JP2005060603A - Polypropylene resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems of the flammability and the lowering of rigidity which is a principal property of polypropylene resins and provide a phosphate-based flame-retardant polypropylene resin composition having excellent non-dripping property in burning, appearance, etc., and exhibiting excellent flame-retardance by the use of a small amount of flame retardant by compounding PTFE and a phosphate-based flame-retardant to the resin. <P>SOLUTION: The flame-retardant polypropylene resin composition is produced by the melt kneading of (A) a crystalline polypropylene resin having an MFR of 0.1-80 g/10 min and an isotactic pentad fraction of ≥0.97 and (B) a phosphate-based flame-retardant with (C) a master batch containing melt-kneaded tetrafluoroethylene resin (PTFE). The amount of the master batch C is 0.01-3 pts. wt. in terms of PTFE based on 100 pts. wt. of A+B. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polypropylene resin composition. More specifically, the present invention relates to a flame retardant polypropylene resin composition obtained by blending a specific amount of a tetrafluoroethylene resin masterbatch that is easy to handle without aggregating with an external force into a polypropylene resin together with a phosphate flame retardant.

  It is known that tetrafluoroethylene resin (PTFE) has a great effect of preventing dripping in the flame retardancy of a thermoplastic resin when added in a small amount to the thermoplastic resin.

  In general, when PTFE is added to a thermoplastic resin, the melting point of PTFE is higher than the processing temperature of the thermoplastic resin, so that the PTFE is kneaded below the melting point of PTFE. PTFE is easily fibrillated or aggregated by receiving a shearing force, and PTFE kneaded and added to a thermoplastic resin is said to be fiberized into a network and exhibit effects such as dripping prevention. However, the ease of fiberization and aggregation of PTFE is very troublesome in handling, and various techniques for improving the handling properties have been proposed. For example, a method of treating PTFE with a higher fatty acid dispersant in advance has been proposed (see Patent Document 1).

  On the other hand, various granular compositions containing PTFE at a high concentration have been studied in order to improve the handleability (see Patent Documents 2 to 5). However, the polyolefin resin has problems such as insufficient dispersibility of PTFE even in these technologies, flame retardancy, prevention of dripping during combustion, and insufficient rigidity.

Moreover, in order to improve the flame retardance of polyolefin, the method of using combining a specific phosphate flame retardant and an anti-drip agent is proposed (cited reference 6). However, even with these methods, a composition having both sufficient flame retardancy and rigidity has not been achieved.
Japanese Patent Laid-Open No. 10-30046 JP 09-324124 A JP 09-324071 A JP 09-324092 A JP 2001-2947 A JP-A-2003-26935

  The object of the present invention is to solve the problem of rigidity reduction, which is a flame retardant property and basic physical properties of polypropylene resin in view of the above problems, and by combining PTFE and a phosphate flame retardant, An object of the present invention is to provide a phosphate-based flame-retardant polypropylene resin composition that has excellent anti-dripping properties, appearance, and the like, and has excellent flame retardancy with a small amount of flame retardant.

  As a result of intensive investigations to obtain a phosphorus-based flame-retardant polyolefin resin composition excellent in flame retardancy, anti-dripping property, rigidity, appearance, etc., the present inventors obtained PTFE by melt-kneading with a matrix resin. It was found that the object was achieved by melt-kneading the granular PTFE master batch obtained with a specific polypropylene resin and a phosphate flame retardant, and the present invention was completed.

  That is, the present invention provides a total amount of 100 of the crystalline polypropylene resin (A) and the phosphate flame retardant (B) having an MFR of 0.1 to 80 g / 10 min and an isotactic pentad fraction of 0.97 or more. A master batch (C) obtained by melting and kneading tetrafluoroethylene resin (PTFE) with respect to parts by weight is present in a flame-retardant polypropylene resin composition obtained by melting and kneading 0.01 to 3 parts by weight as PTFE.

  According to the present invention, a polypropylene resin composition having excellent flame resistance in addition to excellent mechanical strength and moldability can be obtained. Since a small amount of PTFE masterbatch is used as a flame retardant and no chlorine and bromine-containing compounds are used, the environmental impact is small.

  Hereinafter, the present invention will be described in detail.

