler composition comprising a flake-like filler and a binder, and exhibiting a weight loss rate of 1.4% or less under a nitrogen atmosphere at 280°C. Using such a resin composition, pellets with excellent appearance can be formed. In this specification, "norbornene-based monomer" refers to a monomer having a norbornene skeleton. In this specification, "flake-like filler" refers to a filler having two opposing main surfaces and having an aspect ratio of 13 or greater, calculated as the ratio of the maximum diameter of the main surfaces to the thickness (the distance between the two main surfaces). Here, "two main surfaces" refers to the two surfaces of the filler having the largest areas. Furthermore, the shape of the two main surfaces of the flake-like filler, i.e., the planar shape of the flake-like filler, can be any shape. The two main surfaces may be flat or curved, and do not necessarily have to have the same shape. In this specification, the shapes of various fillers can be observed using an electron microscope. In this specification, the "weight loss rate" can be measured using the method described in the examples.

[0009] [2] The resin composition according to the above [1], wherein the filler composition is a granular inorganic filler. If the filler composition is a granular inorganic filler, the appearance of the produced pellets can be further improved.

[0010] [3] The resin composition according to [1] or [2], wherein the binder contains at least one of paraffin wax and inorganic particles. When the binder contains paraffin wax and / or inorganic particles, pellets with excellent appearance can be obtained, and the surface smoothness of the molded product can be improved.

[0011] [4] The resin composition according to any one of [1] to [3], wherein the platy filler contains at least one of boehmite and mica. If the platy filler contains boehmite and / or mica, the thermal dimensional stability of the resulting molded article can be improved.

[0012] [5] The resin composition according to any one of [1] to [4] above, wherein the content of the filler composition or the granular inorganic filler is 10 parts by mass or more and 60 parts by mass or less, based on 100 parts by mass of the total mass of the polymer and the filler composition or the granular inorganic filler. By using a resin composition in which the content of the filler composition or the granular inorganic filler falls within the above range, pellets with excellent appearance can be obtained. Furthermore, the thermal dimensional stability of the resulting molded article can be improved.

[0013] [6] The resin composition according to any one of [1] to [5], further comprising a granular filler. By using a resin composition containing a granular filler in addition to a norbornene-based polymer and a filler composition or a granular inorganic filler, it is possible to perform processing such as coloring of the resin composition and to improve the flowability of the resin composition.

[0014] [7] The resin composition according to [6], wherein the ratio of the average particle size of the granular filler to the average particle size of the plate-like filler is 1 / 10 or less. When the ratio of the average particle size of the granular filler / the average particle size of the plate-like filler is equal to or less than the above value, the resin composition can be processed, for example, by coloring, and the fluidity of the resin composition can be further improved.

[0015] [8] A molded article obtained by molding the resin composition according to any one of the above items [1] to [7]. The molded article obtained by molding any one of the above resin compositions has excellent surface smoothness and thermal dimensional stability.

[0016] [9] The molded article according to [8] above, wherein the linear expansion coefficient in the MD direction and the linear expansion coefficient in the TD direction are both 40 ppm / K or less. A molded article having a linear expansion coefficient in both the MD direction and the TD direction that is equal to or less than the above value is said to have excellent thermal stability and is therefore preferred. In this specification, the MD (machine direction) direction refers to the direction parallel to the flow of the resin composition when producing the molded article, and the TD (transverse direction) direction refers to the direction perpendicular to the MD direction. The MD direction and the TD direction can be identified by observing the molded article itself. For example, when a gate mark is found in a molded article that is approximately rectangular in plan view, the extension direction of the side where the gate mark exists when the molded article is viewed in plan can be identified as the TD direction, and the direction perpendicular to the TD direction can be identified as the MD direction. Furthermore, for example, when a gate mark is found in a molded body of a substantially circular shape (such as a lens shape), the tangential direction of the substantially circle at the center of the gate mark when the molded body is viewed in plan can be identified as the TD direction, and the direction perpendicular to the TD direction can be identified as the MD direction. In this specification, the "linear expansion coefficient" in the MD direction and the TD direction of the molded body can be measured using the method described in the Examples.

[0017]

[10] The molded article according to [8] or [9], wherein the ratio of the linear expansion coefficient in the MD direction to the linear expansion coefficient in the TD direction is 0.8 to 1.2. A molded article having a ratio of the linear expansion coefficient in the MD direction to the linear expansion coefficient in the TD direction within the above range is preferred because it has small anisotropy in thermal dimensional stability.

[0018]

[11] The molded article according to any one of [8] to

[10] above, which has a water absorption rate of 0.05% by mass or less after immersion in water at 23°C for 24 hours as measured in accordance with ASTM D 570. A molded article having the water absorption rate of the above value or less is preferable because it has excellent water absorption resistance.

[0019]

[12] The molded article according to any one of [8] to

[11] above, having an arithmetic surface roughness Ra of 10 nm or less. A molded article having an arithmetic surface roughness Ra of the above value or less is preferable because it has excellent surface smoothness. In this specification, the "arithmetic surface roughness Ra" of the molded article can be measured using the method described in the examples.

[0020]

[13] The molded article according to any one of [8] to

[12] above, which is for use in a mirror.

[0021]

[14] A method for producing a resin composition, comprising the steps of kneading a flake-like filler and a binder to obtain a filler composition having a weight loss rate of 1.4% or less under a nitrogen atmosphere at 280°C, and kneading the filler composition with a polymer containing structural units derived from a norbornene-based monomer. Using the resin composition obtained by this production method, pellets with excellent appearance can be obtained. Furthermore, by kneading the flake-like filler and the binder to obtain a filler composition, the efficiency of kneading the filler into the polymer can be improved, thereby improving productivity.

[0022]

[15] The method for producing a resin composition according to the above

[14] , wherein the filler composition is a granular inorganic filler.

