JP5097529B2 - Propylene / ethylene resin composition and container comprising the same - Google Patents

Description

  The present invention relates to a propylene / ethylene resin composition and an injection-molded container, and more specifically, improved rigidity and impact resistance balance, high transparency, excellent whitening resistance, and does not cause deterioration of odor and the like. The present invention relates to a propylene / ethylene-based resin composition and an injection-molded container suitable for containers for food and medical use, which have few elution components.

  Crystalline polypropylene is widely used in various molding fields because of its excellent mechanical properties and chemical resistance. However, when a propylene homopolymer is used as crystalline polypropylene, rigidity is increased but impact resistance is insufficient. Therefore, impact resistance is improved by a method of adding an elastomer such as ethylene-propylene rubber to a propylene homopolymer or a method of producing a so-called block copolymer by copolymerizing ethylene and propylene after the homopolymerization of propylene. It has been done to improve. Although these methods can improve the physical properties to a considerable extent, it is desired to further improve the balance between rigidity and impact resistance. In addition to these properties, improvements in terms of product differentiation, such as improving transparency, improving heat resistance, and lowering the gloss unique to plastics, are strongly desired.

  For example, in order to improve flexibility and solve the deterioration of transparency, polypropylene or a polypropylene-ethylene copolymer having a low ethylene content in the first step in the polymerization reaction, and ethylene content in the second step in the first step There has been proposed a technique in which a relatively small amount of propylene-ethylene rubber, which is larger than the polymer obtained in (1), is continuously polymerized using a Ziegler-Natta catalyst (Patent Documents 1 and 2). However, since Ziegler-Natta catalysts have multiple types of active sites, the resulting ethylene-propylene copolymer has a wide crystallinity and molecular weight distribution, and produces many low crystals and low molecular weight components. And bleed-out are strongly observed, and problems such as blocking properties and poor appearance tend to occur. Furthermore, there are problems such as poor appearance of molded products due to gas generation during molding, odor, and adhesion / contamination of low molecular weight components to the mold.

On the other hand, it is known that isotactic polypropylene can be obtained by polymerizing propylene using a metallocene catalyst different from the conventional Ziegler-Natta catalyst. It is also known to produce a so-called block copolymer by copolymerizing ethylene and propylene after homopolymerization of propylene using the same catalyst (for example, Patent Documents 3 to 7). In addition, although propylene-ethylene block copolymers with improved rigidity and impact are known (for example, Patent Documents 8 to 11), further rigidity and impact resistance are improved, heat resistance, There is a need for improved moldability and appearance.
JP-A 63-159212 JP 63-168414 A JP-A-4-337308 JP-A-6-287257 Japanese Patent Laid-Open No. 5-202152 JP-A-6-206921 Japanese Patent Laid-Open No. 10-219047 Japanese Patent Laid-Open No. 11-228648 JP-A-11-240929 JP-A-11-349649 JP-A-11-349650

  The present invention solves the above-mentioned drawbacks, has a good molding process at the time of injection molding, has a low flexural modulus, low-temperature impact resistance, particularly less generation of elution components and odors, and has transparency and whitening resistance. An object of the present invention is to provide an excellent polypropylene-based resin composition suitable for food and medical injection-molded containers and the container.

  As a result of intensive studies to solve the above-described problems in the prior art, the present inventors have obtained two kinds of specific structures having different ethylene contents obtained by sequential polymerization using a metallocene catalyst. A composition consisting of a propylene / ethylene random copolymer, a relatively low amount of polymerized rubber, and a low molecular weight component and a propylene / ethylene copolymer and a nucleating agent provides a very good balance between rigidity and impact resistance. It has been found that an injection molded container having high transparency and whitening resistance, good appearance, and little elution and odor can be supplied.

That is, according to the first invention of the present invention, a propylene / ethylene random copolymer having an ethylene content of 1.5 to 5.0% by mass obtained by sequential polymerization using a metallocene catalyst ( I) A propylene / ethylene resin composition comprising 86 to 93% by mass and 7 to 14% by mass of a propylene / ethylene random copolymer (II) having an ethylene content of 15 to 35% by mass ,
For 100 parts by weight of the propylene-ethylene copolymer (A), an organic phosphate metal salt, an organic monocarboxylic acid metal salt, an organic dicarboxylic acid metal salt, a polymer nucleating agent, dibenzylidene sorbitol or a derivative thereof, or diterpenic acids It contains 0.05 to 0.15 parts by weight of one or more nucleating agents (B) selected from metal salts and 0.01 to 0.6 parts by weight of a neutralizing agent (C), and has a tert-butyl alcohol content. Is 0.5 ppm or less, and the total content of linear aliphatic carboxylic acids of C _{1 to} C ₁₃ measured with a gas chromatograph (GC) / mass spectrometer (MS) is 1 ppm or less and measured at 0 ° C. The propylene / ethylene resin composition is provided with an impact strength of 4.6 to 5.3 kJ / m ³ .

According to the second invention of the present invention, in the first invention, the propylene-ethylene copolymer (A) has an MFR (230 ° C., load 2.16 kg) of 5 to 100 g / 10 minutes, and A propylene / ethylene-based resin composition is provided in which the total content of components having a weight average molecular weight (Mw) of 3,000 or less is 1% by mass or less.

Moreover, according to the 3rd invention of this invention, the container obtained by injection-molding the propylene ethylene resin composition which concerns on either 1st or 2nd invention is provided.

  The propylene / ethylene-based resin composition of the present invention has excellent properties such as improved rigidity and impact resistance balance, high transparency, excellent whitening resistance, no odor deterioration, and few elution components. have. Therefore, a container obtained by injection molding can be suitably used as an injection container for food or medicine, for example, a dessert container such as pudding or yogurt, a container for food such as a mozuku container or a juice container.

The propylene / ethylene resin composition of the present invention is a propylene / ethylene random copolymer (I) having an ethylene content of 1.5 to 5.0% by mass obtained by sequential polymerization using a metallocene catalyst. A propylene / ethylene resin composition comprising 86 to 93% by mass and 7 to 14% by mass of a propylene / ethylene random copolymer (II) having an ethylene content of 15 to 35% by mass ,
For 100 parts by weight of the propylene-ethylene copolymer (A), an organic phosphate metal salt, an organic monocarboxylic acid metal salt, an organic dicarboxylic acid metal salt, a polymer nucleating agent, dibenzylidene sorbitol or a derivative thereof, or diterpenic acids It contains 0.05 to 0.15 parts by weight of one or more nucleating agents (B) selected from metal salts and 0.01 to 0.6 parts by weight of a neutralizing agent (C), and has a tert-butyl alcohol content. Is 0.5 ppm or less, and the total content of linear aliphatic carboxylic acids of C _{1 to} C ₁₃ measured with a gas chromatograph (GC) / mass spectrometer (MS) is 1 ppm or less and measured at 0 ° C. The impact strength is 4.6 to 5.3 kJ / m ³ .
The container of the present invention is obtained by injection molding this propylene / ethylene resin composition. The components of the propylene / ethylene resin composition of the present invention, the production method and the characteristics of the container will be described in detail below.

