JP2005171169A - Polypropylene resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene resin composition giving a molded article having extremely small amounts of metal components, chlorine component and volatile components. <P>SOLUTION: It has been found that a propylene polymer produced by using a specific metallocene catalyst has extremely low residual metal content and chlorine content and, accordingly, the metal component and chlorine component eluted from a molded product can be decreased and the amount of generating gas can be reduced by using the propylene polymer requiring minimized amount of a neutralization agent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a propylene resin composition having a small amount of metal components and chlorine present in a polymer. Specifically, the present invention relates to a propylene resin composition having a metal component, chlorine, an n-decane soluble component, and a low volatile content.

  Propylene resins are widely used in various applications such as various industrial materials, containers, daily necessities, films, and fibers because of their excellent characteristics such as light weight, heat resistance, high transparency, and chemical resistance. However, a propylene-based polymer obtained by polymerization in the presence of a conventional Ziegler-Natta type catalyst always contains a large amount of chlorine due to the nature of the catalyst. Such residual chlorine has a function of accelerating the deterioration of the propylene-based polymer. Therefore, it is necessary to add a hydrochloric acid absorbent called a neutralizing agent.

  Commonly used as the neutralizing agent are metal salts such as calcium stearate, magnesium stearate, zinc stearate, calcium carbonate, magnesium hydroxide, anion exchange layered compounds such as hydrotalcite, and the like.

  However, when these neutralizing agents are used, the amount of metal components contained in the propylene resin increases, and therefore, the use of propylene resin for precision parts (insulating materials, etc.) has been hindered. Also, in certain solvents, these metal components and chlorine contained in the propylene resin dissolve out, so their use in applications that dislike elution of these components (medical fields, ink cartridges, beverage containers, etc.) has also been restricted. It was.

  In addition, low molecular weight components and low regularity components have always been by-produced in propylene-based polymers obtained with conventional Ziegler-Natta type catalysts. These low molecular weight components and low regularity components are known to cause sticky haze on the product surface and cause deterioration of blocking properties. Furthermore, it is known that volatile components such as solvent remaining in the polymer cause not only smoke and nasty odor during processing, but also various problems such as adversely affecting the odor and taste after processing. . Volatile components derived from these low molecular weight components, low regularity components, solvents and the like have also hindered the use of propylene resin in precision parts and food applications.

  JP-A-10-36589 is known as a measure for removing residual chlorine in a propylene polymer using a Ziegler-Natta catalyst. However, even if this method is used, chlorine remains in the polymer. A considerable amount of neutralizing agent had to be added.

  In addition, in Japanese Patent Laid-Open No. 2003-137929 relating to polypropylene produced with a metallocene catalyst, the amount of aluminum and chlorine contained in the propylene polymer are regulated, but there is a large amount of calcium stearate added as a neutralizing agent. For this reason, the amount of residual metal components increases.

On the other hand, a method of washing and removing low molecular weight components after polymerization (JP-B 53-4107, JP-B 58-41283, etc.), and a method of separating and removing a liquid layer portion after bulk polymerization (Japanese Patent Laid-Open No. 10-17612). Japanese Patent Laid-Open No. 10-17613, etc.) have been proposed, but the oligomer component amount and volatile component amount of the copolymer obtained by any of the methods were not at a sufficient level.
Japanese Patent Laid-Open No. 10-36589 JP 2003-137929 A Japanese Examined Patent Publication No. 53-4107 Japanese Patent Publication No.58-41283 Japanese Patent Laid-Open No. 10-17612 Japanese Patent Laid-Open No. 10-17613

  An object of the present invention is to provide a polypropylene resin composition or a molded article having an extremely low metal component, chlorine component and volatile content.