[0023]

[16] The method for producing a resin composition according to the above

[14] or

[15] , wherein the binder contains at least one of paraffin wax and inorganic particles. When the binder contains paraffin wax and / or inorganic particles, pellets with excellent appearance can be obtained.

[0024]

[17] The method for producing a resin composition according to any one of

[14] to

[16] above, wherein the platy filler contains at least one of boehmite and mica. If the platy filler contains boehmite and / or mica, the appearance of the resulting pellets can be further improved.

[0025]

[18] The method for producing a resin composition according to any one of

[14] to

[17] above, wherein the amount of the filler composition or the granular inorganic filler kneaded is 10 parts by mass or more and 60 parts by mass or less, based on 100 parts by mass of the total mass of the polymer and the filler composition or the granular inorganic filler. By using a resin composition produced with a filler composition or granular inorganic filler content within the above range, the appearance of the resulting pellets can be further improved. Furthermore, the thermal dimensional stability of the resulting molded product can be improved.

[0026]

[19] The method for producing a resin composition according to any one of

[14] to

[18] above, wherein a granular filler is further added and kneaded in the step of kneading the polymer with the filler composition or the granular inorganic filler. By using a resin composition produced by adding the granular filler to the norbornene-based polymer and the filler composition or the granular inorganic filler, it is possible to perform processing such as coloring of the resin composition and to improve the fluidity of the resin composition.

[0027]

[20] The method for producing a resin composition according to the above

[19] , wherein the ratio of the average particle size of the granular filler to the average particle size of the plate-like filler is 1 / 10 or less. When the ratio of the average particle size of the granular filler / the average particle size of the plate-like filler is equal to or less than the above value, the resin composition can be processed, for example, by coloring, and the fluidity of the produced resin composition can be further improved.

[0028] According to the present invention, it is possible to provide a resin composition which produces pellets with excellent appearance, a molded article using the same, and a method for producing the resin composition.

[0029] Hereinafter, embodiments of the present invention will be described in detail. The resin composition and the method for producing the resin composition of the present invention can be used to produce the molded article of the present invention. Furthermore, the molded article of the present invention can be used, without particular limitation, for example, as a mirror mounted on a projector, a head-up display, a lens housing, a housing for a home appliance, a structural member such as a screw or a bolt, etc. The molded article of the present invention has a stable shape and can therefore be used as a substitute for glass, metal, or ceramic members.

[0030] (Resin Composition) The resin composition of the present invention is required to contain a norbornene-based polymer and a filler composition, and may contain optional components as required.

[0031] The resin composition of the present invention contains a norbornene-based polymer and a filler composition, and exhibits a weight loss rate of 1.4% or less at 280°C in a nitrogen atmosphere. Therefore, by using the resin composition, a molded article having excellent pellet appearance can be produced.

[0032] <Norbornene-Based Polymer> The norbornene-based polymer is a polymer obtained by polymerizing a norbornene-based monomer, which is a monomer having a norbornene skeleton, or a hydrogenated product thereof.

[0033] Examples of norbornene-based polymers include ring-opening polymers of norbornene-based monomers, ring-opening polymers of norbornene-based monomers and other monomers copolymerizable therewith, hydrogenated products of these ring-opening polymers, addition polymers of norbornene-based monomers, and addition polymers of norbornene-based monomers and other monomers copolymerizable therewith.The norbornene-based polymers may be used singly or in combination of two or more.

[0034] Norbornene-based monomers include bicyclo[2.2.1]hept-2-ene (common name: norbornene) and its derivatives (those having a substituent on the ring), tricyclo[4.3.0]hept-2-ene (common name: norbornene), and １，６ .1 ２，５ ]deca-3,7-diene (trivial name: dicyclopentadiene) and its derivatives (those having a substituent on the ring), tetracyclo[9.2.1.0 ２，１０ .0 ３，８ ]tetradeca-3,5,7,12-tetraene, (methanotetrahydrofluorene: also called 1,4-methano-1,4,4a,9a-tetrahydrofluorene) and its derivatives (those having a substituent on the ring), tetracyclo[4.4.1 ２，５ .1 ７，１０.0]dodec-3-ene (common name: tetracyclododecene) and its derivatives (those having a substituent on the ring). Examples of the substituent include an alkyl group, an alkylene group, a vinyl group, an alkoxycarbonyl group, an alkylidene group, etc. Examples of the norbornene-based monomer having a substituent include 8-methoxycarbonyl-tetracyclo[4.4.0.1 ２，５ .1 ７，１０ ] dodec-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo[4.4.0.1 ２，５ .1 ７，１０ ] dodec-3-ene, 8-ethylidene-tetracyclo[4.4.0.1 ２，５ .1 ７，１０ ]dodec-3-ene, and the like, but are not limited thereto.

[0035] Other monomers that can be ring-opening copolymerized with norbornene-based monomers include monocyclic olefin-based monomers such as cyclohexene, cycloheptene, cyclooctene, and derivatives thereof (having a substituent on the ring). Examples of the substituents include the same as those shown as the substituents on norbornene-based monomers.

[0036] Other monomers that can be addition-copolymerized with norbornene-based monomers include α-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-pentene, and 1-hexene, and derivatives thereof (having a substituent); cycloolefins and derivatives thereof (having a substituent on the ring), such as cyclobutene, cyclopentene, cyclohexene, and cyclooctene; and non-conjugated dienes, such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and 1,7-octadiene. Among these, α-olefins are preferred, and ethylene is particularly preferred. Examples of the substituents include the same as those shown as the substituents for norbornene-based monomers.

[0037] Ring-opening polymers of norbornene-based monomers or ring-opening polymers of norbornene-based monomers and other monomers copolymerizable therewith can be synthesized by polymerizing the monomer components in the presence of a known ring-opening polymerization catalyst. Examples of the ring-opening polymerization catalyst include catalysts comprising a halide of a metal such as ruthenium or osmium, a nitrate or an acetylacetone compound, and a reducing agent, and catalysts comprising a halide or an acetylacetone compound of a metal such as titanium, zirconium, tungsten, or molybdenum, and an organoaluminum compound.

