Method for producing impact modifier

Abstract

To provide a method for producing an impact modifier that allows enhancement of impact resistance of a resin composition formed by kneading with a resin and allows suppression of non-uniform portions occurring in a molded article of the resin composition.SOLUTION: A method for producing an impact modifier by means of an extruder, the impact modifier being a melt-kneaded product of a composition containing a graft copolymer in which a side chain formed of a polymer of an ethylenically unsaturated monomer including styrene is bonded to a main chain formed of an ethylene-propylene-diene copolymer, and a styrenic polymer, the graft copolymer having an ethylene-propylene-diene copolymer ratio of 40 to 60 mass%, a content of the graft copolymer being 65 to 92.5 mass% based on a total mass of the graft copolymer and the styrenic polymer, and a temperature of a melt of the impact modifier discharged from the extruder being 310°C or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for making an impact modifier. [Background technology]

[0002] Modifiers containing rubber are used to improve the properties of engineering plastics such as polycarbonate. Patent Document 1 discloses a thermoplastic resin composition comprising a polycarbonate resin and a graft copolymer obtained by polymerizing, under suspension polymerization conditions, finely pulverized ethylene-propylene rubber and a compound consisting of an aromatic vinyl compound and a vinyl cyanide compound or an unsaturated carboxylic acid alkyl ester compound. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 59-066445 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a method for producing an impact resistance modifier that, when kneaded with a resin to form a resin composition, can improve the impact resistance of the resin composition and suppress the occurrence of non-uniform portions in a molded product of the resin composition. [Means for solving the problem]

[0005] The present disclosure provides the following [1] to [7]. [1] A method for producing an impact modifier using an extruder, The impact resistance modifier is a melt-kneaded product of a composition including a graft copolymer in which a side chain made of a polymer of an ethylenically unsaturated monomer containing styrene is bonded to a main chain made of an ethylene-propylene-diene copolymer, and a styrene-based polymer; The graft copolymer has an ethylene-propylene-diene copolymer ratio of 40 to 60 mass %, the content of the graft copolymer is 65 to 92.5 mass% based on the total mass of the graft copolymer and the styrene-based polymer; The method of manufacturing, wherein the temperature of the molten impact modifier when discharged from the extruder is 310°C or less. This method for producing an impact resistance modifier has the above-mentioned configuration, and thereby has the effect of producing an impact resistance modifier that can improve the impact resistance of the resin composition when kneaded with a resin to form a resin composition, and can suppress the occurrence of uneven portions in molded products of the resin composition. [2] The manufacturing method described in [1], wherein the extruder is provided with a temperature-controllable cylinder having a supply port and a discharge port, and one or more rotatable screws inserted into the cylinder. [3] The manufacturing method according to [2], wherein the temperature of the cylinder is 120 to 300° C. In this case, the diameter of the screw can be 15 to 65 mm, and the ratio of the length of the screw to the diameter of the screw (L / D) can be 35 to 60. [4] The manufacturing method according to [2] or [3], wherein the temperature of the cylinder is 220 to 300°C when the screw diameter is 15 mm or more and less than 35 mm, and 120 to 220°C when the screw diameter is 35 mm or more and 65 mm or less. [5] The manufacturing method according to any one of [2] to [4], wherein the rotation speed of the screw is 300 to 600 rpm. [6] The method according to any one of [1] to [5], wherein the pressure applied to the melt in the extruder is 3 to 7 MPa. [7] The method according to any one of [1] to [6], wherein the composition contains an antioxidant. [Effects of the Invention]

[0006] According to the present invention, a production method can be provided for producing an impact resistance modifier that, when kneaded with a resin to form a resin composition, can improve the impact resistance of the resin composition and can suppress the occurrence of non-uniform portions in a molded product of the resin composition. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic diagram illustrating an example of the internal structure of an extruder. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described, but the invention is not limited to this embodiment.

[0009] The impact modifier is a melt-kneaded composition containing a graft copolymer and a styrene-based polymer. The main chain of the graft copolymer is made of an ethylene-propylene-diene copolymer (hereinafter also referred to as "EPDM"), and side chains made of polymers of ethylenically unsaturated monomers are bonded to this main chain. Other side chains may be bonded to the main chain of the graft polymer, but it is preferable that only side chains made of polymers of ethylenically unsaturated monomers are bonded. One or more side chains made of polymers of ethylenically unsaturated monomers are present per molecule of EPDM, and when two or more side chains are present, the types and ratios of monomers constituting the polymers of ethylenically unsaturated monomers may be the same or different.