As a result of various studies conducted by the present inventors,
-The amount of residual metal and chlorine in the propylene polymer obtained with a certain metallocene catalyst is extremely small, and as a result, the amount of neutralizing agent can be reduced to the limit,
・ Using the propylene-based polymer obtained in this way, the metal components and chlorine content eluted from the product can be reduced, and the generated gas can be reduced.
And the present inventors have completed the polypropylene resin composition of the present invention. That is, each of aluminum, magnesium, calcium, titanium and zirconium present in the polypropylene resin composition is 10 ppm by weight or less, the total of all metal components is 15 ppm by weight or less, and the chlorine content is 3 ppm by weight or less. The polypropylene resin composition is preferably a polypropylene resin composition in which the amount of soluble part of n-decane (hereinafter sometimes referred to as nC ₁₀ ) present in polypropylene is 1% by weight or less. . A more preferable form is a polypropylene resin composition in which the total amount of volatile components in the polypropylene resin composition is 10 ppm by weight or less. The polypropylene resin composition as described above according to the present invention can be used for various molding applications such as injection molding, blow molding, film molding and fiber molding.

The polypropylene resin composition of the present invention has a metal component, chlorine, nC ₁₀ soluble part, and a small amount of volatile matter. Therefore, when used as a container for transporting and storing precision products, It is suitable for a silicon wafer container, a semiconductor cleaning container, and the like. Further, the metal component eluted from the composition is extremely small, and it is also effective for applications such as an ink cartridge.

  Hereinafter, the polypropylene resin composition (P) of the present invention will be described in detail.

The polypropylene resin composition (P) of the present invention is characterized by simultaneously satisfying the following 1) to 3).
[1] The content of aluminum, magnesium, calcium, titanium, and zirconium measured by ICP method is 10 ppm by weight or less, preferably the content of aluminum is 8 ppm by weight or less, the content of calcium is 1 ppm by weight or less, magnesium The titanium and zirconium contents are all 0.1 ppm by weight or less.
[2] The total sum of the metals is 15 ppm by weight or less, preferably 13 ppm by weight or less, more preferably 10 ppm by weight or less.
[3] The amount of chlorine measured by ion chromatography is 3 ppm by weight or less, preferably 2 ppm by weight or less, more preferably 1 ppm by weight or less.
The preferred form (P _A ) of the polypropylene resin composition of the present invention satisfies the following requirement [4] in addition to the above requirements [1] to [3].
[4] The amount of n-decane soluble part present in the polypropylene resin composition is 1% by weight or less, preferably 0.8% by weight or less.
In the polypropylene resin composition of the present invention, a more preferable form (P _B ) further satisfies the following requirement [5] in addition to the above requirements [1] to [4].
[5] The total amount of volatile components measured by the headspace gas chromatograph method is 10 ppm or less, preferably 8 ppm by weight or less, more preferably 5 ppm by weight or less.
Of the polypropylene resin composition of the present invention, a particularly preferred form (P _C) in addition to the requirements of the above-mentioned [1] to [5], which meets the following requirements [6].
[6] Hydrochloric acid detected when gas generated by heating at 230 ° C. for 60 minutes is collected with water is 5 ppb or less.
Further, the polypropylene resin composition _{(P, P A, P B} , P C) is preferably used for the following requirements [7] When meets various applications.
[7] Of the eluted components measured by CFC, the total amount of components eluted at a temperature of (melting point−60) ° C. or lower is 10% by weight or less, preferably 7% by weight or less, more preferably, based on the total dissolved amount. 5% by weight or less.

  The propylene polymer constituting the polypropylene resin composition of the present invention is a polymer obtained with a metallocene catalyst. As the metallocene catalyst, a known catalyst can be used without limitation, but a metallocene compound represented by the following general formula (1) or (2) is preferably used.