[0038] The hydrogenated ring-opened polymer of a norbornene monomer can usually be obtained by adding a known hydrogenation catalyst containing a transition metal such as nickel or palladium to a polymerization solution of the ring-opened polymer and hydrogenating the carbon-carbon unsaturated bonds. The hydrogenation rate is preferably 90% or more, more preferably 95% or more, and even more preferably 99% or more. In this specification, the "hydrogenation rate" can be measured using the method described in the Examples.

[0039] An addition polymer of a norbornene-based monomer or an addition polymer of a norbornene-based monomer and another monomer copolymerizable therewith can be synthesized by polymerizing the monomer components in the presence of a known addition polymerization catalyst, such as a catalyst comprising a titanium, zirconium, or vanadium compound and an organoaluminum compound.

[0040] From the viewpoint of improving the heat resistance and rigidity of the resulting pellets, the proportion of the norbornene-derived structural units contained in the norbornene-based polymer is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 70% by mass or more and 100% by mass or less, where the total amount of all structural units contained in the norbornene-based polymer is 100% by mass.

[0041] The weight-average molecular weight (Mw) of the norbornene-based polymer is not particularly limited, but is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 10,000 or more, and particularly preferably 20,000 or more, and is preferably 1,000,000 or less, and more preferably 500,000 or less. The molecular weight distribution (Mw / Mn) of the norbornene-based polymer is not particularly limited, but is preferably 1 or more and 4 or less, more preferably 1.5 or more and 3.5 or less. In this specification, the "weight-average molecular weight (Mw)" and "number-average molecular weight (Mn)" of a polymer such as a norbornene-based polymer can be measured using the method described in the Examples.

[0042] The proportion of the norbornene polymer contained in the resin composition of the present invention is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, and preferably 90 parts by mass or less, and more preferably 70 parts by mass or less, per 100 parts by mass of the total mass of the polymer and a filler composition described below. When the proportion of the norbornene monomer contained in the resin composition of the present invention is not more than the above upper limit, a molded product excellent in thermal dimensional stability and small anisotropy in thermal dimensional stability can be obtained, and when it is not less than the above lower limit, the resin composition has excellent moldability.

[0043] <Filler Composition> The filler composition is also referred to as a granular inorganic filler. The granular inorganic filler may be a granulated product of a plate-like inorganic filler and a binder. Hereinafter, the filler composition will be described as a granular inorganic filler. The granular inorganic filler must contain a plate-like filler and a binder, and may contain optional components as needed. For example, a silane coupling agent having a vinyl group, an amino group, an epoxy group, an isocyanate group, or the like may be added as an optional component to improve dispersibility. When a silane coupling agent is added, the amount is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, more preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and more preferably 3 parts by mass or less, based on 100 parts by mass of the plate-like filler. Adding a silane coupling agent within this range can improve the dispersibility of the plate-like filler in the resin. Using these reduces gas generation during heat kneading, allowing for the formation of pellets with excellent shape stability, as described below. Furthermore, by kneading the flake-like filler with the binder to form a granular inorganic filler, the efficiency of kneading the filler into the polymer can be improved, thereby improving productivity.

[0044] The granular inorganic filler must have a weight loss rate of 1.4% or less under a nitrogen atmosphere at 280°C, preferably 0.75% or less, and more preferably 0.65% or less. The lower limit of the weight loss rate is not particularly limited and may be 0%. If the weight loss rate is less than the above upper limit, outgassing during kneading with the polymer is reduced, foaming on the pellet surface is suppressed, and the appearance of the pellets can be improved. Furthermore, if the weight loss rate is less than the above upper limit, the dimensions of the generated pellets can be made uniform, i.e., the shape stability of the pellets can be improved. This is because the reduced outgassing during kneading can make the thickness of the strands emerging from the kneading device uniform and prevent the strands from breaking. Cutting such strands to generate pellets and ensuring uniform dimensions of the generated pellets makes it easier to load a constant amount of pellets into a molding machine. This improves productivity in the production of molded articles. Regarding the appearance and shape stability of the pellets, conventional resin compositions have the problem of being hygroscopic like water-soluble substances. In addition, gas is generated by decomposition during high-temperature processing, causing the resin melt discharged from the kneading device to foam, which reduces productivity due to breakage during strand generation and causes poor appearance such as irregular shapes in the generated pellets, leaving room for improvement. Furthermore, if the weight loss rate is not more than the above upper limit, good releasability from a mold can be achieved when a molded product such as a mirror is formed.

[0045] The proportion of the granular inorganic filler contained in the resin composition of the present invention is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and preferably 60 parts by mass or less, and more preferably 55 parts by mass or less, based on 100 parts by mass of the total mass of the polymer and the granular inorganic filler. If the proportion of the granular inorganic filler contained in the resin composition of the present invention is within the above range, it is possible to reduce gas generation during heat kneading and obtain pellets with even better shape stability. In addition, it is possible to improve the thermal dimensional stability of the resulting molded product.

[0046] <<Flat-Like Filler>> The platy filler is a filler having an aspect ratio of 13 or more. Here, the average aspect ratio of the platy filler is preferably 15 or more, more preferably 18 or more, preferably 80 or less, more preferably 75 or less, even more preferably 60 or less, still more preferably 45 or less, and particularly preferably 30 or less. If the average aspect ratio of the platy filler is within the above-mentioned range, the thermal dimensional stability of the obtained molded body can be further improved. Note that the "average aspect ratio" of the platy filler means the arithmetic mean diameter determined by observation with an electron microscope, and can be measured in more detail using the method described in the examples.

[0047] The average particle size of the platy filler is preferably 1 μm or more, more preferably 2 μm or more, and is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. If the average particle size of the platy filler is within the above-mentioned range, the thermal dimensional stability of the obtained molded article can be further improved.