Polypropylene resin (A)
Examples of the polypropylene resin (A) used in the present invention include a crystalline propylene homopolymer, a random copolymer of propylene as a main component and the propylene and ethylene or an α-olefin having 4 or more carbon atoms, crystalline polypropylene and propylene. Examples include so-called block copolymers made of a rubbery copolymer of ethylene, or a mixture of two or more thereof.

  The melt flow rate (MFR) of the polypropylene resin (A) of the present invention is 0.1 to 80 g / 10 minutes, preferably 5 to 60 g / 10 minutes, and the isotactic pentad fraction is 0.97 or more, Preferably, it has a polypropylene crystalline polypropylene portion having a high degree of stereoregularity of 0.98 or more.

The isotactic pentad fraction ([mmmm]) in the present invention is an isotactic fraction of pentad units in a polypropylene molecular chain measured by a method using ¹³ C-NMR (Macromolecules, 6, page 925 (1973)). In other words, the isotactic pentad fraction is a fraction of a propylene monomer unit at the center of a chain in which five propylene monomer units are continuously meso-bonded. However, peak assignment was performed based on the method described in Macromolecules, Vol. 8, page 687 (1975). The chemical shift in the total absorption peak in the methyl carbon region of a specific ¹³ C-NMR spectrum is as follows. The methyl group of the third unit of the 5-unit propylene unit having a head-to-tail bond and the same methyl branching direction is represented by 21. It is set as 8 ppm, and the chemical shift of the other carbon peak is based on this, and the isotactic pentad unit is measured as the intensity fraction of the [mmmm] peak.

Specifically, it is a value measured according to the following ¹³ C-NMR spectrum measurement method. ^{The 13} C-NMR spectrum was obtained by dissolving about 100 mg of a polypropylene sample in a mixed solvent of 2 ml of orthodichlorobenzene and 0.2 ml of benzene-d6 in a sample tube for 10 mmφ NMR, and a 500 MHz NMR apparatus (manufactured by Varian, ¹³ C-NMR was measured at a resonance frequency of 125.7 MHz using Inova 500).

  [Mmmm] is 0.97 or more, preferably 0.98 or more. If it is less than 0.97, when various flame retardants are blended, rigidity is lowered and sufficient mechanical properties cannot be maintained.

  The production method of the polypropylene resin (A) of the present invention is not particularly limited as long as the above MFR and [mmmm] are satisfied. Usually, a Ziegler type highly active catalyst or a metallocene catalyst is used. Manufactured.

  The Ziegler (ZN) catalyst is preferably a highly active catalyst in which a solid catalyst component containing magnesium, titanium, halogen, and an electron donor as essential components and an organoaluminum compound are combined.

  Examples of metallocene catalysts include organic compounds having a cyclopentadienyl skeleton and transition metal such as zirconium, hafnium, and titanium, metallocene complexes coordinated with halogen atoms, alumoxane compounds, ion-exchange silicates, organoaluminum compounds, and the like. The combined catalyst is effective.

  Examples of comonomers to be copolymerized with propylene include ethylene, butene-1, pentene-1, hexene-1, 4-methyl-pentene-1. These comonomer components are 0 to 15% by weight, preferably 0 to 10% by weight. Among these, a particularly preferable one is a random copolymer of propylene and ethylene and / or butene-1.

  The amount ratio of each monomer in the reaction system does not need to be constant over time, it is convenient to supply each monomer at a constant mixing ratio, and the mixing ratio of the supplied monomers can be changed over time. Is also possible. Also, any of the monomers can be added in portions in consideration of the copolymerization reaction ratio.

  As the polymerization method, any method can be adopted as long as the catalyst component and each monomer come into efficient contact. Specifically, a slurry method using an inert solvent, a bulk method using substantially no inert solvent as a solvent, a solution method, or a solution method or substantially using no liquid solvent, each monomer being substantially gaseous. A gas phase method can be employed.

  Further, either continuous polymerization or batch polymerization may be used. In the case of slurry polymerization, a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, pentane, cyclohexane, benzene and toluene can be used alone or as a polymerization solvent.

