Method for producing propylene-based resin composition

Abstract

SOLUTION: To provide a propylene-based resin composition which has an MFR (1) measured at 230°C and a load of 2.16 kg of 1-10 g / 10 min, a melt tension (1) of 23-35 mN, and 30 pieces or less of fish eyes with a diameter of 100-200 μm per 600 cm2.EFFECT: A propylene-based resin composition can suppress generation of a gel, and is excellent in physical properties such as film physical properties because of less generation of fish eyes.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a propylene-based resin composition and a method for producing the same, and more particularly to a method for producing a propylene-based resin composition and a method for producing a propylene-based resin composition. Rare occurrence The present invention relates to a propylene-based resin composition and a method for producing the same. [Background technology]

[0002] Polypropylene resins are used in a variety of applications, such as capacitor films used as storage batteries in hybrid vehicles, due to their excellent electrical properties, solvent resistance, moldability, and other characteristics, as well as their low specific gravity and low cost.

[0003] Various modifications have been attempted on polypropylene resins in order to further improve their physical properties. Polypropylene-based resins can produce gel during molding, resulting in a phenomenon known as fisheyes, which can degrade the properties of the polypropylene-based resin. For example, when polypropylene-based resins are used in capacitor films, the presence of fisheyes in the polypropylene-based resins can deteriorate the physical properties of the capacitor film. For this reason, there is a demand for the development of polypropylene-based resins that produce fewer fisheyes.

[0004] Patent Document 1 discloses a polypropylene resin having improved melt tension and processability, and a method for producing the same. Patent Document 2 discloses an inexpensive polypropylene resin composition having high melt tension and moderate fluidity, and a foamed sheet made from the resin that has excellent secondary processability, beautiful appearance, and excellent heat resistance. Patent Document 3 discloses a polypropylene resin composition having high melt tension and little gel, and a method for producing the same. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-171515 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-339365 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-150474 Summary of the Invention [Problem to be solved by the invention]

[0006] When modifying propylene-based resins using organic peroxides, both decomposition and crosslinking occur at relative rates. Therefore, conventional modification techniques for polypropylene-based resins cannot sufficiently suppress gel formation while maintaining high melt tension, making it difficult to further improve the physical properties of, for example, capacitor films.

[0007] An object of the present invention is to provide a propylene-based resin composition that maintains high melt tension while suppressing gel formation and reducing the occurrence of fisheyes, and a method for producing the same. [Means for solving the problem]

[0008] The present invention relates to, for example, the following [1] to [3]. [1] The MFR(1) measured at 230°C and a load of 2.16 kg is 1 to 10 g / 10 min, the melt tension(1) is 23 to 35 mN, and the fish eye diameter is 100 to 200 μm. 2 The propylene-based resin composition has 30 or less particles per unit area. [2] A method for producing a propylene-based resin composition according to [1], comprising melt-kneading 100 parts by mass of a propylene-based resin having an MFR(2) of 1 to 10 g / 10 min and a melt tension (2) of 15 to 30 mN, measured at 230°C under a load of 2.16 kg, and 0.001-2 parts by mass of an organic peroxide having a 1-minute half-life temperature of 100°C or less, at a resin temperature of 200 to 240°C using an extruder equipped with a screw in which the ratio of kneading element(s) to the L / D of the entire screw is 20% or more and 30% or less. [3] The method for producing a propylene-based resin composition according to [2], wherein MFR(1)>MFR(2) and melt tension(1)>melt tension(2). [Effects of the Invention]

[0009] The propylene-based resin composition of the present invention can suppress gel formation while maintaining high melt tension, and has little fisheye formation, so that it has excellent physical properties such as film properties. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a side view of screw configuration A. [Figure 2] FIG. 2 is a side view of screw configuration B. DETAILED DESCRIPTION OF THE INVENTION

[0011] The propylene-based resin composition of the present invention has an MFR(1) of 1 to 10 g / 10 min, a melt tension(1) of 23 to 35 mN, and a fish eye diameter of 100 to 200 μm of 600 cm, as measured at 230° C. under a load of 2.16 kg. 2 There are 30 or fewer per item.