[0048] Here, the shape of the flake-like filler in plan view is not particularly limited as described above, and may be, for example, a polygon, a circle, an ellipse, or a shape similar to any of these shapes.

[0049] The flake-like filler preferably has a hexagonal shape in plan view. The hexagonal shape in plan view is not limited to a regular hexagon, and any approximate hexagon that is recognized as having six corners will suffice, and as long as it has little anisotropy, the lengths of the sides connecting the corners may be slightly different, or at least one of the sides may be curved.

[0050] The plate-like filler is preferably an inorganic filler. From the viewpoint of further improving the appearance of the resulting pellets, preferred examples of the plate-like filler include boehmite and mica, with boehmite being more preferred. These may be used alone or in combination of two or more.

[0051] The proportion of the platy filler contained in the resin composition of the present invention is preferably 91 parts by mass or more, more preferably 95 parts by mass or more, and preferably 99 parts by mass or less, more preferably 98 parts by mass or less, per 100 parts by mass of the granular inorganic filler. If the proportion of the platy filler contained in the resin composition of the present invention is within the above range, it is possible to reduce gas generation during heat kneading and obtain pellets with even better shape stability. In addition, it is possible to improve the thermal dimensional stability of the resulting molded product.

[0052] <<Binder>> The binder is not particularly limited and can contain at least one selected from the group consisting of paraffin wax, inorganic particles, metal soap, and resins such as polyacrylic acid resins or stearic acid resins. Among these, it is preferable that the binder contains at least one of paraffin wax and inorganic particles. The paraffin wax is not particularly limited and can be one whose decomposition onset temperature is equal to or higher than the kneading temperature with the polymer. For example, paraffin waxes whose decomposition onset temperature is 280°C or higher, specifically, Hicol (registered trademark) K-350, LUVAX (registered trademark)-2191, etc. can be mentioned. As the inorganic particles, for example, a mixture containing 2 parts by mass of inorganic particles per 100 parts by mass of the plate-like filler and having a bulk density of 0.3 g / cm ３Inorganic particles having the above properties and a weight loss rate of the mixture of 0.75 or less when maintained at 280°C for 80 minutes are preferred. Furthermore, the inorganic particles preferably form a sol or gel with a liquid such as water. Specific examples of inorganic particles include aluminum hydroxide gel, alumina hydrates such as pseudoboehmite, transition aluminas in crystalline phases such as gamma, delta, theta, and chi phases, amorphous silicas such as precipitated silica, silica sol, colloidal silica, and silica nanoparticles, calcium compounds such as calcium hydroxide, calcium oxide, and calcium carbonate, magnesium compounds such as magnesium hydroxide, magnesium oxide, and magnesium carbonate, titanium compounds such as titanium hydroxide and titanium oxide, and zirconium oxide. Among these, aluminum hydroxide gel, alumina hydrates such as pseudoboehmite, and amorphous silicas such as silica nanoparticles are particularly preferred. Two or more of these may also be mixed and used. Examples of stearic acid-based resins include ethylene bisstearic acid amide, such as Kaowax EB-FF (registered trademark). As the metallic soap, zinc stearate, which has the lowest water absorption among metallic soaps, is preferred, and examples thereof include Zinc Stearate S (registered trademark). These binders can be used alone or in combination of two or more.

[0053] The paraffin wax preferably has a decomposition onset temperature of 280° C. or higher, more preferably 300° C. or higher. The upper limit of the decomposition onset temperature is not particularly limited, but is generally 350° C. or lower. When the decomposition onset temperature of the paraffin wax is equal to or higher than the above lower limit, the generation of bubbles is reduced when the composition is heated, and the appearance of the resulting pellets can be further improved.

[0054] Among the above, aluminum hydroxide gel and paraffin wax having a decomposition starting temperature of 300° C. or higher are preferred as binders from the viewpoint of further improving the appearance of the resulting pellets.

[0055] The proportion of binder contained in the granular inorganic filler is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less per 100 parts by mass of the plate-like filler. If the proportion is less than 0.5 parts by mass per 100 parts by mass of the plate-like filler, granules are not produced. If the proportion is more than 5 parts by mass per 100 parts by mass of the plate-like filler, moisture is easily adsorbed due to the large specific surface area of ​​the inorganic particles, increasing the amount of gas generated during resin molding, resulting in molding defects and performance degradation. If the proportion of binder contained in the granular inorganic filler is within the above range, the granular inorganic filler can be formed well during production. When the binder is inorganic particles, if the content of the binder is below the above upper limit, the weight loss rate of the granular inorganic filler at 280°C in a nitrogen atmosphere can be reduced. On the other hand, when the binder is paraffin wax, as long as the binder content is equal to or greater than the above-mentioned lower limit, the weight loss rate of the granular inorganic filler in a nitrogen atmosphere at 280°C can be reduced. Although the mechanism behind this is unclear, when the binder is inorganic particles, it is presumed that, if the amount added is within an appropriate range, granulation reduces the specific surface area, resulting in only a small amount of adsorbed moisture, and the weight loss rate is reduced due to the reduction in moisture contained in the inorganic particles. Furthermore, when the binder is paraffin wax, it is presumed that the content of paraffin wax increases, resulting in a relative reduction in moisture contained in the plate-like filler, etc., and therefore a reduction in the weight loss rate of the granular inorganic filler.

[0056] <Optional Components> Components that may be optionally contained in the resin composition other than the norbornene-based polymer and the granular inorganic filler are not particularly limited, and may include fillers other than the above-mentioned flake-like fillers (other fillers), antioxidants, moisture-resistant agents, release agents, flame retardants, antibacterial agents, wood flour, coupling agents, plasticizers, colorants, lubricants, silicone oils, foaming agents, surfactants, thermoplastic elastomers, infrared absorbers, light resistance stabilizers, etc. The other components may be used alone or in combination of two or more.

[0057] The other fillers are not particularly limited as long as they have a shape other than a plate shape, and may have any shape such as granular or needle-like.