(In the formula, R ³ is selected from a hydrocarbon group and a silicon-containing hydrocarbon group, and R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ^{11 are selected.} , R ¹² , R ¹³ , and R ¹⁴ may be the same or different from each other, and are selected from a hydrogen atom, a hydrocarbon group, and a silicon-containing hydrocarbon group, and are adjacent to each other among the groups represented by R ¹ to R ¹² The groups may be bonded to each other to form a ring. In the case of the general formula (1), a group selected from R ¹ , R ⁴ , R ⁵ and R ¹² and R ¹³ or R ¹⁴ are bonded to each other to form a ring. A represents a divalent hydrocarbon group having 2 to 20 carbon atoms which may contain an unsaturated bond and / or an aromatic ring, and A includes a ring formed with Y. It may contain two or more ring structures, Y is a carbon atom or a silicon atom, M represents a service selected from Group 4 of the periodic table, and j is an integer of 1 to 4 , Q, ha Gen atom, a hydrocarbon group, selected from a neutral ligand capable of coordination with an anionic ligand and a lone pair, when j is 2 or more Q may be the same or different)
The said metallocene compound can also be used individually by 1 type or in combination of 2 or more types.

  The metallocene compound as described above can also be used by being supported on a particulate carrier.

Examples of such particulate carriers include inorganic carriers such as SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , MgO, ZrO ₂ , CaO, TiO ₂ , ZnO, SnO ₂ , BaO, and ThO, polyethylene, and propylene-based blocks An organic carrier such as a copolymer, poly-1-butene, poly-4-methyl-1-pentene, or a styrene / divinylbenzene copolymer can be used. These particle carriers can be used alone or in combination of two or more.

Of these carriers, SiO ₂ is preferably used.

  In the present invention, as one of the promoters of the metallocene catalyst, an organoaluminum oxy compound such as methylaluminoxane, a fluorine-containing boron compound, or the like can be used as a promoter.

  The metallocene catalyst used in the present invention is preferably prepolymerized before the main polymerization. As monomers used for prepolymerization, α-olefins such as ethylene, propylene, 1-butene and 1-hexene are used.

  The prepolymerization is desirably performed so that 0.01 to 1000 g, preferably 0.1 to 100 g of a polymer is formed per 1 g of the solid catalyst.

  The polymerization reaction is performed in the presence or absence of an inert hydrocarbon such as hexane, heptane, or cyclohexane, or a solvent such as a liquefied α-olefin.

  In the present invention, it is desirable to increase the amount of polymer produced per catalyst as much as possible.

  The polypropylene in the present invention means a propylene homopolymer or a copolymer of propylene and ethylene and / or an α-olefin having 4 to 20 carbon atoms. Specific examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1 -Octadecene, 1-eicosene and the like. Of these, ethylene and α-olefins having 4 to 10 carbon atoms are preferable, and ethylene and 1-butene are particularly preferable.

  In the present invention, after the polymerization is completed, the obtained polypropylene resin can be washed with an inert saturated hydrocarbon solvent such as propane, butane, hexane, heptane, or liquid α-olefin. The washing method is not particularly limited, and a known method such as decantation of the supernatant after the contact treatment in the stirring tank, countercurrent washing, or separation from the washing solution by a cyclone can be used. Moreover, you may add a quenching agent before washing | cleaning or simultaneously with washing | cleaning. There is no restriction | limiting in particular regarding a quencher, Water, alcohol, such as methanol and isopropanol, methyl ethyl ketone, or a mixture thereof can be used.

  In addition, a conventionally known method can be used in order to further remove a very small amount of chlorine contained in the polypropylene resin at the time of washing. As a method for removing chlorine, a method of contacting with an alkylene oxide, particularly preferably a method of contacting the alkylene oxide with water is effective.

  Drying the polypropylene resin obtained in the present invention is effective for removing volatile components contained in the resin. Although any conventionally known method can be used as the drying method, it is desirable to dry in a temperature range of 40 to 130 ° C, preferably 60 to 120 ° C. Although there is no restriction | limiting in particular in drying time, Generally, it implements in the range of 1 hour-48 hours.

  The melt flow rate (MFR: ASTM D1238, 230 ° C., 2.16 kg load) of the polypropylene resin of the polypropylene according to the present invention is preferably in the range of 0.5 to 60 g / 10 min, more preferably 3 to 40 g / 10 min. It is desirable to be within the range.

  In the polypropylene resin according to the present invention, additives that are usually used can be used within the range satisfying the amount of metal, volatile matter, and chlorine shown in the claims, if necessary. In general, phenolic antioxidants, phosphorus antioxidants, weathering stabilizers, antistatic agents, lubricants, neutralizing agents, nucleating agents, and the like can be added.