[0010] The proportion of ethylene in all monomers constituting EPDM can be, for example, 25 to 75 mass%, 25 to 60 mass%, 25 to 59.5 mass%, 29 to 75 mass%, 29 to 60 mass%, 29 to 59.5 mass%, 44 to 75 mass%, 44 to 60 mass%, or 44 to 59.5 mass%. When the proportion is 25 to 75 mass%, the impact resistance of the resin composition obtained by using the impact modifier is increased, and the effect of suppressing the occurrence of non-uniform parts (meaning lumps, undispersed matter, fisheyes, etc., hereinafter sometimes referred to as "lumps") in molded products of the resin composition is remarkable.

[0011] The proportion of propylene in all monomers constituting EPDM can be, for example, 20 to 50 mass%, 33 to 50 mass%, or 33 to 47 mass%. When the proportion is 20 to 50 mass%, the resin composition obtained by using the impact resistance modifier has high impact resistance, particularly at low temperatures.

[0012] The diene as a monomer constituting EPDM is preferably a non-conjugated diene. Examples of non-conjugated dienes include 5-ethylidene-2-norbornene, dicyclopentadiene, 1,4-hexadiene, 1,5-hexadiene, 2-methyl-1,5-hexadiene, 1,4-cycloheptadiene, and 1,5-cyclooctadiene, with 5-ethylidene-2-norbornene being preferred. One type of diene may be used alone, or two or more types may be used in combination.

[0013] The proportion of diene in all monomers constituting EPDM can be, for example, 5 to 15 mass%, 5 to 11 mass%, 5 to 9 mass%, 7 to 15 mass%, 7 to 11 mass%, 7 to 9 mass%, 7.5 to 15 mass%, 7.5 to 11 mass%, or 7.5 to 9 mass%. When the proportion is 5 to 15 mass%, the impact resistance of the resin composition obtained by using the impact resistance modifier is increased, and the effect of suppressing the generation of lumps is remarkable.

[0014] EPDM may be composed of monomer units consisting of ethylene, propylene, and a diene, or may contain other monomers as monomer units. The proportion of other monomers in the total monomers constituting EPDM may be 0 to 5 mass %, or 0 to 3 mass %. EPDM may be produced by a known method, or a commercially available product may be used.

[0015] The Mooney viscosity ML(1+4)125°C of the EPDM can be, for example, 50 to 80, 50 to 75, 50 to 70, 55 to 80, 55 to 75, 55 to 70, 60 to 80, 60 to 75, or 60 to 70. When the Mooney viscosity ML(1+4)125°C is 50 or higher, the impact resistance of the resin composition is increased and the occurrence of lumps is significantly suppressed when the resin composition is kneaded with an impact modifier. When the Mooney viscosity ML(1+4)125°C is 80 or lower, the graft copolymer can be easily melt-kneaded. The Mooney viscosity ML(1+4)125°C can be measured in accordance with JIS K6300-1:2013 using a test piece prepared by a cutting method in accordance with JIS K6298:2009.

[0016] The monomers constituting the side chains made of polymers of ethylenically unsaturated monomers contain at least styrene, i.e., the side chains may be made of a styrene polymer (styrene homopolymer) or a copolymer of styrene and another ethylenically unsaturated monomer (styrene copolymer).

[0017] Examples of other ethylenically unsaturated monomers include α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 4-methyl-1-hexene; internal olefins such as 2-butene, 2-pentene, 3-hexene, 4-heptene, 5-octene, and 2-methyl-2-pentene; vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile, and fumaronitrile; aromatic vinyl monomers such as α-methylstyrene, paramethylstyrene, and bromostyrene; acrylate monomers such as methyl acrylate, ethyl acrylate, and propyl acrylate; and methacrylate monomers such as methyl methacrylate, ethyl methacrylate, and propyl methacrylate. Vinyl cyanide monomers are preferred, and acrylonitrile is more preferred. The ethylenically unsaturated monomer may be used alone or in combination of two or more. The ethylenically unsaturated monomer may be one produced by a known method, or a commercially available one.