[0058] In addition, from the viewpoint of processing the resin composition, such as coloring, and improving the fluidity of the resin composition, the resin composition preferably contains a granular filler. In this specification, "granular filler" refers to a filler having an aspect ratio, calculated as the ratio of the maximum diameter to the minimum diameter, of less than 13. The granular filler does not function as a binder for the plate-like filler, and while the binder has the effect of coagulating the plate-like filler particles together, the granular filler functions independently, such as for coloring and improving the fluidity of the resin.

[0059] Here, the granular filler preferably has an average aspect ratio of 5 or less, more preferably 3 or less, and even more preferably 2 or less. If the aspect ratio of the granular filler is equal to or less than the above value, the fluidity of the resin composition can be further increased. Furthermore, the aspect ratio of the granular filler is 1 or more, and may be greater than 1. In this specification, the "average aspect ratio" of the granular filler means the arithmetic mean diameter determined by observation with an electron microscope, and more specifically, it can be measured using the method described in the examples.

[0060] The granular filler is not particularly limited, and carbon-based granular fillers and non-carbon-based granular fillers can be used. Examples of carbon-based granular fillers include graphite such as artificial graphite, scaly graphite, exfoliated graphite, natural graphite, acid-treated graphite, expandable graphite, and expanded graphite; carbon black; and the like. Examples of non-carbon-based granular fillers include titanium oxide, alumina, talc, calcium carbonate, and zinc oxide. These granular fillers can be used alone or in combination of two or more.

[0061] Among the above, carbon black and titanium oxide are preferred as the particulate filler from the viewpoint of improving the fluidity of the resin composition, and carbon black is more preferred. Carbon black is also useful for producing a black-colored molded product.

[0062] From the viewpoint of enhancing the fluidity of the resin composition, the granular filler preferably has an average particle size of 0.01 μm or more, more preferably 0.015 μm or more, and preferably 0.1 μm or less, more preferably 0.08 μm or less, and even more preferably 0.07 μm or less. Also, from the viewpoint of further enhancing the fluidity of the resin composition, the ratio of the average particle size of the granular filler to the average particle size of the plate-like filler is preferably 1 / 10 or less, more preferably 1 / 20 or less, and even more preferably 1 / 50 or less.

[0063] The proportion of the granular filler contained in the resin composition of the present invention is not particularly limited, and is, for example, 0 to 0.6 parts by mass, where the total mass of the polymer and the granular inorganic filler is 100 parts by mass. From the viewpoint of obtaining sufficient fluidity of the resin composition, the proportion of the granular filler contained in the resin composition is preferably 0.05 parts by mass or more, and more preferably 0.3 parts by mass or more.

[0064] (Method for Producing Resin Composition) <Method for Preparing Resin Composition> The resin composition of the present invention is not particularly limited and can be prepared, for example, by a method including the steps of kneading the above-described flake-like filler and binder to obtain a filler composition having a weight loss rate of 1.4% or less under a nitrogen atmosphere at 280°C, and thoroughly mixing the norbornene-based polymer, the filler composition, and any optional components used as needed. Examples of such a method include feeding a mixture of the above components to a melt kneader and kneading the norbornene-based polymer in a molten state. The resulting resin composition may be molded into pellets or the like by any method. The types, proportions, and physical properties of the kneaded substances are preferably as described in the "Resin Composition" section. As described above in the "Filler Composition" section of the "Resin Composition" section, the filler composition is also referred to as a granular inorganic filler. Using the resin composition obtained by such a production method, a molded product with excellent pellet appearance can be formed. Furthermore, by kneading the flake-like filler with the binder to form a granular inorganic filler, the efficiency of kneading the filler into the polymer can be improved, thereby improving productivity.

[0065] For kneading, a melt kneader such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader, a roll, or a feeder ruder can be used. The kneading temperature is preferably 200° C. or higher, more preferably 240° C. or higher, and preferably 400° C. or lower, more preferably 300° C. or lower. In kneading, the components may be kneaded all at once, or may be kneaded by adding them in several portions.

[0066] (Molded Article) The molded article of the present invention is obtained by molding the resin composition of the present invention described above. That is, the norbornene-based polymer and filler composition, as well as the optional components used as needed, contained in the molded article of the present invention are those described above in the "Resin Composition" section. The relationship between the contents (content ratio) and attributes of the norbornene-based polymer, filler composition, and optional components contained in the molded article of the present invention are generally the same as the relationship between the contents (content ratio) and attributes of those components in the resin composition. Furthermore, since the molded article of the present invention is formed from the resin composition of the present invention described above, the resin composition outgassing is reduced, foaming on the surface of the molded article is suppressed, and the molded article has an excellent appearance.

[0067] The molding method for producing the molded article of the present invention is not particularly limited and can be appropriately selected from known molding methods depending on the desired shape of the molded article. Examples of such known molding methods include extrusion molding, injection molding, inflation molding, blow molding, extrusion blow molding, injection blow molding, press molding, vacuum molding, powder slush molding, calendar molding, foam molding, thermoforming, etc. Among these, injection molding is preferably used as the molding method.

[0068] Furthermore, a molding method (heat-and-cool molding) may be employed in which the temperature of the mold cavity interior surface during filling is set to a temperature at which the resin composition can be plastically deformed, cooling is initiated between the completion of filling and the completion of pressure holding, and the product is removed after being sufficiently cooled. By performing heat-and-cool molding, the arithmetic surface roughness Ra of the molded product can be reduced while improving its appearance. As a result, a high-quality mirror can be provided, particularly when a mirror is formed as the molded product.

[0069] <Properties of Molded Article> The molded article of the present invention can be formed into any shape depending on its application. The molded article of the present invention can have the following properties, for example.