As the polymerization conditions, the polymerization temperature is -78 to 160 ° C, preferably 0 to 150 ° C, and hydrogen can be supplementarily used as the molecular weight regulator at that time. The polymerization pressure is 0 to 90 kg / cm ² · G, preferably 0 to 60 kg / cm ² · G, particularly preferably 1 to 50 kg / cm ² · G.

Phosphate flame retardant (B)
Any phosphate-based flame retardant (B) used in the present invention can be used as long as it is generally used as a flame retardant for polyolefins. For example, ammonium polyphosphate, melamine polyphosphate, piperazine polyphosphate, piperazine orthophosphate, melamine pyrophosphate, piperazine pyrophosphate, melamine polyphosphate, melamine orthophosphate, calcium phosphate, magnesium phosphate, etc. An acid salt compound or a mixture is mentioned.

  In the above examples, instead of melamine and piperazine, N, N, N ′, N′-tetramethyldiaminomethane, ethylenedidiamine, N, N′-dimethylethylenediamine, N, N′-diethylethylenediamine, N, N— Dimethylethylenediamine, N, N-diethylethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-diethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine , Tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, trans-2,5-dimethylpiperazine, 1 , 4-Bis (2-aminoethyl) piperazine, 1,4-bis 3-aminopropyl) piperazine, acetoguanamine, benzoguanamine, acrylic guanamine, 2,4-diamino-6-nonyl-1,3,5-triazine, 2,4-diamino-6-hydroxy-1,3,5-triazine 2-amino-4,6-dihydroxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-ethoxy-1, 3,5-triazine, 2,4-diamino-6-propoxy-1,3,5-triazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6 -Mercapto-1,3,5-triazine, 2-amino-4,6-dimercapto-1,3,5-triazine, ammelin, benzguanamine, acetoguanamine, phthalodi Guanamine, melamine cyanurate, melamine pyrophosphate, butylene diguanamine, norbornene diguanamine, methylene diguanamine, ethylene dimelamine, trimethylene dimelamine, tetramethylene dimelamine, hexamethylene dimelamine, 1,3-hexylene dimeramine A compound in which etc. are replaced can be used similarly. As a commercial item, Asahi Denka Co., Ltd., ADK STAB FP2000, ammonium polyphosphate, etc. are mentioned.

  The compounding quantity of the phosphate compound used by this invention is 10-50 weight part with respect to 100 weight part of polyolefin resin, Preferably it is 15-40 weight part, More preferably, it is 22-30 weight part. If the blending amount is less than 10 parts by weight, a sufficient flame retardant effect cannot be obtained, and if it exceeds 50 parts by weight, the properties of the polyolefin resin are deteriorated, and this is disadvantageous in terms of economic efficiency. .

Master batch (C) in which tetrafluoroethylene resin (PTFE) is melt-kneaded
The PTFE used in the present invention is a tetrafluoroethylene homopolymer or a copolymer containing tetrafluoroethylene as a main component. Comonomers copolymerized with tetrafluoroethylene include fluorine-containing olefins such as difluoroethylene, trifluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, fluoroalkylethylene, perfluoroalkyl vinyl ether, and perfluoroalkyl (meth) acrylate. The fluorine-containing alkyl (meth) acrylate can be used. The content of the copolymer component is preferably 10% by weight or less with respect to tetrafluoroethylene.

  Commercial raw materials for aqueous dispersions of polytetrafluoroethylene particles include Asahi Glass Fluoropolymer Fluon AD-1, AD-936, Daikin Industries, Polyflon D-1, D-2, Mitsui DuPont Fluorochemicals Teflon 30J (Teflon is a registered trademark) can be given as a representative example.

  An aqueous dispersion of PTFE particles can be obtained by polymerizing a tetrafluoroethylene monomer and, if necessary, an appropriate comonomer by an emulsion polymerization method using a fluorine-containing surfactant. The particle size of the aqueous dispersion of PTFE particles is preferably 0.05 to 1.0 μm.

  The aqueous dispersion of PTFE particles can be poured into hot water in which a metal salt such as calcium chloride or magnesium sulfate is dissolved and dried after being salted out and solidified, or powdered by spray drying. A PTFE masterbatch can be prepared by blending the obtained powder into a matrix resin such as polypropylene together with molding aids such as an antioxidant, a stabilizer and a lubricant, and melt-kneading them.