[I] Propylene / ethylene resin composition Propylene / ethylene block copolymer (A)
(1) Structure The propylene-ethylene random copolymer (A) constituting the propylene / ethylene-based resin composition of the present invention is a propylene / ethylene random copolymer having an ethylene content of 1.5 to 5.0% by mass ( I) and a propylene-ethylene random copolymer (A) comprising a propylene / ethylene random copolymer (II) having an ethylene content of 15 to 35% by mass, wherein the propylene / ethylene random copolymer (I) The ratio is in the range of 86 to 93% by mass, and the ratio of the propylene / ethylene random copolymer (II) is 7 to 14% by mass.

When the ethylene content of the propylene / ethylene random copolymer (I) is less than 1.5% by mass, the rigidity becomes high, but the impact resistance and flexibility are insufficient, and the transparency is poor and the whitening resistance is improved. Inferior. If it exceeds 5.0 mass%, the rigidity is insufficient. Further, when the ethylene content of the propylene / ethylene random copolymer (II) is less than 15% by mass, the low-temperature impact strength is insufficient and the rigidity is liable to decrease, and when it exceeds 35% by mass, the transparency is deteriorated and the whitening resistance is increased. Invite the deterioration. The ethylene content of the propylene / ethylene copolymer portion can be prepared by controlling the monomer composition of propylene and ethylene during polymerization.
Further, when the ratio of the propylene / ethylene random copolymer (II) is less than 7% by mass, the impact resistance is insufficient, and after the food is filled in the container, the product damage due to dropping increases in the low temperature distribution process. On the other hand, if it exceeds 14% by mass, the rigidity is insufficient, and when the lid that seals the container with a film is removed, the container is deformed and it becomes difficult to peel off.
The ratio of the propylene / ethylene copolymer (II) is determined based on the polymerization temperature, polymerization pressure, residence time, and raw material monomer composition of the first reactor or the second reactor at the time of polymerization using the metallocene catalyst described later. Polymerization conditions such as preparation can be prepared and set.

  Further, the MFR of the entire propylene-ethylene copolymer (A) is preferably 5 to 100 g / 10 minutes, and more preferably 5 to 80 g / 10 minutes. If the MFR is less than 5 g / 10 minutes, the moldability tends to be insufficient, which is not preferable. On the other hand, if it is excessively high, the mechanical properties are lowered and fragile. MFR can be controlled by the addition of a molecular weight regulator added during polymerization and the polymerization conditions of temperature and pressure.

The component having a weight average molecular weight Mw of 3,000 or less in the propylene-ethylene copolymer (A) preferably has a total content of 1% by mass or less. More preferably, it is 0.7 mass% or less. A component having a weight average molecular weight of 3,000 or less becomes a volatile component at the time of molding, and causes bleed deposits on the mold, gas generation, appearance defects, odor deterioration, and the like. In addition, production is interrupted to remove deposits on the mold, and productivity is deteriorated. In particular, in the case of a high-cycle thin-walled injection container, gas generation due to volatile components is not preferable because it generates heat due to rapid adiabatic compression of gas in the mold and causes burning problems during molding.
The amount of the component having a weight average molecular weight Mw of 3,000 or less can be controlled in various steps such as selection of a catalyst to be used at the time of producing a propylene-ethylene copolymer, a polymerization method, and a composition production method.

Here, the ratio of the propylene / ethylene random copolymer (II) and the propylene / ethylene content are values measured by the following CFC-IR method. The method is as follows.
(I) Analytical device to be used (a) Cross fractionation device CFC T-100 (abbreviated as CFC) manufactured by Dia Instruments Co., Ltd.
(B) Fourier transform infrared absorption spectrum analysis FT-IR, Perkin Elmer 1760X
A fixed wavelength infrared spectrophotometer attached as a CFC detector is removed and an FT-IR is connected instead, and this FT-IR is used as a detector. The transfer line from the outlet of the solution eluted from the CFC to the FT-IR is 1 m long, and the temperature is maintained at 140 ° C. throughout the measurement. The flow cell attached to the FT-IR has an optical path length of 1 mm and an optical path width of 5 mmφ, and the temperature is maintained at 140 ° C. throughout the measurement.
(C) Gel permeation chromatography (GPC)
The GPC column in the latter part of the CFC is used by connecting three AD806MS manufactured by Showa Denko KK in series.

(Ii) CFC measurement conditions (a) Solvent: orthodichlorobenzene (ODCB)
(B) Sample concentration: 4 mg / mL
(C) Injection volume: 0.4 mL
(D) Crystallization: The temperature is lowered from 140 ° C. to 40 ° C. over about 40 minutes.
(E) Sorting method:
The fractionation temperature at the time of temperature-raising elution fractionation is 40, 100, and 140 ° C., and the fraction is separated into three fractions in total. In addition, the elution ratio (unit: mass%) of the component eluting at 40 ° C. or lower (fraction 1), the component eluting at 40 to 100 ° C. (fraction 2), and the component eluting at 100 to 140 ° C. (fraction 3), respectively It is defined as W40, W100, and W140. W40 + W100 + W140 = 100. Moreover, each fractionated fraction is automatically transported to the FT-IR analyzer as it is.
(F) Solvent flow rate during elution: 1 mL / min

(Iii) Measurement conditions for FT-IR After elution of the sample solution from the GPC at the latter stage of the CFC starts, FT-IR measurement is performed under the following conditions, and GPC-IR data is collected for each of the above-described fractions 1 to 3. .
(A) Detector: MCT
(B) Resolution: 8 cm-1
(C) Measurement interval: 0.2 minutes (12 seconds)
(D) Accumulation count per measurement: 15 times (iv) Post-processing and analysis of measurement results The elution amount and molecular weight distribution of the components eluted at each temperature are the chromatogram of the absorbance at 2945 cm ⁻¹ obtained by FT-IR. Use as you seek. The elution amount is normalized so that the total elution amount of each elution component is 100%. Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene.
Standard polystyrenes used are the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000.
A calibration curve is created by injecting 0.4 mL of a solution dissolved in ODCB (containing 0.5 mg / mL BHT) so that each is 0.5 mg / mL. The calibration curve uses a cubic equation obtained by approximation by the least square method.