  The present invention makes it possible to produce polypropylene with very little residual chlorine by using a specific metallocene catalyst system, and without adding a neutralizing agent (calcium stearate, magnesium stearate, hydrotalcite, etc.). However, it can be used for applications such as containers for precision product transportation and storage, silicon wafer containers, semiconductor cleaning containers, and ink cartridges as described above. It is also possible to add a compatibilizer.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

In the following examples, the physical properties of the polymers are measured according to the following methods.
Metal analysis (quantification of aluminum, magnesium, titanium, calcium and zirconium components):
Samples 20 to 50 g were placed in a platinum crucible and incinerated on an electric stove. After complete ashing in an electric furnace at 750 ° C., the ashed product was melted with potassium pyrosulfate. This melt was dissolved in 2N sulfuric acid and adjusted to 50 ml to prepare a test solution. The test solution was analyzed by ICP to quantify a predetermined metal.
About 0.8 g of chlorine sample was burned with a combustion device (Mitsubishi Chemical QF-02, with concentrator), the generated gas was collected with water, and measured with an ion chromatograph (with DIONEX DX-300 concentrator). .
The sample of generated hydrochloric acid is heated at 230 ° C for 60 minutes in a special vessel through which nitrogen is supplied at a constant flow rate. The resulting gas is passed through water to collect chlorine, and an ion chromatograph (with DIONEX DX-300 concentrator). Measured with
The volatile matter analysis pellets were pulverized by a pulverizer, and 10 g of the pulverized pellets were placed in a headspace bottle and heated by a dryer at 110 ° C. for 1 hour. 0.5 ml of the gas phase part of the headspace bottle was injected into a gas chromatograph, and all detected volatile component peaks were quantified to obtain a total volatile content.
Gas Chromatograph Measurement Condition Column CBP-1 0.53 mmI. D. × 50m df = 0.5μm
The column temperature is maintained at 50 ° C. for 5 minutes, and then the temperature is raised to 140 ° C. at a rate of 7 ° C./min. After holding at 140 ° C. for 4 minutes, the temperature is raised to 180 ° C. at 7 ° C./minute and held for 10 minutes.
Carrier gas Helium detector FID

[Production of propylene polymer]
[1] Production of solid catalyst support 300 g of SiO ₂ (manufactured by Dokai Chemical Co., Ltd.) was sampled in a 1 L branch flask, and 800 mL of toluene was added to make a slurry. Next, the solution was transferred to a 5 L four-necked flask, and 260 mL of toluene was added. 2830 mL of a toluene solution of methylaluminoxane (hereinafter referred to as MAO) (10% by weight manufactured by Albemarle) was introduced. The mixture was stirred for 30 minutes while remaining at room temperature. The temperature was raised to 110 ° C. over 1 hour, and the reaction was carried out for 4 hours. After completion of the reaction, it was cooled to room temperature. After cooling, the supernatant toluene was extracted and replaced with fresh toluene, and the replacement was performed until the replacement rate reached 95%.
[2] Production of solid catalyst (support of metal catalyst component on support)
In a glove box, 2.0 g of isopropyl (3-t-butyl-5-methylcyclopentadienyl) (3,6-di-t-butylfluorenyl) zirconium dichloride was weighed in a 5 L four-necked flask. The flask was taken out, 0.46 liters of toluene and 1.4 liters of MAO / SiO ₂ / toluene slurry prepared in 1) were added under nitrogen, and the mixture was stirred for 30 minutes to carry. The resulting isopropyl (3-t-butyl-5-methylcyclopentadienyl) (3,6-di-t-butylfluorenyl) zirconium dichloride / MAO / SiO ₂ / toluene slurry was 99 in n-heptane. % Substitution was performed, and the final slurry amount was 4.5 L. This operation was performed at room temperature.
[3] Production of prepolymerization catalyst
Insert 202 g of the solid catalyst component prepared in [2], 109 mL of triethylaluminum, and 100 L of heptane into an autoclave with a stirrer with an internal volume of 200 L, keep the internal temperature at 15 to 20 ° C., insert 2020 g of ethylene, and react with stirring for 180 minutes. It was. After completion of the polymerization, the solid component was precipitated, and the supernatant was removed and washed with heptane twice. The obtained prepolymerized catalyst was resuspended in purified heptane and adjusted with heptane so that the solid catalyst component concentration was 2 g / L. This prepolymerized catalyst contained 10 g of polyethylene per 1 g of the solid catalyst component.
[4] Main polymerization: Propylene 45 kg / hour, hydrogen 13 NL / hour, catalyst slurry as solid catalyst component 2.5 g / hour, triethylaluminum 1.4 ml / hour continuously supplied to a 58 L tubular polymerizer. The polymerization was carried out in a full liquid state where no gas phase was present. The temperature of the tubular reactor was 30 ° C., and the pressure was 2.9 MPa / G.