[0018] The ethylene-propylene-diene copolymer ratio of the graft copolymer, that is, the ratio of the amount of EPDM charged to the weight of the graft copolymer, is 40 to 60% by mass, and preferably 45 to 55% by mass.

[0019] The content of the graft copolymer based on the total mass of the graft copolymer and the styrene-based polymer may be 65 to 92.5 mass%, for example, 65 to 90 mass%, 65 to 80 mass%, 65 to 75 mass%, 70 to 92.5 mass%, 70 to 90 mass%, 70 to 80 mass%, or 70 to 75 mass%. When the content is 92.5 mass% or less, the torque required to knead the melt of the graft copolymer and the styrene-based polymer is suppressed.

[0020] The styrene polymer may be either a polymer of styrene alone (styrene homopolymer) or a copolymer of styrene and another monomer (styrene copolymer). When the styrene polymer is a styrene copolymer, the other monomer may be one type or two or more types. Examples of other monomers that can be used in combination with styrene include acrylonitrile and alkyl (meth)acrylate. The styrene polymer is preferably a copolymer of styrene and acrylonitrile. In this case, when the impact resistance modifier and the resin are kneaded to form a resin composition, the impact resistance of the resin composition is increased and the effect of suppressing the generation of lumps is remarkable.

[0021] The content of the styrene polymer based on the total mass of the graft copolymer and the styrene polymer can be, for example, 7.5 to 35 mass%, 7.5 to 30 mass%, 10 to 35 mass%, 10 to 30 mass%, 20 to 35 mass%, 20 to 30 mass%, 25 to 35 mass%, or 25 to 30 mass%. When the content is 7.5 mass% or more, the torque required to knead the melt of the graft copolymer and the styrene polymer can be reduced. When the content is 35 mass% or less, when the impact modifier and the resin are kneaded to form a resin composition, the impact resistance of the resin composition is increased and the generation of lumps can be significantly reduced.

[0022] The composition may further contain additives. Examples of additives include antioxidants and lubricants. Examples of lubricants include silicone oil, polyolefin wax, fatty acid metal salts, fatty acid amides, and fatty acid esters. Examples of polyolefin waxes include polyethylene wax, polypropylene wax, and olefin copolymer wax. Examples of fatty acid metal salts include calcium stearate, magnesium stearate, zinc stearate, aluminum stearate, and barium stearate. Examples of fatty acid amides include stearamide and ethylene bisstearamide. Examples of fatty acid esters include stearyl stearate, monoglyceride stearate, diglyceride stearate, and triglyceride stearate. The additive preferably includes an antioxidant. In this case, when the impact resistance modifier and the resin are kneaded to form a resin composition, the effect of increasing the impact resistance of the resin composition becomes significant.

[0023] Examples of antioxidants include primary antioxidants such as phenolic antioxidants and amine antioxidants, and secondary antioxidants such as phosphorus-based antioxidants and sulfur-based antioxidants. The antioxidant may include both a primary antioxidant and a secondary antioxidant, or may include only one of them. By using a primary antioxidant and a secondary antioxidant in combination, the effect of increasing the impact resistance of the resin composition obtained by using an impact modifier is preferably maintained. The primary antioxidant preferably includes a phenolic antioxidant, and the secondary antioxidant preferably includes a phosphorus-based antioxidant.

[0024] The antioxidant preferably contains a phenolic antioxidant and a phosphorus-based antioxidant. In this case, the effect of increasing the impact resistance of the resin composition obtained by using the impact resistance modifier is more preferably maintained. Examples of phenolic antioxidants include butylhydroxytoluene (BHT), 2-t-butylhydroquinone, butylated hydroxyanisole (BHA), and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Examples of phosphorus-based antioxidants include tris(2,4-di-tert-butylphenyl)phosphate, tris(nonylphenyl)phosphite (TNPP), triphenylphosphite (TPP), and 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.