Conversion to molecular weight uses a general-purpose calibration curve with reference to “Size Exclusion Chromatography” written by Sadao Mori (Kyoritsu Shuppan). The following numerical values are used for the viscosity equation ([η] = K × Mα) used at that time.
(A) At the time of creating a calibration curve using standard polystyrene K = 0.000138, α = 0.70
(B) When measuring a sample of a propylene-based block copolymer K = 0.000103, α = 0.78
The molecular weight of each elution portion subjected to the elution fractionation is defined as Mw (40), Mw (100), and Mw (140). The total molecular weight distribution was calculated by summing up the data obtained by three fractions. From this, the content (mass%) of the component whose weight average molecular weight mentioned later is 3,000 or less is obtained by integration.
In addition, the ethylene content distribution (distribution of ethylene content along the molecular weight axis) of each eluted component is a ratio between the absorbance of 2956 cm ^{−1 and} the absorbance of 2927 cm ⁻¹ obtained by FT-IR, and is obtained from polyethylene or polypropylene. The ethylene content (mass%) was determined by using a calibration curve prepared in advance using ethylene, propylene rubber (EPR) and mixtures thereof whose ethylene content is already known by 13C-NMR measurement or the like. Calculate by conversion.

The ratio (Wc) of the propylene / ethylene random copolymer part (EP) in the propylene / ethylene block copolymer in the present invention is theoretically defined by the following formula (I) using the result measured by the above method. The following procedure is required.
Wc (mass%) = W40 × A40 / B40 + W100 × A100 / B100 (I)
In formula (I), W40 and W100 are the elution ratios (unit: mass%) in each of the above-mentioned fractions, and A40 and A100 are the average ethylene content of actual measurement in each fraction corresponding to W40 and W100. (Unit: mass%), and B40 and B100 are the ethylene content (unit: mass%) of EP contained in each fraction. A method for obtaining A40, A100, B40, and B100 will be described later.
The meaning of the formula (I) is as follows. That is, the first term on the right side of the formula (I) is a term for calculating the amount of EP contained in fraction 1 (portion soluble at 40 ° C.). When fraction 1 contains only EP and no propylene homopolymer part (PP), W40 contributes to the EP content derived from fraction 1 as a whole, but fraction 1 is derived from EP. Since a small amount of PP-derived components (extremely low molecular weight components and atactic polypropylene) are included in addition to the components, it is necessary to correct the portion. Therefore, by multiplying W40 by A40 / B40, the amount derived from the EP component in fraction 1 is calculated. For example, when the average ethylene content (A40) of fraction 1 is 30% by mass and the ethylene content (B40) of EP contained in fraction 1 is 40% by mass, 30/40 = 3/4 of fraction 1 (Ie, 75% by mass) is derived from EP, and 1/4 is derived from PP. Thus, the operation of multiplying A40 / B40 by the first term on the right side means that the contribution of EP is calculated from the mass% (W40) of fraction 1. The same applies to the second term on the right side, and for each fraction, the EP content is calculated by adding and adding the EP contribution.

Here, the calculation is performed in consideration of the following conditions.
(A) As mentioned above, the average ethylene content corresponding to fractions 1-2 obtained by CFC measurement is A
40 and A100 (the unit is mass%). A method for obtaining the average ethylene content will be described later.
(B) The ethylene content corresponding to the peak position in the differential molecular weight distribution curve of fraction 1 is defined as B40 (unit is mass%). Fraction 2 is considered to be substantially defined as B100 = 100 in the present invention because it is considered that the rubber part is completely eluted at 40 ° C. and cannot be defined with the same definition. B40 and B100 are ethylene contents of EP contained in each fraction, but it is practically impossible to obtain this value analytically. The reason is that there is no means for completely separating and separating PP and EP mixed in the fraction. As a result of investigations using various model samples, B40 can explain the effect of improving material properties well when the ethylene content corresponding to the peak position of the differential molecular weight distribution curve of fraction 1 is used. That is, B40 is the ethylene content corresponding to the peak position of the differential molecular weight distribution curve of fraction 1. B100 has crystallinity derived from ethylene chain, and the amount of EP contained in these fractions is relatively small compared to the amount of EP contained in fraction 1. Is closer to the actual situation, and almost no error occurs in the calculation. So B
Analysis is performed with 100 = 100.
(C) For the above reason, the EP ratio (Wc) is obtained according to the following formula (II).
Wc (mass%) = W40 × A40 / B40 + W100 × A100 / 100 (II)
That is, W40 × A40 / B40, which is the first term on the right side of the formula (II), indicates the EP content (% by mass) having no crystallinity, and W100 × A100 / 100, which is the second term, represents the crystallinity. The EP content (% by mass) is shown.

Here, average ethylene content A40, A100 of each fraction 1 and 2 obtained by B40 and CFC measurement is calculated | required as follows.
The ethylene content corresponding to the peak position of the differential molecular weight distribution curve is defined as B40. In addition, the sum of the products of the weight ratio for each data point and the ethylene content for each data point taken as data points at the time of measurement is defined as the average ethylene content A40 of fraction 1. The average ethylene content A100 of fraction 2 is determined in the same manner.
The significance of setting the three types of fractionation temperatures is as follows. In the CFC analysis of the present invention, 40 ° C. means only a polymer having no crystallinity (for example, most of EP or a component having extremely low molecular weight and atactic component in propylene homopolymer portion (PP)). It has the meaning that it is a temperature condition necessary and sufficient for fractionation. 100 ° C. is a component that is insoluble at 40 ° C. but becomes soluble at 100 ° C. (eg, a component having crystallinity due to a chain of ethylene and / or propylene and PP having low crystallinity in EP) The temperature is necessary and sufficient to elute only. 140 ° C. is a component that is insoluble at 100 ° C. but becomes soluble at 140 ° C. (for example, a component having particularly high crystallinity in PP, and a component having extremely high molecular weight and extremely high ethylene crystallinity in EP ) Only, and the temperature is necessary and sufficient to recover the entire amount of the propylene-based block copolymer used for the analysis. W140 does not contain any EP component, or even if it is present, it is very small and can be substantially ignored. Therefore, it is excluded from the calculation of the ratio of EP and the ethylene content of EP.

The ethylene content of the propylene / ethylene random copolymer part (EP) in the propylene / ethylene block copolymer in the present invention is obtained by the following formula (III) using the result measured by the above method.
Ethylene content (% by mass) of EP = (W40 × A40 + W100 × A100) / Wc (III)
(Wc is the ratio (mass%) of EP obtained previously.)

(2) Production of propylene / ethylene block copolymer The production of the propylene / ethylene block copolymer (A) in the present invention comprises a metallocene complex and an organoaluminum oxy compound, a Lewis acid, an anionic compound or a clay mineral, so-called A metallocene catalyst is used.

  As a metallocene compound having high stereoregularity in a metallocene catalyst, a group 4 having a carbon bridge, a silicon bridge, a germane bridge group, and a substituted or unsubstituted cyclopentadiene, indene, fluorene, or azulene as a ligand The transition metal compound can be mentioned. The following are non-limiting specific examples.