  In some cases, PTFE can be modified by polymerizing a polymerizable vinyl compound in an aqueous dispersion of PTFE particles. The PTFE-modified product obtained at this time forms a uniform mixture of PTFE and a polymer of a vinyl compound, and is effective in improving the mixing property with polypropylene.

  Examples of the polymerizable vinyl compound include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, t-butylstyrene, o-ethylstyrene, p-chlorostyrene, o-chlorostyrene, 2,4-dichloro. Aromatic vinyl monomers such as styrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth ) (Meth) acrylic acid ester monomers such as 2-ethylhexyl acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate; acrylonitrile, meta Vinyl cyanide monomers such as acrylonitrile; α, β- such as maleic anhydride Saturated carboxylic acid; maleimide monomer such as N-phenylmaleimide, N-methylmaleimide, N-cyclohexylmaleimide; epoxy group-containing monomer such as glycidyl methacrylate; vinyl ether monomer such as vinylmethylether and vinylethylether; Examples thereof include vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate; α-olefin monomers such as ethylene, propylene and isobutylene; and diene monomers such as butadiene, isoprene and dimethylbutadiene. Of these, a (meth) acryl monomer having a polar group is preferred. These monomers can be used alone or in admixture of two or more. The PTFE content in the modified PTFE is usually selected from the range of 1 to 90% by weight.

  Examples of commercially available PTFE modified with an acrylic monomer include a modifier for thermoplastic resin (Methbrene A-3000) manufactured by Mitsubishi Rayon Co., Ltd.

  The polypropylene resin composition of the present invention has a PTFE master batch (C) of 0.01 to PTFE based on 100 parts by weight of the total amount of the crystalline polypropylene resin (A) and the phosphate flame retardant (B). It is important to blend 3 parts by weight, preferably 0.02 to 1.0 parts by weight, more preferably 0.05 to 0.5 parts by weight. If it is 0.01 parts by weight or less, there is no effect of preventing dripping at the time of combustion, and if it is 3 parts by weight or more, it not only deteriorates mechanical properties and deteriorates the appearance, but is also economically disadvantageous.

  Since PTFE is fibrillated by a shearing force and adopts a fibrous network structure during melt kneading with the crystalline polypropylene resin (A), it has an effect of improving the melt tension of the molten resin. In order to efficiently generate and disperse this fibril, a product obtained by modifying PTFE with a special acrylic resin is preferable.

  In the present invention, PTFE is used in the form of a masterbatch that is melt-kneaded with a matrix resin. When not used as a masterbatch and used as a powdery material of PTFE alone, it is not uniformly dispersed throughout the molded body when combined with the polypropylene resin, so that the dripping prevention effect is not exhibited effectively. The master batch is mixed with an appropriate amount of modified or unmodified PTFE powder in a matrix component such as polypropylene resin, mixed with a tumbler mixer or Henschel mixer, and then using a twin screw extruder or the like. Manufactured by pelletizing under suitable melting conditions. If necessary, various additives such as an antioxidant, a lubricant, and a light stabilizer can be blended at the same time.

  The phosphate flame retardant (B) may be previously mixed with the crystalline polypropylene resin (A) and then mixed with the PTFE master batch (C). (A), (B), (C) may be mixed simultaneously, and various additives may be mixed simultaneously.

Metal oxide (D)
Examples of the metal oxide (D) used in the present invention include zinc oxide, iron oxide, aluminum oxide, and molybdenum oxide. More preferable metal oxides are zinc oxide and iron oxide, and those having an average particle size of 30 μm or less, preferably 10 μm or less, and more preferably 1 μm or less are suitable. When the average particle diameter of the metal oxide is larger than 30 μm, dispersibility with respect to the polyolefin resin is deteriorated, and high flame retardance cannot be obtained.

  The compounding amount when using the metal oxide used in the present invention is preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the total amount of the polypropylene resin (A) and the phosphate flame retardant (B). More preferably, it is 0.1 to 3 parts by weight. If it is less than 0.05 part by weight, a synergistic flame retardant effect due to sufficient addition cannot be obtained, and if it exceeds 5 parts by weight, it is disadvantageous for economic efficiency.