[0012] The propylene-based resin composition of the present invention has an MFR (melt flow rate) (1) of 1 to 10 g / 10 min, preferably 2 to 8 g / 10 min, and more preferably 3 to 6 g / 10 min, measured at 230°C under a load of 2.16 kg in accordance with ASTM D 1238. If the MFR (1) is lower than 1 g / 10 min, gel is likely to form. If the MFR (1) is higher than 10 g / 10 min, film formability deteriorates.

[0013] The propylene-based resin composition of the present invention has a melt tension (1) of 23 to 35 mN, preferably 23 to 32 mN, and more preferably 25 to 30 mN. If the melt tension (1) is lower than 23 mN, film formability may deteriorate, and if it is higher than 35 mN, fisheyes may increase. The method for measuring the melt tension (1) will be explained in detail in the Examples.

[0014] The propylene-based resin composition of the present invention has a fisheye diameter of 100 to 200 μm and a length of 600 cm 2 The number of fish eyes is 30 or less per 600 cm, preferably 25 or less, and most preferably none. 2 When the number of fisheyes per unit area is 30 or less, the performance of the propylene-based resin composition is good. For example, when the polypropylene-based resin is used for a capacitor film, a capacitor film with good film properties is obtained. In addition, a beautiful appearance is obtained. Note that fisheyes with a diameter of more than 200 μm do not usually occur, and even if fisheyes with a diameter of less than 100 μm are present, they do not substantially cause any adverse effects.

[0015] The method for measuring the number of fisheyes will be explained in detail in the Examples. The propylene-based resin composition of the present invention can be produced, for example, by melt-kneading, at a resin temperature of 200 to 240°C, 100 parts by mass of a propylene-based resin having an MFR(2) of 1 to 10 g / 10 min and a melt tension (2) of 15 to 30 mN, measured at 230°C under a load of 2.16 kg, with 0.001 to 2 parts by mass of an organic peroxide having a 1-minute half-life temperature of 100°C or less.

[0016] The polypropylene-based resin is a propylene homopolymer or a copolymer of propylene and ethylene or an α-olefin having 4 to 20 carbon atoms. Examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene, with ethylene or an α-olefin having 4 to 10 carbon atoms being preferred. These α-olefins may form random copolymers or block copolymers with propylene. The polypropylene may contain structural units derived from these α-olefins in an amount of 5% by mass or less, preferably 2% by mass or less.

[0017] The polypropylene resin has an MFR(2) of 1 to 10 g / 10 min, preferably 2 to 8 g / 10 min, and more preferably 3 to 6 g / 10 min, measured at 230°C under a load of 2.16 kg in accordance with ASTM D 1238. If the MFR(2) is lower than 1 g / 10 min, gel is likely to form. If the MFR(2) is higher than 10 g / 10 min, film formability deteriorates.

[0018] The melt tension (2) of the polypropylene resin is 15 to 30 mN, preferably 18 to 25 mN. When the melt tension (2) is within the above range, the modification effect of the peroxide can be efficiently obtained. The method for measuring the melt tension (2) will be explained in detail in the Examples.

[0019] In the production method, if necessary, resins or rubbers other than the polypropylene-based resins may be used within the range that does not impair the effects of the present invention. Examples of such resins or rubbers include polyethylene; polyα-olefins such as polybutene-1, polyisobutene, polypentene-1, and polymethylpentene-1; ethylene or α-olefin / α-olefin copolymers such as ethylene / propylene copolymers, ethylene / butene-1 copolymers, and propylene / butene-1 copolymers having a propylene content of less than 75% by mass; ethylene or α-olefin / α-olefin / diene monomer copolymers such as ethylene / propylene / 5-ethylidene-2-norbornene copolymers having a propylene content of less than 75% by mass; ethylene / vinyl chloride copolymers, ethylene / vinylidene chloride copolymers, ethylene / acrylonitrile copolymers, ethylene / methacrylonitrile copolymers, and ethylene / vinyl acetate copolymers. Ethylene or α-olefin / vinyl monomer copolymers such as copolymers, ethylene / acrylamide copolymers, ethylene / methacrylamide copolymers, ethylene / acrylic acid copolymers, ethylene / methacrylic acid copolymers, ethylene / maleic acid copolymers, ethylene / ethyl acrylate copolymers, ethylene / butyl acrylate copolymers, ethylene / methyl methacrylate copolymers, ethylene / maleic anhydride copolymers, ethylene / metal acrylate copolymers, ethylene / metal methacrylate copolymers, ethylene / styrene copolymers, ethylene / methylstyrene copolymers, and ethylene / divinylbenzene copolymers; polydiene copolymers such as polyisobutene, polybutadiene, and polyisoprene; vinyl monomer / diene monomer random copolymers such as styrene / butadiene random copolymers; Vinyl monomer / diene monomer / vinyl monomer block copolymers such as styrene / butadiene / styrene block copolymers; hydrogenated (vinyl monomer / diene monomer random copolymers) such as hydrogenated (styrene / butadiene random copolymers); hydrogenated (vinyl monomer / diene monomer / vinyl monomer block copolymers) such as hydrogenated (styrene / butadiene / styrene block copolymers);Examples include vinyl monomer / diene monomer / vinyl monomer graft copolymers such as acrylonitrile / butadiene / styrene copolymer and methyl methacrylate / butadiene / styrene copolymer; vinyl polymers such as polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl acetate, polyethyl acrylate, polybutyl acrylate, and polymethyl methacrylate; and vinyl copolymers such as vinyl chloride / acrylonitrile copolymer, vinyl chloride / vinyl acetate copolymer, acrylonitrile / styrene copolymer, and methyl methacrylate / styrene copolymer.