(I) Examples of carbon bridges include ethylene bis (2,4-dimethylindenyl) zirconium chloride, ethylenebis (2,4,7-trimethylindenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (fluorenyl) zirconium. Examples thereof include chloride, isopropylidene (3-methylindenyl) (fluorenyl) zirconium chloride, isopropylidene (2-methylcyclopentadienyl) (3-methylindenyl) zirconium dichloride, and the like.
(Ii) Examples of the silicon bridge include dimethylsilylene bis (2-methyl, 4-phenylindenyl) zirconium dichloride, diphenylsilylene (2-ethyl, 4-phenylindenyl) zirconium dichloride, dimethylsilylene bis (2-methylbenzoindene). Nyl) zirconium dichloride, dimethylsilylene bis (2-isopropyl, 4- (3,5-diisopropylphenyl) indenyl) zirconium dichloride, dimethylsilylene bis (2-propyl, 4-phenanthryl, indenyl) zirconium dichloride, dimethylsilylene bis (2 -Ethyl, 4- (4-tertbutyl, 3-chloro, phenyl) azurenyl) zirconium dichloride and the like.
(Iii) As the germane crosslinking, a compound in which the above (ii) silicon-crosslinked silylene is replaced with germanylene is used. A compound in which zirconium is replaced with hafnium is exemplified as a suitable compound as it is. Furthermore, the dichloride of the exemplified compound can be exemplified by other halides, compounds substituted with methyl group, isobutyl group, phenyl group, hydride group, dimethylamide, diethylamide group, etc. as suitable compounds.

In the metallocene catalyst system, organoaluminum oxy compounds, Lewis acids, ionic compounds, and clay minerals can be used as co-catalysts.
Non-limiting examples of (i) organoaluminum oxy compounds include methylalumoxane, isobutylalumoxane, methylisobutylalumoxane, aluminum butylboronate, tetraisobutylmethylaluminum bispentafluorophenoxide, and the like. (Ii) As the Lewis acid, a compound represented by BR3 (wherein R is a phenyl group which may have a substituent such as a fluorine atom, a methyl group or a trifluoromethyl group or a fluorine atom) is used. For example, trifluoroborane, triphenylborane, tris (4-fluorophenyl) borane, tris (3,5-difluorophenyl) borane, tris (4-fluoromethylphenyl) borane, tris (pentafluorophenyl) borane , Tris (p-tolyl) borane, tris (o-tolyl) borane, tris (3,5-dimethylphenyl) borane and the like, and inorganic compounds such as magnesium chloride and aluminum oxide are also exemplified. (Iii) Examples of the ionic compound include trialkyl-substituted ammonium salts, N, N-dialkylanilinium salts, dialkylammonium salts, and triarylphosphonium salts. Specifically, examples of the trialkyl-substituted ammonium salt include triethylammonium tetra (phenyl) borate, tripropylammonium tetra (phenyl) borate, tri (n-butyl) ammonium tetra (phenyl) borate and the like. Examples of the dialkylammonium salt include di (1-propyl) ammonium tetrakis (pentafluorophenyl) borate and dicyclohexylammonium tetra (phenyl) borate. Further examples of the ionic compound include triphenylcarbenium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, ferrocenium tetra (pentafluorophenyl) borate, and the like. (Iv) Examples of clay minerals include montmorillonite, mica, teniolite, hectorite, modified products thereof treated with acid / base, and complexes with other inorganic oxides.

As a specific method for producing the propylene / ethylene block copolymer (A) of the present invention, propylene is supplied in the first stage, and the temperature is 50 to 150 ° C., preferably 50 in the presence of the polymerization catalyst. A propylene / ethylene random copolymer part containing 1.5 to 5.0% by mass of ethylene under the conditions of ~ 100 ° C and a partial pressure of propylene of 0.5 to 4.5 MPa, preferably 1.0 to 3.5 MPa. To manufacture. Subsequently, in the second stage, propylene and ethylene are supplied, and in the presence of the polymerization catalyst, the temperature is 50 to 150 ° C., preferably 50 to 100 ° C., and the partial pressures of propylene and ethylene are each 0.3 to 4. Propylene / ethylene copolymerization is carried out under conditions of 5 MPa, preferably 0.5 to 3.5 MPa, to produce a propylene / ethylene random copolymer part. At this time, the use ratio of ethylene and propylene in each stage is controlled by increasing or decreasing the amount of ethylene according to the target ethylene content. In the case of a metallocene catalyst, the ethylene weight ratio at the time of polymerization is generally higher than the ethylene content in the polymer. Further, the molecular weight and MFR at each stage are controlled by allowing a chain transfer agent, particularly preferably hydrogen, to coexist. The viscosity ratio of 40 ° C. and 110 ° C. TREF solubles of the composition described later has a close relationship with the molecular weight produced in the former and latter stages. Therefore, in order to obtain the desired composition, the target is obtained in the polymerization stage. It is possible to appropriately use a polymer produced according to the above.
The polymerization shown above may be batch-wise, continuous, or semi-batch, and the first stage polymerization may be in the gas phase or liquid phase, particularly in a propylene bulk liquid phase that does not use an inert solvent, or It is preferable to carry out in the gas phase, and the second stage polymerization is preferably carried out in the gas phase, and the residence time of each stage is 0.5 to 10 hours, preferably 1 to 5 hours. .

  In order to eliminate the stickiness of the powder particles of the propylene / ethylene block copolymer produced by the polymerization method and to impart fluidity, after the polymerization of the propylene-based polymerization portion in the first stage, the second stage Additives such as active hydrogen-containing compounds and oxygen-containing compounds before or during polymerization of the propylene / ethylene random copolymer portion in the catalyst to titanium atoms in the solid component of the catalyst or group 4 transition metals of the metallocene catalyst It is preferable to add in the range of 10 to 1000 times mol or 0.5 to 5 times mol for the organoaluminum compound present in the polymerization system. Here, as the active hydrogen-containing compound, for example, water, alcohols, phenols, aldehydes, carboxylic acids, acid amides, ammonia, amines, etc., oxygen-containing compounds such as acetone, ethyl ether, ethyl cellosolve, polyethylene glycol Etc.

2. Nucleator (B)
In the propylene / ethylene-based resin composition of the present invention, as the nucleating agent (B) used together with the propylene / ethylene block copolymer (A), various general known nucleating agents can be used.

  As the nucleating agent, an organic phosphate metal salt, an organic monocarboxylic acid metal salt, an organic dicarboxylic acid metal salt, a polymer nucleating agent, dibenzylidene sorbitol or a derivative thereof, a metal salt of diterpenic acid, or the like is used.