Optional component (E)
In the polypropylene resin composition of the present invention, any additive can be blended in order to further impart other characteristics within a range not impairing the effects of the present invention. For example, antioxidants, processing stabilizers, ultraviolet absorbers, light stabilizers, antistatic agents, crystallization nucleating agents, lubricants, metal deactivators, color pigments, various inorganic fillers, glass fibers, etc. may be added. I can do it. Also, high density polyethylene (HDPE), high pressure method low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene propylene rubber (EPR), ethylene butene rubber (EBR), C2 / C6 copolymer, C2 / C8 copolymer, polystyrene, ethylene / acrylic acid copolymer, ethylene / vinyl acetate copolymer (EVA), styrene / butadiene copolymer hydrogenated product (SEBS), etc. can be combined. is there. It is also possible to combine a modified polyolefin containing a polar group such as a maleic anhydride-modified product of polypropylene and a maleic anhydride-modified product of ethylene / propylene copolymer.

  Among the above optional components, various stabilizers and the like are usually in the range of 0 to 5 parts by weight with respect to 100 parts by weight of the crystalline polypropylene resin (A), and the inorganic filler and polymer compounding agent are in the range of 0 to 30 parts by weight. Used in.

Method for Producing Phosphate Flame Retardant Polypropylene Resin Composition The method for producing the phosphate flame retardant polypropylene resin composition of the present invention is not particularly limited. A predetermined amount of tetrafluoroethylene masterbatch (C) is mixed with 100 parts by weight of the total amount of the crystalline polypropylene resin (A) and the phosphate flame retardant (B), and if necessary, other additives Mix a predetermined amount. For example, each component is put into a mixing apparatus such as a super mixer and a tumbler mixer, mixed for 1 to 5 minutes, and then the obtained mixture is melt-kneaded at a kneading temperature of 170 to 230 ° C. with an extruder, a heating roll, a kneader, etc. Can be mentioned. Among them, the extruder kneading with two axes is preferable in terms of productivity and flame retardancy.
<Operation of the invention>
The polypropylene resin composition of the present invention exhibits flame retardancy and drip resistance superior to conventionally known flame retardant polyolefin resins, and is excellent in mechanical strength. When various compounding components are melt-kneaded with the polypropylene resin, the crystalline polypropylene resin (A) is melted, but the PTFE component is not melted but is fibrillated by a shearing force to take a fibrous network structure. This improves the melt tension of the molten resin and exhibits the effect of preventing drip.

  In order to describe the present invention more specifically, examples are shown below, but the present invention is not limited thereto. Unless otherwise specified, the parts shown in the examples are parts by weight.

Various physical properties were evaluated by the following methods.
(1) MFR (melt flow rate)
It was based on JIS-K6921-2: 1997 appendix (230 degreeC, 21.18N load).
(2) Isotactic pentad fraction [mmmm]
^{The 13} C-NMR method was followed.
(3) Flame retardancy:
The vertical combustion test method stipulated in the UL94V test (Underwriters Laboratories) “Plastic material combustion test for equipment parts” was used.
(4) Dripping property (drip property):
In accordance with the vertical combustion test method defined in the “flammability test of plastic materials for equipment parts” of the UL94V test (Underwriter Laboratories Corp.), the evaluation was made according to the following criteria. That is,
◎: There is no dropped material. ○: There is a dropped material. However, cotton is not ignited (drip 1).
×: Massive dripping material that ignites cotton (Drip 2)
(5) Appearance evaluation:
The foreign matters on the 120 mm × 120 mm × 2 mm injection molded sheet were visually observed and evaluated according to the following criteria. That is,
○: No white foreign matter was observed. Δ: One to ten white foreign matters of 0.1 mm or more could be observed. X: Eleven white foreign matters of 0.1 mm or more could be observed. (6) Flexural modulus. It measured at 23 degreeC based on JIS-K7203. The dimension of the molded product was 90 × 10 × 4 mm. Unit: MPa.