[0070] <<Linear expansion coefficient>> The linear expansion coefficient of the molded body in the TD direction and MD direction is preferably 40 ppm / K or less, more preferably 35 ppm / K or less, and even more preferably 32 ppm / K or less. A molded body having a linear expansion coefficient in both the MD direction and the TD direction that is equal to or less than the above value is preferred because it has excellent thermal dimensional stability. The lower limit of the linear expansion coefficient in the TD direction and the MD direction is not particularly limited, but is, for example, 1 ppm / K or more.

[0071] Furthermore, the ratio of the linear expansion coefficient in the MD direction to the linear expansion coefficient in the TD direction of the molded article is preferably 0.8 or more, more preferably 0.9 or more, and preferably 1.2 or less, more preferably 1.0 or less. A molded article having a ratio of the linear expansion coefficient in the MD direction / linear expansion coefficient in the TD direction within the above range is preferred because it has little anisotropy in terms of thermal dimensional stability.

[0072] <<Water Absorption Rate>> The norbornene polymer contained in the resin composition used to prepare the molded article has excellent hydrophobicity, and therefore the molded article has good water absorption resistance. The molded article of the present invention has a water absorption rate after immersion in water at 23°C for 24 hours, measured in accordance with ASTM D570, of preferably 0.05% by mass or less, more preferably 0.03% by mass or less, and even more preferably 0.01% by mass or less. A molded article having a water absorption rate of the above value or less is preferred because it has excellent water absorption resistance. The lower limit of the water absorption rate is not particularly limited, but is, for example, 0.001% by mass or more.

[0073] <<Arithmetic Surface Roughness Ra>> The molded body preferably has an arithmetic surface roughness Ra of 10 nm or less, more preferably 8 nm or less. A molded body having an arithmetic surface roughness Ra of the above value or less is preferable because it has excellent surface smoothness. The lower limit of the arithmetic surface roughness Ra is not particularly limited, but is, for example, 1 nm or more.

[0074] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the following description, "%" and "parts" representing amounts are based on mass unless otherwise specified. Furthermore, in a polymer produced by polymerizing multiple types of monomers, the proportion of a monomer unit formed by polymerizing a certain monomer in the polymer usually coincides with the ratio (feed ratio) of that certain monomer to all monomers used in the polymerization of the polymer, unless otherwise specified. In the examples and comparative examples, various measurements and evaluations were carried out by the following methods.

[0075] (Measurement and Evaluation of Physical Properties) <Hydrogenation Rate> Using deuterated chloroform as a solvent, １ H-NMR measurement was carried out, and the hydrogenation rate in the hydrogenation reaction was calculated.

[0076] <Molecular Weight> The number average molecular weight (Mn) and weight average molecular weight (Mw) were measured as values ​​converted to standard polyisoprene by gel permeation chromatography (GPC) using cyclohexane as a solvent. The molecular weight distribution (Mw / Mn) was calculated from these values. For GPC, an HLC8120GPC manufactured by Tosoh Corporation was used. As standard polyisoprene, a total of 10 standard polyisoprenes manufactured by Tosoh Corporation with Mw = 602, 1390, 3920, 8050, 13800, 22700, 58800, 71300, 109000, and 280000 were used. The measurement was carried out using three columns connected in series, TSKgel G5000HXL, TSKgel G4000HXL and TSKgel G2000HXL manufactured by Tosoh Corporation, at a flow rate of 1.0 ml / min, a sample injection volume of 100 μml and a column temperature of 40°C.

[0077] <Properties of Plate-Like Fillers> The resin compositions prepared in the Examples and Comparative Examples were burned at 550°C to remove the resin components, and then a solvent was added to the resulting ash to elute the filler components. The resulting ash was then applied to the surface of an observation substrate, making the filler components observable. Next, properties such as the aspect ratio were confirmed using a scanning electron microscope (SEM) to determine whether the various filler components were plate-like. Then, the maximum diameter and thickness of 50 randomly selected plate-like fillers were measured, and the aspect ratio was calculated. The arithmetic mean value of the maximum diameters of these 50 plate-like fillers was taken as the average particle size, and the arithmetic mean value of the aspect ratios was taken as the average aspect ratio.

[0078] <Average particle size of granular filler> The resin compositions prepared in the examples and comparative examples were burned at 550 ° C to remove the resin components, and then a solvent was added to the resulting ash to dissolve the granular filler. The granular filler was then applied to the surface of an observation substrate, making each granular filler observable. The particle sizes of 50 randomly selected granular fillers were then individually observed using a scanning electron microscope (SEM). Circles were drawn on the images of each granular filler using a planar measurement tool, and the maximum and minimum diameters of the drawn circles were measured by linear measurement. The arithmetic mean of the maximum and minimum diameters was taken as the particle size of the granular filler, and the average value of the particle sizes of the 50 granular fillers was taken as the average particle size of the granular filler.

[0079] <Binder Decomposition Initiation Temperature> The decomposition initiation temperature of the binder component was measured using a thermogravimetric analyzer (manufactured by Hitachi High-Tech Science Corporation, product name "TA7000"). Specifically, the measurement temperature was increased in an air atmosphere measurement environment, and the weight of the binder (W (g)) was measured. Based on the obtained data, a graph (thermogravimetric curve) was created in which the elapsed time after the start of measurement was plotted on the horizontal axis (X coordinate axis) and the weight of the binder (W (g)) on the vertical axis (Y coordinate axis). The temperature at which a weight loss of 5% occurred relative to the initial weight of the binder was determined as the decomposition initiation temperature.