  Examples of the organic phosphate metal salt include sodium-2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate, sodium-2,2′-ethylidene-bis (4,6 -Di-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis (4,6-di-t-butylphenyl) phosphate, lithium-2,2'-ethylidene-bis (4,6 -Di-t-butylphenyl) phosphate, sodium-2,2'-ethylidene-bis (4-i-propyl-6-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis (4 -Methyl-6-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis (4-ethyl-6-t-butylphenyl) phosphate, nato Um-2,2′-butylidene-bis (4,6-di-methylphenyl) phosphate, sodium-2,2′-butylidene-bis (4,6-di-t-butylphenyl) phosphate, sodium 2,2′-t-octylmethylene-bis (4,6-di-methylphenyl) phosphate, sodium-2,2′-t-octylmethylene-bis (4,6-di-t-butylphenyl) phosphate Fate, calcium-bis- (2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate), magnesium-bis [2,2′-methylene-bis (4,6-di-) t-butylphenyl) phosphate), barium-bis [2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate), sodium-2,2′- Tylene-bis (4-methyl-6-tert-butylphenyl) phosphate, sodium-2,2′-methylene-bis (4-ethyl-6-tert-butylphenyl) phosphate, sodium-2,2′- Ethylidene-bis (4-m-butyl-6-tert-butylphenyl) phosphate, sodium-2,2'-methylene-bis (4,6-di-methylphenyl) phosphate, sodium-2,2'- Methylene-bis (4,6-di-ethylphenyl) phosphate, potassium-2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate, calcium-bis [2,2′- Ethylidene-bis (4,6-di-t-butylphenyl) phosphate), magnesium-bis [2,2′-ethylidene-bis (4,6-di-t-butyl) Ruphenyl) phosphate), barium-bis [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate), aluminum-tris [2,2′-methylene-bis (4,6 -Di-t-butylfell) phosphate], aluminum-tris [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate), and the like.

  Examples of the organic monocarboxylic acid metal salt include metal salts such as benzoic acid and allyl-substituted acetic acid. Specifically, benzoic acid, p-isopropylbenzoic acid, o-tertiary butylbenzoic acid, Examples thereof include pt-butylbenzoic acid, monophenylacetic acid, diphenylacetic acid, phenyldimethylacetic acid, adipic acid and their Li, Na, Mg, Ca, Ba, Al salts, and the like. Examples of the organic dicarboxylic acid metal salt include succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, phthalic acid, cyclohexanecarboxylic acid, norbornane dicarboxylic acid and their Li, Na, Mg, Ca, Ba, Al A salt etc. can be mentioned. Examples of the polymer nucleating agent include polyvinylcyclohexane, poly-3-methylbutene-1, and the like. Examples of the dibenzylidene sorbitol or derivatives thereof include 1,3,2,4-dibenzylidene sorbitol, 1,3-benzylidene-2,4-p-methylbenzylidene sorbitol, 1,3-benzylidene-2,4- p-ethylbenzylidene sorbitol, 1,3-p-methylbenzylidene-2,4-benzylidene sorbitol, 1,3-p-ethylbenzylidene-2,4-benzylidene sorbitol, 1,3-p-methylbenzylidene-2,4 -P-ethylbenzylidene sorbitol, 1,3-p-ethylbenzylidene-2,4-p-methylbenzylidene sorbitol, 1,3,2,4-di (p-methylbenzylidene) sorbitol, 1,3,2,4 -Di (p-ethylbenzylidene) sorbitol, 1,3,2,4-di (p- -Propylbenzylidene) sorbitol, 1,3,2,4-di (pi-propylbenzylidene) sorbitol, 1,3,2,4-di (pn-butylbenzylidene) sorbitol, 1,3,2, 4-di (ps-butylbenzylidene) sorbitol, 1,3,2,4-di (pt-butylbenzylidene) sorbitol, 1,3,2,4-di (p-methoxybenzylidene) sorbitol, , 3,2,4-di (p-ethoxybenzylidene) sorbitol, 1,3-benzylidene-2,4-p-chlorobenzylidenesorbitol, 1,3-p-chlorobenzylidene-2,4-benzylidenesorbitol, 3-p-chlorobenzylidene-2,4-p-methylbenzylidenesorbitol, 1,3-p-chlorobenzylidene-2,4-p-eth Benzylidene sorbitol, 1,3-p-methylbenzylidene-2,4-p-chlorobenzylidene sorbitol, 1,3-p-ethylbenzylidene-2,4-p-chlorobenzylidene sorbitol or 1,3,2,4-di (P-chlorobenzylidene) sorbitol and the like can be exemplified. In particular, 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di (p-methylbenzylidene) sorbitol or 1,3-p-chlorobenzylidene-2,4-p-methylbenzylidene sorbitol, Etc. are exemplified.

The metal salt of the diterpenic acid is a reaction product of the diterpenic acid and a predetermined metal compound such as a magnesium compound or an aluminum compound. Diterpenic acid is a rosin generally known as a natural resin obtained from a pine family, specifically, natural rosins such as gum rosin, tall oil rosin, wood rosin; disproportionated rosin, hydrogenated rosin, dehydrogenated Various rosins such as rosin, polymerized rosin, α, β-ethylenically unsaturated carboxylic acid-modified rosin; and purified products of the natural rosin and modified rosin are used as raw materials. Examples of the diterpenic acids include pimaric acid, sandaracopimalic acid, parastrinic acid, isopimaric acid, abietic acid, dehydroabietic acid, neoabietic acid, dihydropimaric acid, dihydroabietic acid, tetrahydroabietic acid, and the like.
Of these, preferred nucleating agents are organic phosphate metal salts and organic dicarboxylic acid metal salts, and more preferably sodium-2,2′-methylene-bis (4,6-di-t-butylphenyl). Phosphate metal salt having a substituted substituted aromatic group such as phosphate, sodium-2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate, or 2-cyclohexanedicarboxylic acid Examples thereof include alicyclic hydrocarbon dicarboxylic acid metal salts such as sodium acid, sodium 1,2-norbornanedicarboxylate, and magnesium 1,2-norbornanedicarboxylate. Examples of the metal salt include sodium, potassium, calcium, magnesium, aluminum salt and the like, and more preferred are group 1 metals such as sodium and potassium.

  The amount of the nucleating agent (B) used is 0.05 to 0.7 parts by weight, preferably 0.1 to 0.5 parts by weight, based on 100 parts by weight of the propylene / ethylene block copolymer (A). Part. If the amount of the nucleating agent (B) used is less than 0.05 parts by weight, the effect of improving the rigidity is insufficient, and if it exceeds 0.7 parts by weight, the effect is saturated and extra cost may be required. is there. In addition, you may use these nucleating agents in combination of 2 or more types.

3. Neutralizer (C)
The propylene / ethylene block copolymer composition of the present invention contains a neutralizing agent (C).