<Production of crystalline polypropylene resin (A)>
[Production Example 1] ... (A1) (Production of Ziegler catalyst)
Into a 10-liter reactor sufficiently purged with nitrogen, 4000 ml of dehydrated and deoxygenated n-heptane was introduced, and then 8 moles of MgCl ₂ and 16 moles of Ti (On-C ₄ H ₉ ) ₄ were introduced. For 2 hours. After completion of the reaction, the temperature was lowered to 40 ° C., and then 960 ml of methylhydropolysiloxane (20 centistokes) was introduced and reacted for 3 hours. The resulting solid component was washed with n-heptane. Next, 1000 ml of n-heptane purified in the same manner as described above was introduced into a 10 L reactor sufficiently purged with nitrogen, and 4.8 mol of the solid component synthesized above was introduced in terms of Mg atoms. Next, 8 mol of SiCl ₄ was mixed with 500 ml of n-heptane, introduced into the flask at 30 ° C. for 30 minutes, and reacted at 70 ° C. for 3 hours. After completion of the reaction, washing with n-heptane was performed. Subsequently, 0.48 mol of phthalic acid chloride was mixed with 500 ml of n-heptane, introduced into the flask at 70 ° C. for 30 minutes, and reacted at 90 ° C. for 1 hour. After completion of the reaction, washing with n-heptane was performed. Next, 200 ml of SiCl ₄ was introduced and reacted at 80 ° C. for 6 hours. After completion of the reaction, it was sufficiently washed with n-heptane to obtain a solid component. The titanium content of this product was 1.3% by weight.

Next, 1000 ml of n-heptane purified in the same manner as described above was introduced into a sufficiently nitrogen-substituted flask, 100 g of the solid component synthesized above was introduced, and (t-C ₄ H ₉ ) Si (CH ₃ ) ( 24 ml of OCH ₃ ) _{2 and} 34 grams of Al (C ₂ H ₅ ) ₃ were contacted at 30 ° C. for 2 hours. After completion of the contact, the catalyst was thoroughly washed with n-heptane to obtain a solid catalyst component mainly composed of magnesium chloride. The titanium content of this product was 1.1% by weight.

(Production of propylene block copolymer)
Using the solid catalyst component obtained above and triethylaluminum, propylene under the conditions of a polymerization temperature of 85 ° C. and a propylene partial pressure of 22 kg / cm ² using a fluidized bed gas phase reactor having a reaction volume of 280 L as the first polymerization step. Homopolymerization was performed continuously. At this time, the solid catalyst component was continuously supplied at a rate of 1.2 g / hr and triethylaluminum was continuously supplied at a rate of 5.5 g / hr. The powder extracted from the first polymerization step is continuously fed at 24 kg / hr to a fluidized bed gas phase reactor having a reaction part volume of 280 L used as the second polymerization step, and propylene and ethylene are continuously copolymerized. It was. A polymer of 30 kg / hr was continuously extracted from the second polymerization step. The molecular weight was controlled by controlling the hydrogen concentration in each polymerization step to the first tank H ₂ /C3=0.03 molar ratio and the second tank H ₂ /(C2+C3)=0.01 molar ratio. The ethylene composition in the rubbery propylene / ethylene copolymer is a propylene / ethylene block copolymer (A1) by controlling the propylene / ethylene gas composition in the second polymerization step to a propylene / ethylene = 1/1 molar ratio. Got. [Mmmm] was 0.98, and MFR was 30 g / 10 min.

[Production Example 2] ... Production of (A2) (Production of Ziegler catalyst)
To a 500-ml glass three-necked flask (with a thermometer, a dropping funnel, and a stirring rod) purged with nitrogen, 144 ml of purified heptane and 58 ml of titanium tetrachloride were added. The dropping funnel was charged with 120 ml of heptane and 66 ml of diethylaluminum chloride. The flask is cooled to −10 ° C., and diethylaluminum chloride is added dropwise over 3 hours under stirring at 120 rpm. Furthermore, after reacting at -10 ° C for 1 hour, the temperature of the system was slowly raised to 65 ° C in 1 hour. After reacting at 65 ° C. for 1 hour, the supernatant was separated by decantation and washed 5 times with 200 ml of fresh purified heptane. Next, 250 ml of heptane and 99 ml of diisoamyl ether were added and reacted at 35 ° C. for 1 hour. After completion of the reaction, it was washed 5 times with 200 ml of purified heptane in the same manner as in the previous reduction of titanium tetrachloride. Next, 150 ml of heptane and 116 ml of titanium tetrachloride were added and reacted at 65 ° C. for 2 hours. After completion of the reaction, washing was performed 5 times with 200 ml of purified heptane. Finally, 150 ml of heptane and 2.3 ml of n-butanol were added, reacted at room temperature for 1 hour, washed 3 times with 200 ml of heptane to obtain a solid catalyst component.