[0080] <Weight Loss Rate> The weight loss rate of the granular inorganic filler at 280°C under a nitrogen atmosphere was measured using a thermogravimetric analyzer (manufactured by Hitachi High-Tech Science Corporation, product name "TA7000"). Specifically, 5 mg of sample was weighed into an open pan container, and held for 60 minutes at a measurement temperature of 280°C under a nitrogen atmosphere, and the weight (W (g)) of the granular inorganic filler was measured. If the holding time at 280°C is short, such as 20 minutes or less, there is a large fluctuation in the numerical value and accurate values ​​cannot be obtained. The holding time is not limited to 60 minutes depending on the substance and content, but a time sufficient for the amount of weight loss to become constant is preferable. Based on the obtained data, the weight loss rate (TG (%)) of the granular inorganic filler at 280°C under a nitrogen atmosphere was calculated using the following formula (1): TG (%) = {(W ２８０ -W ０ ) / W ０}×100...(1) [In formula (1), W ０ is the weight (g) of the granular inorganic filler before thermogravimetric analysis, and W ２８０ is the weight (g) of the granular inorganic filler after a predetermined time has elapsed at 280°C.

[0081] <Linear expansion coefficient> Test pieces measuring 10 cm in length, 5 cm in width, and 5 cm in thickness were cut from the molded articles prepared in the Examples and Comparative Examples so that the 10 cm length was in the TD direction, and the linear expansion coefficient (ppm / K) specified in ASTM E831 was measured. This measurement was performed a total of three times, and the average of these measurements was taken as the linear expansion coefficient in the TD direction. Test pieces measuring 10 cm in length, 5 cm in width, and 5 cm in thickness were cut from the molded articles prepared in the Examples and Comparative Examples so that the 10 cm length was in the MD direction, and the linear expansion coefficient (ppm / K) specified in ASTM E831 was measured. This measurement was performed a total of three times, and the average of these measurements was taken as the linear expansion coefficient in the MD direction. The ratio of the linear expansion coefficient in the MD direction to the linear expansion coefficient in the TD direction was then calculated.

[0082] <Water Absorption Rate> The molded articles produced in the examples and comparative examples were immersed in water at 23° C. for 24 hours and then their water absorption rates were measured in accordance with ASTM D570.

[0083] <Arithmetic surface roughness Ra> The arithmetic surface roughness Ra of the molded bodies produced in the examples and comparative examples was measured using a white light interferometer (NewView (registered trademark) series, manufactured by ZYGO Corporation). The measurement magnification was adjusted so that the measurement field was 1.82 mm x 1.36 mm, and measurements were taken at five arbitrary points near the center of the measurement sample, and the average value was taken as the arithmetic surface roughness Ra. The results were evaluated according to the following criteria. In addition, if the four corners of the three-dimensional image of the measurement results were not flat (the unevenness was greater than that of the center), the results were excluded and the average value was calculated. In addition, in order to correct for large waviness on the surface, the analysis was performed in Cylinder mode. A+: Arithmetic surface roughness Ra is 10 nm or less. A: Arithmetic surface roughness Ra is more than 10 nm.

[0084] <Appearance of pellets> The pelletized resin compositions produced in the examples and comparative examples were visually inspected, and the appearance of the pellets was judged according to the following criteria. A: The pellets maintained the same shape and appearance as pellets without added filler. B: Particles were visible on the surface, but the pellets maintained the same shape as pellets without added filler. C: Particles were visible on the surface, and the edges of the pellets were chipped. D: Brittle, and the pellet shape was not maintained.

[0085] <Mold Releasability> The pelletized resin composition was dried by heating at 80°C for 4 hours, and then placed in an injection molding machine (manufactured by Fanuc Corporation, product name "Roboshot α-100B") and injection molded at a cylinder temperature of 270°C and a mold temperature of 135°C to obtain a plate-shaped molded product of 90 mm x 55 mm x 5 mm. This operation was continuously repeated, and if the molded product stuck to the mold two or more times in a row when the mold was released, it was considered to be a mold release failure and the number of moldings was recorded. A: Sticking occurs after 300 or more moldings. B: Sticking occurs after 100 or more but less than 300 moldings. C: Sticking occurs after 50 or more but less than 100 moldings. D: Sticking occurs after less than 50 moldings.

[0086] Example 1 Preparation of Resin Composition 100 g of boehmite ("BMF-520" manufactured by Kawai Lime Industry Co., Ltd., average aspect ratio: 20, average particle size: 5 μm) as a plate-like filler was placed in a soil mixer (model number KS-54, manufactured by Kansai Seisakusho Co., Ltd.) and stirred at 70 rpm while spraying 80 g of an aqueous suspension containing 3.8 parts by weight of paraffin wax ("Hicol (registered trademark) K-350" manufactured by Kaneda Co., Ltd., decomposition onset temperature 293°C) as a binder. The resulting mixture was dried at 120°C to produce a granular inorganic filler containing 3 parts by weight of paraffin wax. The weight loss rate of this granular inorganic filler was measured using the method described above. Thereafter, 60 parts of COP (ZEONOR (registered trademark) 1420R manufactured by Zeon Corporation) as a norbornene-based polymer and 40 parts of the granular inorganic filler were mixed, and then kneaded using a kneader (manufactured by Shibaura Machine Co., Ltd., product name "TEM-37") at 280°C and 150 rpm to obtain a pelletized resin composition. In the examples and comparative examples, the properties (average aspect ratio, average particle size, etc.) of the various fillers in the resin composition were the same as those at the time of charging. <Preparation of Molded Product> The pelletized resin composition was dried by heating at 80°C for 4 hours, and then placed in an injection molding machine (manufactured by Fanuc Corporation, product name "Roboshot α-100B") and injection molded at a cylinder temperature of 270°C and a mold temperature of 135°C to obtain a plate-shaped molded product measuring 90 mm x 55 mm x 5 mm. This molded product was subjected to various measurements and evaluations using the methods described above. The results are shown in Table 1.

[0087] (Examples 2-7 and 12-14, and Comparative Example 1) Various operations, measurements, and evaluations were carried out in the same manner as in Example 1, except that the types and amounts of the norbornene-based polymer, platy filler, binder, and granular filler were changed as shown in Tables 1 and 2. The granular filler was added when the norbornene-based polymer and the granular inorganic filler were mixed, and then kneading was performed. The results are shown in Tables 1 and 2.