  As the neutralizing agent, various known metal soaps, hydrotalcites, aluminum calcium silicate, metal oxides and hydroxides, lithium aluminum composite hydroxide salts and the like can be used. In these, use of a metal soap and / or a hydrotalcite compound is preferable.

  Examples of the metal soap include metal salts of higher fatty acids or fatty acid oxyacids with metals such as magnesium, calcium, barium, zinc, aluminum, tin and lead. Examples of the higher fatty acid include chain monocarboxylic acids having 10 to 22 carbon atoms, and stearic acid and lauric acid are preferable. Examples of the fatty acid oxyacid include those having an alcoholic hydroxyl group in the side chain of the aliphatic carboxylic acid, and lactic acid, citric acid, hydroxystearic acid and the like are preferable. Preferable examples of the metal soap include magnesium stearate, calcium stearate, barium stearate, zinc stearate, aluminum stearate, calcium citrate, calcium lactate, 12 hydroxycalcium stearate, calcium stearyl lactate, calcium lauryl lactate and the like. .

The hydrotalcites are those containing no water-containing basic carbonate or crystal water such as magnesium, calcium, zinc, aluminum and bismuth, and include natural products and synthetic products. The natural product _include the _{Mg 6 Al 2 (OH) 16} CO 3 · 4H 2 O structures. Examples of the synthetic _{product, Mg 0.7 Al 0.3 (CO 3} ) 0.16 · 0.54H 2 O, Mg 4.5 Al 2 (OH) 12 CO 3 · 3.5H 2 O, Mg 4 _.2 Al ₂ (OH) _12.4 CO ₃ , Zn ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O, Ca ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O, Mg ₁₄ Bi ₂ (OH) _29.6 · 4.2H ₂ O and the like.
Examples of other neutralizing agents include metal oxides and hydroxides such as aluminum calcium silicate, zinc, aluminum, tin, and lead, and lithium aluminum composite hydroxide salts. Examples of the metal oxide and hydroxide include magnesium oxide, calcium oxide, zinc oxide, calcium hydroxide, aluminum hydroxide, and magnesium hydroxide.

The lithium aluminum composite hydroxide salt is generally a compound represented by the following general formula.
[LiAl ₂ (OH) ₆ ] ₂ X · mH ₂ O
(In the formula, X is CO ₃ , SO ₄ or HPO ₄ , and m is a number from 0 to _3. ) Examples of suitably used composite hydroxide salts of lithium and aluminum include [LiAl ₂ (OH) ₆ ] ₂ CO ₃ .1.6H ₂ O
_{[LiAl 2 (OH) 6]} 2 SO 4 · 1.2H 2 O
[LiAl ₂ (OH) ₆ ] ₂ HPO ₄ · 1.4H ₂ O
And so on. Such a composite hydroxide salt of lithium and aluminum effectively acts on the various nucleating agents described above, and increases the rigidity of the propylene / ethylene resin composition. The amount of the neutralizing agent (C) used is preferably 0.01 to 0.6 parts by weight, more preferably 0.02 to 0.5 parts per 100 parts by weight of the propylene / ethylene block copolymer (A). Part by weight, particularly preferably 0.04 to 0.15 part by weight. When the blending amount of the neutralizing agent (C) is less than 0.01 parts by weight, the oxidation heat resistance is inferior, and when it exceeds 0.6 parts by weight, the effect is saturated and the cost is increased. It is not preferable because it shifts to the mold surface and is contaminated, or shifts to the contents such as a container to impair the flavor.

4). Additional ingredients (optional ingredients)
In addition to the above component (A), component (B) and component (C), other additions may be added to the polypropylene resin composition used in the present invention, as long as the effects of the present invention are not significantly impaired. Ingredients (arbitrary ingredients) can be added.

  Such additional components (optional components) include ethylene / α-ethylene copolymers such as ethylene / propylene copolymer elastomers, ethylene / butene copolymer elastomers, ethylene / hexene copolymer elastomers, and ethylene / octene copolymer elastomers. Olefin copolymer elastomers, ethylene / propylene / ethylidene norbornene copolymer ethylene / α-olefin / diene terpolymer elastomers, elastomer components such as SEBS, SEPS and other styrene elastomers, phenolic and phosphorus Antioxidants, hindered amines, benzophenones, benzoates, benzotriazoles, weather resistance deterioration inhibitors, oleic acid amides, stearic acid amides, quinacridones, perylenes, phthalocyanines, titanium oxides, carbon bras Examples thereof include coloring materials such as lacquers, inorganic fillers such as talc, inorganic fillers and glass fibers, chemical foaming agents, and physical foaming agents.

[II] Propylene / ethylene resin composition Production of Propylene / Ethylene Resin Composition The propylene / ethylene resin composition of the present invention comprises the above component (A), component (B), optional component (C), and other optional components in an ordinary extruder, Manufactured by kneading at a preset temperature of 180 to 250 ° C. using a Banbury mixer, roll, Brabender plastograph, kneader, etc. Among them, it is manufactured using an extruder, particularly a twin screw extruder. Is preferred.

2. Physical Properties of Propylene / Ethylene Resin Composition The propylene / ethylene resin composition of the present invention satisfies the following characteristics (3), (4), (6) , and, if necessary, characteristics (1), ( 2) and (5) must be satisfied.

Characteristic (1) MFR
The melt flow rate MFRC of the propylene / ethylene resin composition of the present invention is measured in accordance with JIS K-7210-1995 (230 ° C., 21.18 N load), and is 5 to 100 g / 10 minutes, preferably 5 to 5 g. 80 g / 10 min. If the MFRC is less than the above range, the moldability tends to be insufficient, which is not preferable. On the other hand, if it becomes excessively high, the mechanical properties will be reduced.

Property (2) Total content of components having a weight average molecular weight Mw of 3,000 or less The total content of components having a weight average molecular weight Mw of 3,000 or less of the propylene / ethylene resin composition of the present invention is 1% by mass or less, Preferably it is 0.7 mass% or less.
A component having a weight average molecular weight of 3,000 or less becomes a volatile component at the time of molding, and causes bleed deposits on the mold, gas generation, poor appearance, odor deterioration, and the like. In addition, production is interrupted to remove deposits on the mold, and productivity is reduced. In particular, in the case of a high-cycle thin-walled injection container, gas generation due to volatile components generates heat due to rapid adiabatic compression of gas in the mold, causing burning trouble during molding.
The amount of the component having a weight average molecular weight of 3,000 or less can be controlled in various steps such as selection of a catalyst used during production of the propylene / ethylene block copolymer, polymerization method, composition production method and the like.
Here, the total content of the components having a weight average molecular weight Mw of 3,000 or less uses the absorbance at 2945 cm ⁻¹ obtained by FT-IR as a chromatogram, and the total elution amount of each elution component is 100%. Standardize so that It is a value obtained by integrating the portion where the weight average molecular weight is 3,000 or less from the total amount.