[0020] The amount of these resins or rubbers added to the polypropylene-based resin varies depending on the type of resin or rubber, and is not limited as long as it does not impair the effects of the present invention as described above, but it is usually preferable that it be about 25 mass% or less.

[0021] Furthermore, in addition to the polypropylene-based resin, additives such as stabilizers such as antioxidants, ultraviolet absorbers, metal soaps and hydrochloric acid absorbers, nucleating agents, lubricants, plasticizers, fillers, reinforcing agents, pigments, dyes, flame retardants and antistatic agents may be used as needed within the range that does not impair the effects of the present invention.

[0022] For the purpose of increasing the melt tension, it is possible to add a vinyl monomer to the polypropylene resin as long as the effect of the present invention is not impaired, but it is preferable that the amount is about 5 to 25% by mass.

[0023] Examples of the vinyl monomer referred to in the present invention include vinyl chloride, vinylidene chloride, styrene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl acetate, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, metal acrylates, metal methacrylates, acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, and glycyl acrylate; and methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, and glycyl methacrylate.

[0024] The organic peroxide used in the production method has a one-minute half-life temperature of 100°C or less. If the one-minute half-life temperature is higher than 100°C, decomposition of the resin is accelerated, which is undesirable. Furthermore, it is preferable that these organic peroxides have the ability to abstract protons from the polypropylene resin after decomposing to generate radicals.

[0025] The organic peroxide is preferably a peroxydicarbonate. The peroxycarbonate in the present invention is a compound represented by the general formula R 1 -OC(O)OOC(O)OR 2 where R 1 and R 2 is CH3, 2-i-C3H7O-C6H4, C2H5CH(CH3), 4-CH3-C6H4, Cl3CC(CH3)2, C7H 15 , c-CH 11 CH2, 3-t-C4H9-C6H5, Cl3Si(CH2)3, C6H5, CH3CH(OCH3)CH2CH2, C6H5OCH2H2, C6H5CH2, Z-C8H 17 CH=CH(CH2)8, 2-CH3-C6H4, (CH3)2CHCH2CH(CH3), 3,4-di-CH3-C6H3, Cl3C, CHCH(Cl), ClCH2, [C2H5OC(O)] 2CH(CH3), 3,5-di-CH3-C6H3, C8H 17 , C2H5, C 18 H37 , 2-oxo-1,3-dioxane-4-CH2, C2H5CH(Cl)CH2, 4-CH3O-C6H4, i-C4H9, CH3SO2CH2CH2, C 12 H 25 , C6H5CH(Cl)CH2, H2C=CHCH2, 2-Clc-C6H 10 , H2C=C(CH3)CH2, c-CH6H 11 , ClCH2CH2, 4-[C6H5-N=N]-C6H4CH2, stearyl, 1-naphthyl, 4-t-C4H9-C6H 10 , 2,4,5-tri-Cl-C6H2, Cl(CH2)2, C 14 H 29 , 9-Florenyl, 4-NO2-C6H4CH2, 2-i-C3H7-C6H4, CH3OCH2CH2, H2C=C(CH3), 3-CH3-C6H4, BrCH2CH2, 3- CH3-5-i-C3H7-C6H3, Br3CCH2, C2H5OCH2CH2, HC2=CH, i-C3H7, 2-C2H5CH(CH3)-c6H4, Cl3CCH2, C5H 11 , cC 12 H 23 , 4-t-C4H9-C6H4, C6H 13 , C3H7, CH3OCH2CH2, C6H 13 CH(CH3), CH3OC(CH3)2CH2CH2, C3H7OCH2CH2, CH3OCH2CH(CH3), 2-i-C3H7-5-CH3-c-C6H9, C4H9OCH2CH2, t-C4H9, (CH3)3CCH2, etc. Here, i means iso, t means tertiary, z means cis, and c means cyclic.