[0088] Example 8 Preparation of Resin Composition 100 g of boehmite ("BMF-520" manufactured by Kawai Lime Industry Co., Ltd., average aspect ratio: 20, average particle size: 5 μm) as a plate-like filler was placed in a soil mixer (model number KS-54, manufactured by Kansai Seisakusho Co., Ltd.), and aluminum hydroxide gel (specific surface area: 64 m) as a binder was added while stirring at 70 rpm. ２ The mixture was stirred while spraying 120 g of an aqueous suspension (solids concentration 1.7 parts by weight, D50 of the subsequent component: 120 nm) containing aluminum hydroxide gel (1.7 parts by weight, average particle size: 19 μm, aluminum oxide content: 53%, loss on drying: 16%). The resulting mixture was dried at 120°C to prepare a granular inorganic filler containing 2 parts by weight of aluminum hydroxide gel. The weight loss rate of this granular inorganic filler was measured using the method described above. Subsequently, 60 parts of a norbornene-based polymer COP (ZEONOR (registered trademark) 1420R manufactured by Zeon Corporation) and 40 parts of the granular inorganic filler were mixed, and then kneaded at 280°C and 150 rpm using a kneader (manufactured by Shibaura Machine Co., Ltd., product name "TEM-37") to obtain a pelletized resin composition. In the examples, the properties (average aspect ratio, average particle size, etc.) of the various fillers in the resin composition were the same as those at the time of charging. <Preparation of Molded Article> The pelletized resin composition was dried by heating at 80°C for 4 hours, and then placed in an injection molding machine (manufactured by Fanuc Corporation, product name "Roboshot α-100B") and injection molded at a cylinder temperature of 270°C and a mold temperature of 135°C to obtain a flat plate-shaped molded article measuring 90 mm x 55 mm x 5 mm. This molded article was subjected to various measurements and evaluations using the methods described above. The results are shown in Table 2.

[0089] (Examples 9 to 11) Various operations, measurements, and evaluations were carried out in the same manner as in Example 8, except that the types and amounts of the flake filler, binder, and granular filler were changed as shown in Table 2. The granular filler was added when the norbornene-based polymer and the granular inorganic filler were mixed, and then kneading was performed. The results are shown in Table 2.

[0090] In Tables 1 and 2, "COC" refers to "APEL (registered trademark)" manufactured by Mitsui Chemicals, Inc., "LUVAX (registered trademark)-2191" refers to "LUVAX (registered trademark)-2191" manufactured by Nippon Seiro Co., Ltd. (decomposition starting temperature: 315°C), and "aluminum hydroxide gel" refers to a gel having a specific surface area of ​​64 m. ２ / g, average particle size: 19 μm, aluminum oxide content: 53%, loss on drying: 16%, "polymethyl methacrylate" refers to Aron (registered trademark) AS-1800 manufactured by Toagosei, "Unistar H-476" refers to "Unistar (registered trademark) H-476" manufactured by NOF Corporation, "polypropylene" refers to "Excellen (registered trademark)" manufactured by Sumitomo Chemical Co., Ltd., and "CB" refers to carbon black product number "CB#650B" manufactured by Mitsubishi Chemical Corporation.

[0091]

[0092]

[0093] Tables 1 and 2 show that pellets with excellent appearance were produced in Example 1-14, which used a resin composition containing a norbornene-based polymer and a filler composition (granular inorganic filler), where the filler composition contained a plate-like filler and a binder and had a weight loss rate of 1.4% or less under a nitrogen atmosphere at 280°C.

[0094] According to the present invention, it is possible to provide a resin composition which produces pellets with excellent appearance, a molded article using the same, and a method for producing the resin composition.

Claims

1. A resin composition comprising a polymer containing a structural unit derived from a norbornene-based monomer and a filler composition, the filler composition comprising a plate-like filler and a binder, and having a weight loss rate of 1.4% or less in a nitrogen atmosphere at 280°C.

2. The resin composition according to claim 1, wherein the filler composition is a granular inorganic filler.

3. The resin composition according to claim 2, wherein the binder comprises at least one of paraffin wax and inorganic particles.

4. The resin composition according to claim 2, wherein the platy filler comprises at least one of boehmite and mica.

5. A resin composition according to claim 2, wherein the content of the granular inorganic filler is 10 parts by mass or more and 60 parts by mass or less, with the total mass of the polymer and the granular inorganic filler being 100 parts by mass.

6. The resin composition according to claim 2, further comprising a particulate filler.

7. The resin composition according to claim 6, wherein the ratio of the average particle size of said granular filler to the average particle size of said plate-like filler is 1 / 10 or less.

8. A molded article obtained by molding the resin composition according to any one of claims 1 to 7.

9. The molded article according to claim 8, wherein the linear expansion coefficient in the MD direction and the linear expansion coefficient in the TD direction are both 40 ppm / K or less.

10. The molded article according to claim 8, wherein the ratio of the linear expansion coefficient in the MD direction to the linear expansion coefficient in the TD direction is 0.8 or more and 1.2 or less.

11. The molded article according to claim 8, which has a water absorption rate of 0.05% by mass or less after immersion in water at 23°C for 24 hours as measured in accordance with ASTM D570.

12. The molded article according to claim 8, having an arithmetic surface roughness Ra of 10 nm or less.

13. The molded article according to claim 8, which is for use as a mirror.

14. A method for producing a resin composition, comprising: a step of kneading a plate-like filler with a binder to obtain a filler composition having a weight loss rate of 1.4% or less under a nitrogen atmosphere at 280°C; and a step of kneading the filler composition with a polymer containing a structural unit derived from a norbornene-based monomer.

15. The method for producing a resin composition according to claim 14, wherein the filler composition is a granular inorganic filler.

16. The method for producing a resin composition according to claim 15, wherein the binder comprises at least one of paraffin wax and inorganic particles.

17. The method for producing a resin composition according to claim 15, wherein the plate-like filler comprises at least one of boehmite and mica.

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