Property (3) tert-Butyl Alcohol Content The tert-butyl alcohol content of the propylene / ethylene resin composition of the present invention is 1 ppm or less, preferably 0.5 ppm or less. When the content of tert-butyl alcohol exceeds 1 ppm, the odor is deteriorated and it is avoided as a food container material. The reason why this compound remains is not clear, but it is generated by thermal oxidative degradation in the presence of oxygen during the decomposition of various additives and the production of a composition or container. Therefore, it is possible to control the molding method, the component (B), the component (C), the amount of the optional component, and various steps of selection. The effective means are the production of a composition in the absence of oxygen, melt molding, elimination of molding at a local high temperature, and the like. Here, the tert-butyl alcohol content is measured by the method described later.

Characteristics (4) Gas chromatograph (GC) / mass spectrometer (MS) with the measured C ₁ -C ₁₃ linear aliphatic Gas Chromatograph propylene-ethylene-based resin composition of the carboxylic acid content present invention (GC) / The total of the linear aliphatic carboxylic acid contents of C _{1 to} C ₁₃ measured with a mass spectrometer (MS) is preferably 1 ppm or less, more preferably 0.5 ppm or less.
In processing steps such as granulation, extrusion, and injection molding, an oxygen-containing compound such as carboxylic acid is generated due to resin deterioration due to an aerobic environment, which causes odor deterioration. In order to suppress this occurrence, the antioxidant is strengthened. However, when the amount is excessively mixed, the additive moves from the container to the contents, causing a change in odor and taste. In order to prevent this, a method of placing the molding machine in a nitrogen atmosphere, low-temperature molding, and the like have been proposed, but it is difficult to bring the molding machine into a complete nitrogen atmosphere, which increases the production efficiency. Further, in low temperature molding, the melt fluidity of the resin is remarkably lowered, causing appearance defects such as insufficient filling and uneven flow. When the resin composition of the present invention is used, in a container by injection molding, particularly a thin-walled container, the molding process temperature can be lowered because of good fluidity, and production can be continued in a high cycle. Such oxygen-containing product generation can be suppressed.

Here, the measurement of the tert-butanol and saturated linear aliphatic carboxylic acid contents measured by gas chromatograph (GC) / mass spectrometer (MS) is according to the following method.
(I) Outline of measurement and evaluation A composition or molded container is cut out to a predetermined weight and heated at 200 ° C., and volatile components generated therein are collected at −150 ° C., and then gas chromatograph (GC) / mass spectrometer (MS). To separate, detect and identify each volatile component.
The quantification of each volatile component is calculated with a value based on n-eicosane. Here, the target volatile component is a saturated linear aliphatic carboxylic acid having up to 13 carbon atoms and tert-butanol.

(Ii) Apparatus and measuring method (a) Heat eviction (dynamic headspace) apparatus: TDS-A manufactured by GUSTER
A sample of 0.3 ± 0.03 g is filled in a heat purge tube, and heated at 200 ° C. for 30 minutes and heat-extracted volatile components while a helium is vented at a flow rate of 20 ml / min. Here, the volatile components generated from the sample are collected by cooling the column tip used for the gas chromatograph to −150 ° C. with liquid nitrogen during heating.
Further, the collected components are desorbed by heating the collection column portion to 250 ° C. at a rate of 12 ° C./s and introduced into the separation column.
(B) Gas chromatograph (GC): HP6890 manufactured by Agilent
The column used was HP-INNO Wax (length: 60 m, inner diameter: 0.25 mm, liquid phase film thickness: 0.5 μm) manufactured by Agilent.
The temperature raising conditions of the column are 40 ° C. × 15 min to 5 ° C./min to 250 ° C. × 30 min, and the column flow rate is 1.4 ml / min.
(C) Mass spectrometer (MS): 5973 manufactured by Agilent
An electron impact (EI) method is used for ionization of the measurement component.

(Iii) Evaluation Method (a) From the chromatogram obtained by the measurement of 1-2, the peak area (A) of each component is calculated using the specific mass (m / z) ion shown below.
(A-1) Saturated linear aliphatic carboxylic acid: m / z 46 for formic acid, m / z 74 for propionic acid, m / z 60 for other substances
(A-2) tert-butanol: m / z 59
(B) A known amount of n-eicosane is measured under the same conditions as the sample, and the mass spectrometer sensitivity [total ion area of n-eicosane] / [injection weight of n-eicosane] (B) is determined.
(C) The n-eicosane equivalent generated concentration (C) of each component is calculated by dividing the area of each component of (a) by the sensitivity of (b) and the weight of the sample subjected to the measurement.
(D) Perform GC / MS measurement of the standard substance of each component, and calculate the intensity ratio (D) of [specific mass ions] / [total ions] of each component.
(E) The n-eicosane equivalent concentration using the specific mass ions of (c) is divided by the intensity ratio of (d) (C / D) to calculate the n-eicosane equivalent generation concentration (E) in the total ion intensity. To do.

Characteristics (5) Bending characteristic test: The bending characteristics of the resin composition were evaluated under the following conditions.
Standard number: JIS K-7171 (ISO178) compliant tester: Precision universal tester Autograph AG-20kNG (manufactured by Shimadzu Corporation)
Specimen sampling direction: Flow direction Specimen shape: Thickness 2.0 mm Width 25.0 mm Length 40.0 mm
Test piece preparation method: Injection molded flat plate was punched out to the above dimensions. Condition: Room temperature adjusted to 23 ° C and humidity 50%. Leave for 24 hours or longer Test room: Room temperature adjusted to 23 ° C and humidity 50% Number of temperature-controlled specimens: 5
Distance between fulcrums: 32.0mm
Test speed: 1.0 mm / min

Characteristic (6) Impact test: The resin composition was pulled at high speed and impact resistance was evaluated from the tensile behavior at that time. Evaluation conditions are shown below.
Tester: Servo pulsar high-speed impact tester EHF-2H-20L-Test specimen with a thermostatic chamber Sampling direction: Flow direction Test piece shape: Preparation method of JIS K7162-5A test piece: Injection molded flat plate is punched into the above shape Condition adjustment: Leave in a thermostatic chamber adjusted to room temperature 23 ° C. and humidity 50% for 24 hours or more Test chamber: Number of thermostatic test pieces adjusted to room temperature 23 ° C. and humidity 50%: 5
Tensile speed: 2m / sec
Measurement temperature: 23 ° C. and 0 ° C. (In the case of 0 ° C., set the temperature chamber to 0 ° C., set the sample and hold the temperature of the temperature chamber at the set temperature ± 1 ° C. for 10 minutes or more. Then measure)

[III] Injection molded body (container)
1. Production The injection molded container using the propylene / ethylene resin composition of the present invention is not particularly limited by the molding method, and a normal injection molding method, injection compression molding method or injection foam molding method can be used. It is.
For example, in a medium to small injection molding machine with a clamping force of 50 to 300 tons, a cup-shaped container having a diameter of 50 to 150 mm, a capacity of 30 to 500 cc, and an average wall thickness of 0.2 to 2 mm is formed at a molding temperature of 150 to 250 ° C. and an injection pressure. It can shape | mold on conditions, such as 20-200 MPa.