[0025] The content of the antioxidant, based on the total mass of the graft copolymer and the styrene-based hard resin, can be, for example, 0.01 to 5.0 mass%, 0.01 to 2.0 mass%, 0.01 to 1.7 mass%, 0.01 to 1.4 mass%, 0.05 to 5.0 mass%, 0.05 to 2.0 mass%, 0.05 to 1.7 mass%, 0.05 to 1.4 mass%, 0.1 to 5.0 mass%, 0.1 to 2.0 mass%, 0.1 to 1.7 mass%, 0.1 to 1.4 mass%, 0.5 to 5.0 mass%, 0.5 to 2.0 mass%, 0.5 to 1.7 mass%, 0.5 to 1.4 mass%, 0.8 to 5.0 mass%, 0.8 to 2.0 mass%, 0.8 to 1.7 mass%, or 0.8 to 1.4 mass%. When the content is 0.01 to 5.0 mass%, the effect of increasing the impact resistance of the resin composition obtained by using the impact resistance modifier becomes more pronounced. When a phenolic antioxidant or a phosphorus-based antioxidant is contained as the antioxidant, the content of each of them can be 0.005 to 2.5 mass%, 0.005 to 1.0 mass%, 0.025 to 1.0 mass%, 0.05 to 1.0 mass%, 0.25 to 0.85 mass%, or 0.4 to 0.7 mass%, based on the total mass of the graft copolymer and the styrene-based hard resin.

[0026] Examples of resins that can be melt-kneaded with impact modifiers include rubber-reinforced polystyrene resins (HIPS resins), acrylonitrile-butadiene rubber-styrene polymers (ABS resins), acrylonitrile-acrylic rubber-styrene polymers (AAS resins), and methyl methacrylate-butadiene rubber-styrene resins (MBS resins); styrene polymers (PS resins), styrene-acrylonitrile copolymers (AS resins), α-methylstyrene-acrylonitrile copolymers (αMS-ACN resins), methyl methacrylate-styrene copolymers (MS resins), and methyl methacrylate-acrylonitrile-styrene copolymers. Examples of suitable resins include non-rubber-reinforced styrene-based resins such as copolymers of styrene and N-phenylmaleimide (MAS resin), copolymers of styrene and N-phenylmaleimide (S-NPMI resin), and copolymers of styrene and N-phenylmaleimide and acrylonitrile (SA-NPMI resin); polycarbonate resins (PC resin); polyester resins such as polyethylene terephthalate (PET resin), polybutylene terephthalate (PBT resin), and polylactic acid (PLA resin); polyacetal resins; polyamide resins such as nylon resin; acrylic resins such as polymethyl methacrylate (PMMA resin); polyvinyl chloride resins; and polyether resins such as polyphenylene ether resin. These resins can be produced by known methods.

[0027] The impact modifier can be produced using an extruder. FIG. 1 is a schematic diagram showing an example of the internal structure of an extruder. The extruder 100 shown in FIG. 1 includes a temperature-controllable cylinder 10 having a supply port 12 and a discharge port 16, and one or more rotatable screws 20 inserted into the cylinder 10. The screw 20 is connected to a drive unit that rotates the screw 20 via a shaft portion 20a. The cylinder 10 may be provided with one or more bend ports 14, and a hopper may be connected to the supply port 12.

[0028] Extruders are broadly classified into single-screw extruders with one screw, twin-screw extruders with two screws, and multi-screw extruders with three or more screws. When there are two or more screws, they may be of a co-rotating type in which all the screws rotate in the same direction, or of a counter-rotating type in which one screw rotates in the opposite direction to the other screw. From the viewpoint of the efficiency of producing the impact modifier, it is preferable that the number of screws is two.

[0029] The method for producing an impact modifier using the extruder 100 includes, for example, a step of supplying raw materials from the supply port 12 into the cylinder 10, a step of melting and kneading the raw materials in the cylinder 10 to obtain a molten material, a step of discharging the molten material from the discharge port 16, and a step of cooling the discharged molten material to obtain the impact modifier, which is a molten and kneaded material.

[0030] The raw material supplied from the supply port into the cylinder may contain the graft polymer and the styrene polymer in a ratio sufficient to obtain the impact modifier. In the cylinder 10, the raw material is heated by adjusting the temperature of the cylinder 10 to a predetermined temperature, and the raw material is kneaded by rotating the screw 20 inserted in the cylinder 10. The time required for melt kneading using the extruder (i.e., the time from when the material is supplied from the supply port to when it is discharged from the discharge port) can be adjusted by, for example, the length of the cylinder, the number of rotations of the screw, the number of screw pitches, and the number of screws.