(Propylene polymerization)
After thoroughly replacing the 200-liter stirred autoclave with propylene, introduce 63 liters of fully dehydrated and deoxygenated n-heptane, mix diethylaluminum monochloride and ethylaluminum dichloride, and stir at room temperature for 2 hours. Then, 50 g of ethylaluminum chloride prepared by homogenization and 10 g of the titanium trichloride composition were introduced at 65 ° C. in a propylene atmosphere. The first stage polymerization was started by heating the autoclave to 70 ° C. and then introducing propylene at a flow rate of 9 kg / hr while adjusting the hydrogen concentration to 5 vol%. After 202 minutes, the introduction of propylene was stopped, and the polymerization was further continued at 70 ° C. for 90 minutes. Vapor phase propylene was purged to 0.2 kg / cm ² G. The second stage polymerization was carried out for 60 minutes by lowering the temperature of the autoclave to 65 ° C., and then introducing propylene at 4.6 kg / hr and ethylene at 3 kg / hr.

  The slurry thus obtained was filtered and dried to obtain a powdery propylene / ethylene block copolymer. [Mmmm] of the copolymer was 0.95, and MFR was 30 g / 10 min.

<Phosphorus flame retardant>
(B1) “ADK STAB FP2000” manufactured by Asahi Denka Co., Ltd. was used as a phosphate flame retardant. As physical properties of the flame retardant, there is no melting point (decomposes at 250 ° C. or higher), a nitrogen content of 20 to 23% by weight, and a phosphorus content of 18 to 21% by weight.
(B2) “Leoguard 1000” melting point 190 to 195 ° C. manufactured by Great Lakes was used as a phosphate ester flame retardant.

<PTFE flame retardant>
(C1) Masterbatch made of acrylic modified PTFE as raw material Polypropylene (Nippon Polychem, Propylene homopolymer powder: FY4
Equivalent product, MFR 5 g / 10 min.) 60 parts by weight, acrylic modified PTFE (Mitsubishi Rayon Co., Ltd., Metabrene A3000, PTFE content 20%) 40 parts by weight (PTFE 8 parts by weight), and stabilizer as penta Erythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate 0.05%, tris (2,4-di-t-butylphenyl) phosphite 0.05%, calcium stearate 0.05% of each was put into a tumbler mixer and mixed for 20 minutes. Then, it melt-kneaded and pelletized on the conditions of the temperature of 200 degreeC using the biaxial extruder (Ikegai company make, 45mmD, L / D = 38.5).

(C2) Master batch polypropylene made from unmodified PTFE (produced by Nippon Polychem, propylene homopolymer powder: FY4 equivalent, MFR 5 g / 10 min), 90 parts by weight, unmodified PTFE (produced by Daikin, Polyflon FA500, PTFE) (Content 100%) Except for using 10 parts by weight, the mixture was melt-kneaded and pelletized under the same conditions as in (C1) above.

  (C3) A powdery product of acrylic modified PTFE (Mitsubrene A3000 manufactured by Mitsubishi Rayon Co., Ltd.) was used as it was.

<Metal oxide>
(D1) to (D4)
Zinc oxide, iron oxide or aluminum oxide having various particle sizes was used.

  [Table 1] summarizes the physical properties and product names of the above raw materials.