  The obtained slurry was sent to a vessel polymerization vessel with a stirrer having an internal volume of 1000 L, and further polymerization was performed. To the polymerization reactor, propylene was supplied at 67 kg / hour and hydrogen was supplied at 36 NL / hour. Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 2.8 MPa / G.

  Furthermore, the obtained slurry was sent to a vessel polymerization vessel equipped with a stirrer having an internal volume of 500 L, and further polymerized. Propylene was supplied at 11 kg / hour and hydrogen was supplied at 11 NL / hour to the polymerization vessel. Polymerization was performed at a polymerization temperature of 68 ° C. and a pressure of 2.8 MPa / G.

  Furthermore, the obtained slurry was sent to a vessel polymerization vessel equipped with a stirrer having an internal volume of 500 L, and further polymerized. To the polymerization vessel, propylene was supplied at 14 kg / hour and hydrogen was supplied at 11 NL / hour. Polymerization was performed at a polymerization temperature of 67 ° C. and a pressure of 2.7 MPa / G.

  Furthermore, the obtained slurry was sent to a vessel polymerization vessel equipped with a stirrer having an internal volume of 500 L, and further polymerized. Propylene was supplied at 7 kg / hour and hydrogen was supplied at 4 NL / hour to the polymerization vessel. Polymerization was performed at a polymerization temperature of 66 ° C. and a pressure of 2.7 MPa / G. Polypropylene was obtained at 62 kg / hour and was 24.8 kg-PP / g-catalyst per unit catalyst.

  The obtained polypropylene was dried with a conical drier having an internal capacity of 3000 L at 80 ° C. for 10 hours at 70 mmHg.

  The obtained polypropylene had MFR = 24 g / 10 min.

  0.07 part by weight of Irganox 1010 (trademark) [phenolic antioxidant, manufactured by Ciba Geigy Co., Ltd.] was mixed with a Henschel mixer, and pelletized at 230 ° C. This polypropylene pellet had an excess weight of 2.16 kg and a melt flow index (hereinafter referred to as MFR) at 230 ° C. of 25. Table 1 shows the metal components contained in the pellet, the amount of chlorine, the amount of generated hydrochloric acid, the amount of n-decane soluble part, the total volatilization amount, the melting point, and the CFC elution amount up to (melting point−60) ° C.

[Comparative Example 1]
[Catalyst adjustment]
300 g of anhydrous magnesium chloride, 1.6 liters of kerosene, and 1.5 liters of 2-ethylhexyl alcohol were heated at 140 ° C. for 3 hours to obtain a uniform solution. 70 grams of phthalic anhydride was added to this solution and dissolved by stirring at 130 ° C. for 1 hour, followed by filtration using a sintered filter to remove a trace amount of impurities. The filter paper was cooled to room temperature. Further, the above filtrate was slowly dropped into 8.5 liters of titanium cooled to −20 ° C. or 8.5 liters of titanium. After completion of dropping, the temperature was raised to 110 ° C., 215 ml of diisobutyl phthalate was added, and the mixture was further stirred for 2 hours. The solid was separated by hot filtration, and the obtained solid was washed with n-heptane until substantially no titanium was detected in the washing solution. The obtained solid catalyst component contained 2.2 wt% titanium and 11.0 wt% diisobutyl phthalate.