[0026] Among these compounds, preferred compounds include dicetyl peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate, dimyristyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-n-butyl peroxydicarbonate, and bis(2-ethylhexyl) peroxydicarbonate.

[0027] In the above-described production method, the amount of organic peroxide used is 0.001 to 2 parts by mass, preferably 0.01 to 1 part by mass, and more preferably 0.1 to 0.8 parts by mass, per 100 parts by mass of the propylene-based resin. When the amount of organic peroxide used is within this range, the propylene-based resin can be suitably modified, resulting in a propylene-based resin composition with fewer fisheyes. If the amount is less than this range, the modification effect tends to be insufficient. On the other hand, if the amount is greater than this range, gel components may be generated, reducing foaming properties, or the decomposition products of the organic peroxide may reduce the food hygiene of the modified propylene-based resin or produce an unpleasant odor.

[0028] In the above-mentioned production method, the propylene-based resin and organic peroxide are melt-kneaded at a resin temperature of 180 to 300°C, preferably 200 to 240°C. The optimum resin temperature during melt-kneading is about 220°C. A melt-kneading temperature within this range is preferable because the propylene-based resin is sufficiently melted and the organic peroxide is completely decomposed, preventing further changes in the properties of the resulting composition during molding. The melt-kneading time is generally 10 seconds to 5 minutes, preferably 30 to 60 seconds.

[0029] Apparatuses that can be used for melt-kneading include kneaders such as co-kneaders, Banbury mixers, Brabenders, single-screw extruders, twin-screw extruders, horizontal drum mixers such as twin-screw surface regenerators and twin-screw multi-disk devices, and vertical mixers such as double helical ribbon mixers. Of these, extruders are particularly preferred because they enable sufficient kneading and are highly productive.

[0030] The screw provided in the extruder is configured by combining a large number of forward kneading pieces, reverse kneading pieces, forward flight pieces, reverse flight pieces, and the like. The melt-kneading is preferably carried out using an extruder equipped with a screw in which the proportion of kneading element elements, such as forward kneading pieces and reverse kneading pieces, relative to the overall L / D of the screw is 20% or more and 30% or less, more preferably 20% or more and 25% or less. Melt-kneading using an extruder equipped with such a screw can increase the melt tension while obtaining a propylene-based resin composition with few fish eyes and gels. If the proportion exceeds 30%, excessive heat is generated, making it difficult to obtain the desired melt tension.

[0031] Figures 1 and 2 show side views of specific examples of screws provided in extruders. In screw configuration A shown in Figure 1, the ratio of the kneading element to the overall L / D of the screw is 22%. In screw configuration B shown in Figure 2, the ratio of the kneading element to the overall L / D of the screw is 16%.

[0032] The production method is preferably carried out under conditions where MFR(1)>MFR(2) and melt tension(1)>melt tension(2), since this achieves both moldability and fisheye reduction. These conditions can be achieved by adjusting the resin temperature during kneading.

[0033] By the above-mentioned operation, the propylene-based resin, the organic peroxide, and other additive materials added as required are melt-kneaded to obtain a propylene-based resin composition.

[0034] When modifying a propylene-based resin using an organic peroxide, both decomposition and crosslinking occur at relative rates. As the crosslinking rate increases, the melt tension is expected to improve, but the rate of gel formation increases. It is believed that the production method described above controls the rates of decomposition and crosslinking by limiting the kneading conditions to specific conditions, thereby producing a propylene resin composition with increased melt tension and less gel formation.