[0031] The melt of the impact resistance modifier is discharged from the discharge port 16 of the extruder. The shape of the discharged melt is, for example, a thread (strand). From the viewpoint of producing the impact resistance modifier efficiently or with stable quality, the melt is preferably a strand. The cross-sectional shape of the discharge port 16 of the extruder can be, for example, a circle with a diameter of 1 to 50 mm.

[0032] When measuring the temperature of the molten material as it is discharged, if it is affected by the heat of the cylinder 10, the temperature cannot be measured stably. Therefore, the temperature of the molten material as it is discharged is determined as the temperature at a position far enough away from the discharge port 16 that the effect of the heat of the cylinder 10 is suppressed (for example, the temperature at a position 2 cm extruded from the discharge port end 16a). The temperature of the molten material at this time can be measured using a non-contact thermometer such as a radiation thermometer. The temperature of the molten material as it is discharged can be adjusted by kneading conditions such as the cylinder temperature, the time for melt-kneading, the screw rotation speed, the discharge rate, and the screw configuration.

[0033] The temperature of the molten material when extruded may be, for example, 310°C or lower, 305°C or lower, 302°C or lower, or 299°C or lower. When this temperature is 310°C or lower, when the impact resistance modifier and the resin are kneaded to form a resin composition, the impact resistance of the resin composition is increased and the effect of suppressing the generation of lumps is remarkable. This temperature may be higher than 240°C, or may be 250°C or higher, 260°C or higher, or 280°C or higher. When this temperature is higher than 240°C, the impact resistance of the resin composition obtained using the impact resistance modifier is increased and the effect of suppressing the generation of lumps is stably obtained. The temperature range may be greater than 240°C and less than or equal to 310°C, greater than 240°C and less than or equal to 305°C, greater than 240°C and less than or equal to 302°C, greater than 240°C and less than or equal to 299°C, greater than or equal to 250°C and less than or equal to 310°C, greater than or equal to 250°C and less than or equal to 305°C, greater than or equal to 250°C and less than or equal to 302°C, greater than or equal to 250°C and less than or equal to 299°C, greater than or equal to 260°C and less than or equal to 310°C, greater than or equal to 260°C and less than or equal to 305°C, greater than or equal to 260°C and less than or equal to 302°C, greater than or equal to 299°C, greater than or equal to 280°C and less than or equal to 310°C, greater than or equal to 280°C and less than or equal to 305°C, greater than or equal to 280°C and less than or equal to 302°C, or greater than or equal to 299°C.

[0034] The screw rotation speed can be, for example, 200 to 600 rpm. The rotation speed may be 300 rpm or more, 400 rpm or more, or 500 rpm or less, or 450 rpm or less. When the rotation speed is 200 rpm or more, the molten material can be easily kneaded sufficiently, and the impact resistance of the resin composition obtained using the impact resistance modifier is increased, and the effect of suppressing the generation of lumps is stably obtained. When the rotation speed is 600 rpm or less, when the impact resistance modifier and the resin are kneaded to form a resin composition, the impact resistance of the resin composition is increased, and the effect of suppressing the generation of lumps is significantly achieved. The rotation speed may be in the range of 200 to 500 rpm, 200 to 450 rpm, 300 to 600 rpm, 300 to 500 rpm, 300 to 450 rpm, 400 to 600 rpm, 400 to 500 rpm, or 400 to 450 rpm.

[0035] The diameters of the cylinder and the screw are not particularly limited as long as they can be used in combination with each other. For example, the cylinder diameter can be 10 mm to 200 mm, and the screw diameter can be 5 mm to 65 mm. The screw diameter may be 15 mm to 65 mm, 15 mm to less than 35 mm, or 35 mm to 65 mm. The length-to-diameter ratio (L / D) of the screw can be, for example, 35 to 60. When the ratio is 35 or more, the impact resistance of the resin composition obtained using the impact resistance modifier is increased, and the effect of suppressing the occurrence of lumps is stably achieved. When the ratio is 60 or less, when the impact resistance modifier and the resin are kneaded to form a resin composition, the impact resistance of the resin composition is increased, and the effect of suppressing the occurrence of lumps is significantly achieved.