[Polymerization and pelletization]
An autoclave with an internal volume of 700 liters, which had been sufficiently dried and replaced with nitrogen, was prepared. Milligram was added, 20 kg of propylene and 17 N liters of hydrogen were added, and polymerization was carried out at 70 ° C. for 2 hours. After polymerization, unreacted propylene was separated by decantation, and the polymerization product was washed three times with liquefied propylene.

  Next, 0.2 gram of water and 10 ml of propylene oxide were added to the product, further treated at 90 ° C. for 15 minutes, and dried under reduced pressure for 5 minutes. This treatment with propylene oxide was repeated three times, and the produced polymer was taken out and weighed to obtain 14.50 kilograms of polypropylene. The amount obtained per titanium by this polymerization was 4.39 million g-PP / g-Ti.

  0.05 parts by weight of calcium stearate (manufactured by NOF Corporation, chlorine content 156 ppm), 0.05 parts by weight of hydrotalcite, Irganox 1010 (trademark) [phenolic antioxidant, based on 100 parts by weight of the obtained polypropylene , Manufactured by Ciba Geigy Co., Ltd.] 0.07 part by weight was mixed with a Henschel mixer and pelletized at 230 ° C. The pellets were dried in a constant temperature dryer at 105 ° C. for 8 hours.

  This polypropylene pellet had an excess weight of 2.16 kg and a melt flow index (hereinafter referred to as MFR) at 230 ° C. of 9. Table 1 shows the metal components contained in the pellet, the amount of chlorine, the amount of generated hydrochloric acid, the amount of n-decane soluble part, the total volatilization amount, the melting point, and the CFC elution amount up to (melting point−60) ° C.

[Comparative Example 2]
Except that calcium stearate and hydrotalcite were not added and Irganox 1010 (trademark) [phenolic antioxidant, manufactured by Ciba Geigy Co., Ltd.] was mixed with 0.07 part by weight using a Henschel mixer, pelletized as in Comparative Example 1, Drying was performed. The results are shown in Table 1.

[Comparative Example 3]
The polymer obtained by using the catalyst of Comparative Example 1 was not subjected to propylene oxide treatment to obtain a polymer. Henschel mixer with 0.05 parts by weight of calcium stearate (manufactured by NOF Corporation, chlorine content 156 ppm), and 0.07 parts by weight of Irganox 1010 (trademark) [phenolic antioxidant, manufactured by Ciba Geigy Co., Ltd.] per 100 parts by weight of polypropylene And pelletized at 230 ° C. The obtained pellets were not dried. The results are shown in Table 1.

[Comparative Example 4]
Except that calcium stearate was not added and Irganox 1010 (trademark) [phenolic antioxidant, manufactured by Ciba Geigy Co., Ltd.] in an amount of 0.07 part by weight was mixed with a Henschel mixer, pelletized and dried in the same manner as in Comparative Example 3. . The results are shown in Table 1.

Claims (5)

  The content of aluminum, magnesium, calcium, titanium and zirconium measured by ICP method is 10 ppm by weight or less, the total amount of the metals is 15 ppm by weight or less, and the chlorine content measured by ion chromatography is A polypropylene resin composition characterized by being 3 ppm by weight or less.   2. The polypropylene resin composition according to claim 1, wherein the amount of the n-decane soluble part present in the resin composition is 1% by weight or less.   3. The polypropylene resin composition according to claim 2, wherein the total amount of volatile components measured by a headspace gas chromatograph method is 10 ppm or less.   The polypropylene resin composition according to claim 3, wherein hydrochloric acid detected when the gas generated by heating at 230 ° C. for 60 minutes is collected with water is 5 ppb or less.   5. The total amount of components eluted at a temperature of (melting point−60) ° C. or less among the eluted components measured by CFC is 10% by weight or less with respect to the total eluted amount. 2. The polypropylene resin composition according to item 1.