[0035] The propylene resin composition of the present invention produces little gel and has few fish eyes, and therefore can be used in a variety of applications, and can be particularly suitably used for capacitor films. [Example]

[0036] In the following examples and comparative examples, the physical properties were measured or evaluated by the following methods.

[0037] [MFR] The MFR was measured at 230°C under a load of 2.16 kg in accordance with ASTM D1238.

[0038] [Melt tension] Using a melt tension measuring device (manufactured by Toyo Seiki Seisakusho, Ltd.), the winding load of a pulley equipped with a load cell detector was measured under the conditions of an orifice (length L 8.00 mm, diameter D 2.095 mm), a set temperature of 200°C, a piston descending speed of 15 mm / min, and a winding speed of 15 mm / min, and this measured value was taken as the melt tension.

[0039] [Fisheye] A 30 μm cast film was produced from the propylene resin composition using a 20 mmφ cast molding machine, and the film was cut into 600 cm 2 The number of fish eyes with a diameter of 100 to 200 μm per unit area was counted by microscopic observation.

[0040] [Example 1] 100 parts by mass of propylene homopolymer (Prime Polymer F133PT, MFR: 5 g / 10 min, melt tension: 20 mN) was melt-extruded at 220°C and 500 rpm using a co-rotating, fully intermeshing twin-screw extruder (JSW TEX44, screw diameter: 47 mm, L / D: 53.5) with screw configuration A shown in Figure 1. This melt-extrusion process yielded propylene-based resin pellets. In screw configuration A, the proportion of the elements for the kneading section in the L / D of the entire screw was 22%.

[0041] The pellets were used to measure the MFR and melt tension by the above-mentioned methods. 。 Conclusion The results are shown in Table 1.

[0042] [Comparative Example 1] Pellets and sheets of propylene-based resin pellets were produced in the same manner as in Example 1, except that no organic peroxide (radical polymerization initiator) was added. Measurements of MFR, melt tension, and fisheye were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0043] Comparative Example 2 Pellets and sheets of propylene-based resin pellets were produced in the same manner as in Example 1, except that the resin temperature during melt-kneading was 270° C. Melt tension and fisheye measurements were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0044] Comparative Example 3 Pellets and sheets of propylene-based resin pellets were produced in the same manner as in Example 1, except that screw configuration B shown in FIG. 2 was used instead of screw configuration A. In screw configuration B, the proportion of the kneading element in the L / D of the entire screw was 16%. Measurements of MFR, melt tension, and fisheye were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0045] [Table 1]

[0046] In the case of Example 1, the number of fisheyes formed was about the same as in Comparative Example 1, in which no peroxide was added, and the melt tension was increased. In other words, even when modification was performed with peroxide, the formation of fisheyes was suppressed.

[0047] On the other hand, in Comparative Example 2 where the kneading temperature was 270°C, the number of fish eyes increased, which deteriorated the appearance of the film and resulted in defects in the film product. Also, comparison In Example 3, the influence of the screw during kneading increased the formation of fish eyes, which, like Comparative Example 2, deteriorated the appearance of the film, resulting in product defects.

Claims

1. 100 parts by mass of a propylene-based resin having an MFR (2) of 1 to 10 g / 10 min and a melt tension (2) of 15 to 30 mN, measured at 230°C under a load of 2.16 kg, and 0.001 to 2 parts by mass of an organic peroxide having a 1-minute half-life temperature of 100°C or less, are melt-kneaded at a resin temperature of 200 to 240°C, A propylene-based resin composition having an MFR (1) of 1 to 10 g / 10 min and a melt tension (1) of 23 to 32 mN, measured at 230°C and a load of 2.16 kg, is produced. A method for producing a propylene-based resin composition.

2. 2. The method for producing a propylene-based resin composition according to claim 1, wherein the melt-kneading is carried out using an extruder equipped with a screw in which the ratio of the kneading element to the L / D of the entire screw is 20% or more and 30% or less.

3. 3. The method for producing a propylene-based resin composition according to claim 1, wherein MFR(1)>MFR(2) and melt tension(1)>melt tension(2) are satisfied.

4. The method for producing a propylene-based resin composition according to any one of claims 1 to 3, wherein the propylene-based resin is a propylene homopolymer.

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