[0036] The temperature of the cylinder 10 (hereinafter simply referred to as "cylinder temperature") may be set so that the temperature of the molten material when discharged from the extruder is within a predetermined range, and may be, for example, 120 to 300°C. The relationship between the cylinder temperature and the temperature of the molten material when discharged is determined appropriately according to the size of the extruder. For example, when the screw diameter D is 35 mm or more and 65 mm or less, the cylinder temperature may be 120 to 220°C, 140 to 200°C, or 160 to 180°C. Furthermore, when D is 15 mm or more and less than 35 mm, the cylinder temperature may be 220 to 300°C, 240 to 300°C, or 260 to 280°C. When the screw diameter D and the cylinder temperature satisfy the above relationship, when the impact resistance modifier and the resin are kneaded to form a resin composition, the impact resistance of the resin composition is increased and the generation of particles is significantly suppressed. The cylinder temperature may be the same from the supply port to the discharge port or may vary depending on the location, but it is preferable that the temperature be within the above temperature range.

[0037] The amount of the molten material discharged from the discharge port (hereinafter simply referred to as the "discharge rate") may be set so that the temperature of the molten material when discharged from the extruder is within a predetermined range, and may be, for example, 5 to 250 kg / hr. The discharge rate and the temperature of the molten material when discharged are appropriately determined according to the size of the extruder, etc. For example, when the screw diameter D is 35 mm or more and 65 mm or less, the discharge rate may be 50 to 400 kg / hr, 100 to 300 kg / hr, or 150 to 250 kg / hr. Furthermore, when D is 15 mm or more and less than 35 mm, the discharge rate may be 5 to 50 kg / hr, 10 to 40 kg / hr, or 15 to 25 kg / hr. When the screw diameter D and the discharge rate satisfy the above relationship, when the impact resistance modifier and the resin are kneaded to form a resin composition, the impact resistance of the resin composition is increased and the generation of particles is significantly suppressed.

[0038] The pressure applied to the melt in the extruder, i.e., in the cylinder, may be, for example, 3 MPa or more or 4 MPa or more. When the pressure is 3 MPa or more, the impact resistance of the resin composition obtained using the impact resistance modifier is increased, and the effect of suppressing the generation of lumps is stably obtained. The pressure may be, for example, 7 MPa or less or 6 MPa or less. When the pressure is 7 MPa or less, when the impact resistance modifier and the resin are kneaded to form a resin composition, the impact resistance of the resin composition is increased, and the effect of suppressing the generation of lumps is significantly achieved. The pressure range may be, for example, 3 to 7 MPa, 3 to 6 MPa, 4 to 7 MPa, or 4 to 6 MPa. The pressure is a value obtained, for example, by measuring the position of the tip of the screw in the cylinder using a resin pressure sensor.

[0039] According to the method for producing an impact resistance modifier, the impact resistance modifier is a melt-kneaded mixture of a composition including a graft copolymer in which side chains composed of a polymer of an ethylenically unsaturated monomer containing styrene are attached to a main chain composed of an ethylene-propylene-diene copolymer, and a styrene-based polymer, the graft copolymer having an ethylene-propylene-diene copolymer ratio of 40 to 60 mass%, and the content of the graft copolymer based on the total mass of the graft copolymer and the styrene-based polymer is 65 to 92.5 mass%, and the temperature of the molten impact resistance modifier when discharged from an extruder is 310°C or less. This method produces an impact resistance modifier that can improve the impact resistance of a resin composition when kneaded with a resin to form a resin composition and can suppress the occurrence of non-uniform portions in a molded product of the resin composition. [Example]