<Example 1>
100 parts by weight of (A1) obtained above as a polypropylene resin, 28 parts by weight of (B1) as a phosphate-based flame retardant, 1.25 parts by weight of (C1) as a PTFE masterbatch (0.005 as PTFE). 1 part by weight), and as other additives, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (manufactured by Ciba Specialty Chemicals, Inc., antioxidant Irganox 1010) ) 0.2 parts by weight, Tris (2,4-di-t-butylphenyl) phosphite (manufactured by Ciba Specialty Chemicals, Inc., processing stabilizer Irgaphos 168), 0.2 parts by weight, and calcium stearate 0.05 Each part by weight was placed in a Henschel mixer and stirred for 3 minutes. The obtained mixture was melt-kneaded and extruded at 200 ° C. using a biaxial extruder having a diameter of 30 mm, and pelletized. The obtained pellets were dried at 80 ° C. for 4 hours, and then using an injection molding machine with a clamping pressure of 100 t, a test piece for UL94V having a thickness of 1.5 mm under the setting conditions of a molding temperature of 200 ° C. and a mold cooling temperature of 40 ° C. It was created. Further, an injection molded sheet of 120 mm × 120 mm × 2 mm was molded under the same conditions and used for appearance evaluation.

  Table 2 shows the formulation of the flame retardant polypropylene resin composition and the results of flame retardant evaluation of the composition.

<Examples 2 to 11>
Using the blending raw materials shown in Table 1, according to the blending recipe shown in Table 2, other additives were blended in the same manner as in Example 1, and the mixture was pelletized by stirring, mixing and melt-kneading. Table 2 shows the results of flame retardant evaluation conducted by preparing test pieces from the obtained pellets.

<Comparative Examples 1-5>
Using the blending raw materials shown in Table 1, according to the blending recipe shown in Table 3, other additives were blended in the same manner as in Example 1, and the mixture was pelletized by stirring, mixing and melt-kneading. Table 3 shows the results of flame retardant evaluation performed by preparing test pieces from the obtained pellets.

From the comparison of Table 2 and Table 3, the following became clear.
(1) Excellent flame retardancy is not achieved unless a PTFE flame retardant is blended (Comparative Example 1).
(2) Inferior in crystallinity ([mmmm] = 0.95) When a polypropylene resin is used as a raw material, excellent flame retardancy is not achieved (Comparative Example 2).
(3) When a phosphate ester flame retardant is blended in place of the phosphate flame retardant, excellent flame retardancy is not achieved (Comparative Examples 3 and 4).
(4) When a PTFE powder product is blended in place of the PTFE master batch (melt kneaded product), excellent flame retardancy is not achieved (Comparative Examples 5 and 6).

  According to the present invention, in addition to the excellent mechanical strength and moldability of polypropylene resin, excellent flame retardancy can be obtained, so it can be used in a wide range of fields such as automobile parts, electrical parts, container packaging members, and building members. Is possible.

Claims (7)

  Based on 100 parts by weight of the total amount of crystalline polypropylene resin (A) and phosphate flame retardant (B) having an MFR of 0.1 to 80 g / 10 min and an isotactic pentad fraction of 0.97 or more A flame retardant polypropylene resin composition obtained by melt-kneading 0.01 to 3 parts by weight of a master batch (C) obtained by melt-kneading tetrafluoroethylene resin (hereinafter abbreviated as PTFE) as PTFE.   The flame-retardant polypropylene resin composition according to claim 1, wherein the MFR of the crystalline polypropylene resin (A) is 5 to 60 g / 10 min.   PTFE with respect to a total amount of 100 parts by weight of crystalline polypropylene resin (A) and phosphate flame retardant (B) having an MFR of 5 to 60 g / 10 min and an isotactic pentad fraction of 0.97 or more. A flame retardant polypropylene resin composition obtained by melt-kneading 0.01 to 3 parts by weight of PTFE as a master batch (C) obtained by melt-kneading and 0.05 to 5 parts by weight of a metal oxide (D).   The flame retardant polypropylene resin composition according to claim 3, wherein the metal oxide is zinc oxide.   The flame-retardant polypropylene according to any one of claims 1 to 4, wherein 22 to 30 parts by weight of a phosphate flame retardant (B) is blended with 100 parts by weight of the crystalline polypropylene resin (A). Resin composition.   The flame retardant polypropylene resin composition according to any one of claims 1 to 5, wherein the resin matrix of the master batch (C) obtained by melt-kneading PTFE is a polypropylene resin. The flame retardant polypropylene resin composition according to any one of claims 1 to 6, wherein PTFE in the master batch (C) is acrylic-modified.