[0040] A 100 L pressure vessel was charged with 598 parts by mass of deionized water, 0.13 parts by mass of hydroxypropyl methylcellulose (trade name: Metrose 90SH-100, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.99 parts by mass of magnesium sulfate, and 100 parts by mass of ethylene-propylene-diene copolymer (a-1), and the atmosphere inside the vessel was replaced with nitrogen while stirring. Next, the tank was charged with a monomer mixture consisting of 78.2 parts by mass of styrene, 32.5 parts by mass of acrylonitrile, 1.70 parts by mass of tert-butyl peroxypivalate (B(PV)), 0.17 parts by mass of tert-butylperoxy-2-ethylhexanoate (trade name: Kayaester O, manufactured by Kayaku Nouryon Co., Ltd.), 0.07 parts by mass of 1,4-benzoquinone, and 0.40 parts by mass of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (trade name: SONGNOX1076, manufactured by SONGWON), and 50 parts by mass of deionized water, and the tank was pressurized to 0.1 kg / cm. 3 The pressure was increased to 1000kJ / min. The temperature inside the vessel was raised to 90°C, and the reaction was continued for 30 minutes after reaching 90°C. The temperature was raised to 120°C during the 30-minute reaction, and the reaction was continued at 120°C. After the reaction was completed, the temperature inside the vessel was cooled to 40°C, and the mixture was recovered, washed, and dried to obtain a graft copolymer (A). The ethylene-propylene-diene copolymer (a-1) used had propylene and diene ratios of 33% by mass and 8% by mass, respectively, of the total monomers constituting the ethylene-propylene-diene copolymer, the diene being 5-ethylidene-2-norbornene, and a Mooney viscosity (ML(1+4)125°C) of 69. The ethylene-propylene-diene copolymer (a-1) used was crushed from a bale state through a crusher to a size of 8 mm or less.

[0041] The ethylene-propylene-diene copolymer ratio of the graft copolymer (A) was 50.7%, which is the ratio of the charged weight of the ethylene-propylene-diene copolymer to the weight of the graft copolymer obtained in the above-mentioned step.

[0042] A styrene-based polymer (B-1) was obtained by bulk polymerization, in which the proportion of styrene in all monomers was 75% by mass and the proportion of acrylonitrile was 25% by mass. The styrene-based polymer (B-1) was dissolved in N,N-dimethylformamide to prepare a solution with a concentration of 0.4 g / 100 ml, and the reduced viscosity [IV] was calculated from the flow time measured at 30 ° C using a Cannon-Fenske viscometer. The reduced viscosity of the copolymer was found to be 0.6 dL / g.

[0043] A styrene polymer (B-2) was obtained by bulk polymerization, in which the proportion of styrene in all monomers was 75% by mass and the proportion of acrylonitrile was 25% by mass. The flow time of the styrene polymer (B-2) was measured by the above-mentioned method, and the reduced viscosity [IV] was calculated. As a result, the reduced viscosity of the styrene polymer (B-2) was 0.44 dL / g.

[0044] A styrene polymer (B-3) was obtained by emulsion polymerization, in which the proportion of styrene in all monomers was 75% by mass and the proportion of acrylonitrile was 25% by mass. The flow time of the styrene polymer (B-3) was measured by the above-mentioned method, and the reduced viscosity [IV] was calculated. As a result, the reduced viscosity of the styrene polymer (B-3) was 1.2 dL / g.

[0045] The impact modifiers according to Examples 1 to 3 and Comparative Examples 1 to 4 were prepared by the following procedure. Specifically, 0.4 parts by mass of a phenolic antioxidant, 0.4 parts by mass of a phosphorus-based antioxidant, and 0.2 parts by mass of silicone oil were mixed with the graft copolymer (A) and styrene-based polymer (B-1) blended in the proportions shown in Table 1. The resulting mixture was melt-kneaded using a co-rotating twin-screw extruder with a diameter of 26 mm and a screw length-to-diameter ratio (L / D) of 48 under the conditions of cylinder temperature, screw rotation speed, and output rate shown in Table 1, and the melt was extruded to obtain strands. The strands were cooled and then cut to obtain the impact modifiers according to Examples 1 to 3 and Comparative Examples 1 to 4. The strand according to Comparative Example 2 could not be extruded due to torque overload of the twin-screw extruder. Furthermore, under the extrusion conditions of Example 2, the pressure applied to the melt in the cylinder was 4 MPa.

[0046] The temperature of the molten material was also measured immediately after it was discharged from the twin-screw extruder. Specifically, a non-contact thermometer (THERMO-HUNTER PT-S80, manufactured by Optex FA Co., Ltd.) was used to measure the temperature of the strand at a position 2 cm away from the extruder head in the axial direction of the extruder. The results are shown in Table 1.

[0047] A mixture obtained by mixing 53 parts by mass of the impact modifier according to the Examples and Comparative Examples, 47 parts by mass of the styrene-based polymer (B-1), and 1 part by mass of ethylene bis(stearic acid amide) was melt-kneaded using a co-rotating twin-screw extruder having a diameter of 26 mm and an L / D ratio of 48 under conditions of a cylinder temperature of 230°C, a screw rotation speed of 400 rpm, and a discharge rate of 25 kg / hr, and the melt was extruded to obtain strands. The strands were cooled and then cut to obtain pellets for NC evaluation according to the Examples and Comparative Examples.

[0048] The mixture obtained by mixing 42 parts by mass of the impact modifier according to the Examples and Comparative Examples, 54 parts by mass of the styrene polymer (B-2), 4 parts by mass of the styrene polymer (B-3), and 1.5 parts by mass of ethylene bis(stearic acid amide) was melt-kneaded using a co-rotating twin-screw extruder having a diameter of 26 mm and an L / D of 48 under conditions of a cylinder temperature of 230 ° C, a screw rotation speed of 400 rpm, and a discharge rate of 40 kg / hr, and the melt was extruded to obtain a strand. The strand was cooled and then cut to obtain pellets for evaluation of the molded articles according to the Examples and Comparative Examples.

[0049] Using the NC evaluation pellets according to the examples and comparative examples, test pieces were molded in accordance with ISO 294, and impact resistance was measured. The impact resistance test was conducted in accordance with ISO 179, and the notched Charpy impact value (kJ / m 2 The results are shown in Table 1. In Table 1, "NC" means Charpy impact value.

[0050] Using the pellets for evaluation of molded particles according to the examples and comparative examples, films with a thickness of approximately 30 μm were produced, and the occurrence of particles during molding was evaluated. The films were produced using a press. Specifically, the pellets for evaluation of molded particles were sandwiched between the front side of the press plate and placed in a hand press at 220°C to melt the pellets. A pressure of 10 MPa was applied from above the press plate, and the molten resin extruded through the gaps between the press plates was stretched to produce a film. The presence or absence of particles (undispersed matter) in the resulting film was visually evaluated. The evaluation criteria were as follows: "Good" indicates that almost no undispersed matter of the graft copolymer was observed, and "Poor" indicates that a large amount of undispersed matter of the graft copolymer was observed. The results are shown in Table 1.

[0051] [Table 1] [Explanation of symbols]

[0052] 10...cylinder, 12...supply port, 14...bend port, 16...discharge port, 16a...discharge port end, 20...screw, 20a...shaft portion, 100...extruder.

Claims

1. A method for producing an impact modifier by extrusion, comprising: the impact resistance modifier is a melt-kneaded mixture of a composition including a graft copolymer in which a side chain made of a polymer of an ethylenically unsaturated monomer containing styrene is bonded to a main chain made of an ethylene-propylene-diene copolymer, and a styrene-based polymer; The graft copolymer has an ethylene-propylene-diene copolymer ratio of 40 to 60 mass %, the content of the graft copolymer is 65 to 92.5% by mass based on the total mass of the graft copolymer and the styrene-based polymer; The method of manufacturing, wherein the temperature of the melt of the impact modifier when discharged from the extruder is 310°C or less.

2. The manufacturing method according to claim 1, wherein the extruder comprises a temperature-controllable cylinder having a supply port and a discharge port, and one or more rotatable screws inserted in the cylinder.

3. The manufacturing method according to claim 2, wherein the temperature of the cylinder is 120 to 300°C.

4. The manufacturing method according to claim 2, wherein the temperature of the cylinder is 220 to 300°C when the screw diameter is 15 mm or more and less than 35 mm, and 120 to 220°C when the screw diameter is 35 mm or more and 65 mm or less.

5. The manufacturing method according to claim 2, wherein the rotation speed of the screw is 300 to 600 rpm.

6. The method according to claim 1, wherein the pressure applied to the melt in the extruder is 3 to 7 MPa.

7. The method according to any one of claims 1 to 6, wherein the composition contains an antioxidant.

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