2. Physical Properties of Injection Molded Body The injection molded body (container) of the present invention has a total content of C _{1 to} C ₁₃ linear aliphatic carboxylic acids measured by gas chromatograph (GC) / mass spectrometer (MS) of 1 ppm. The following is preferable, and more preferably 0.5 ppm or less.
The C ₁ -C ₁₃ linear aliphatic carboxylic acid in the container is a cause of odor deterioration due to formation of oxygen-containing compounds such as carboxylic acid due to resin degradation due to an aerobic environment in processing steps such as extrusion and injection molding. It becomes. In order to suppress this occurrence, the antioxidant is strengthened. However, when the amount is excessively mixed, the additive moves from the container to the contents, causing a change in odor and taste. In order to prevent this, a method of placing the molding machine in a nitrogen atmosphere, low-temperature molding, and the like have been proposed, but it is difficult to bring the molding machine into a complete nitrogen atmosphere, which increases the production efficiency. Further, in low temperature molding, the melt fluidity of the resin is remarkably lowered, causing appearance defects such as insufficient filling and uneven flow. When the resin composition of the present invention is used, in a container by injection molding, particularly a thin-walled container, the molding process temperature can be lowered because of good fluidity, and production can be continued in a high cycle. Such oxygen-containing product generation can be suppressed.
Here, the measurement of linear aliphatic carboxylic acid content of the C ₁ -C ₁₃ measured by gas chromatography (GC) / mass spectrometer (MS), according to the method described above.
The tert-butanol content in the container is preferably 1 ppm or less, more preferably 0.5 ppm or less. When the content of tert-butanol exceeds 1 ppm, the odor of the container becomes worse and it is avoided as a food container. The reason why this compound remains is not clear, but it is generated by thermal oxidative degradation in the presence of oxygen during the decomposition of various additives and the production of a composition or container. Therefore, it is possible to control the molding method, the component (B), the component (C), the amount of the optional component, and various steps of selection. The effective means are the production of a composition in the absence of oxygen, melt molding, elimination of molding at a local high temperature, and the like. Here, the tert-butanol content is measured by the method described above.

3. Use of injection-molded product The propylene / ethylene resin composition of the present invention is a material capable of exhibiting the above performance, and can be used by molding into various molded products. Among them, desserts such as pudding and yogurt Containers containing food such as containers, mozuku containers and juice containers are preferred.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The physical property measurement methods and materials used are as follows.
1. Physical properties and evaluation method (1) Odor: Cut a cup-shaped container obtained by injection molding into several mm squares, and seal about 80 g in a clean Erlenmeyer flask with a capacity of 300 mL. After heating for 2 hours in the hot air circulating dryer, sensory evaluation was performed by a panel. The panelists were selected from 5 people who were selected by the preliminary test. The criteria for odor were the following 6 levels, expressed as the average of 5 people.
Class 0 Odorless Class 1 Class 2 that can be felt at last (I can understand the quality of the odor)
Level 3 Smells quite a lot (feels comfortable)
4th grade Strongly smelling 5th grade Smelling intensely (strong enough to be unbearable)

(2) Hue: After the side surface of a cup-shaped container obtained by injection molding was cut out and fixed flat, yellowness (YI) was determined using a photoelectric colorimeter in accordance with JIS-K7105.
(3) Drop impact: A low-temperature thermostatic bath adjusted to 5 ° C. by putting about 180 ml (90% of 200 ml) of water into a cup-shaped container obtained by injection molding and sealing the mouth with a wrap film for food packaging and rubber bands. For 2 hours. Thereafter, the containers were taken out one by one and quickly dropped, and the height at which the probability of destruction was 50% was determined. Containers that have been dropped are for one-time use and should not be used repeatedly.

(4) Appearance (strips): The outer surface of the cup-shaped container obtained by injection molding was evaluated by three steps by counting the total number of butts having a size of 0.2 mm or more by visual observation.
1 point: 0-5 pieces / container (almost inconspicuous)
2 points: 5-20 pieces / container (slightly noticeable)
3 points: 20 pieces / container (very conspicuous)

(5) Warpage: A box-shaped container obtained by injection molding is placed on a flat base so as to be on the opening. In this state, the degree of warpage of the side surface was visually observed and evaluated in three stages.
1 point: Warp is hardly noticeable 2 point: Warp is slightly noticeable 3 point: Warp is very noticeable

(6) Stackability: Cup-shaped containers obtained by injection molding were stacked one by one on a flat base plate, and the height when stacking 20 pieces was visually observed and evaluated in three stages. When stacking, without applying extra force, the center position of the newly stacked container and the stacked container were aligned and allowed to fall naturally vertically from the height of the mouth.
1 point: Lift is hardly noticeable 2 Point: Lift is slightly noticeable 3 Point: Lift is very noticeable

(7) Mold contamination: The resin composition is supplied to the Toshiba injection molding machine IS170 and filled up to about 50% of a sheet having a molding temperature of 230 ° C., a mold cooling water temperature of 40 ° C., a side of 120 mm, and a wall thickness of 2 mm. The injection primary pressure was adjusted to 10 to 50 MPa and the filling time was 2 seconds ± 0.4 seconds, and 100 shots were continuously formed. Thereafter, the degree of deposits on the mold surface was visually observed and evaluated in three stages.
1 point: almost inconspicuous 2 points: slightly conspicuous 3 points: very conspicuous

(8) Transparency (haze): The resin composition was evaluated under the following conditions.
Standard number: JIS K-7136 (ISO14782) JIS K-7361-1 compliant measuring machine: Haze meter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.)
Test piece thickness: 2 mm
Preparation of test pieces: Adjustment of injection molded flat plate state: Number of test pieces left for 24 hours in a temperature-controlled room adjusted to room temperature 23 ° C. and humidity 50% after molding: 3
The transparency (haze) is acceptable if it is 35% or less, and more preferably 30% or less.

2. Materials used (1) Propylene-ethylene copolymer The propylene-ethylene copolymers (respectively indicated as PP-1 to PP-12) obtained in the following Production Example 1-12 were used. The properties of each polymer are shown in Table 1.
Production Example 1 (Propylene-ethylene copolymer production method)
Preparation of prepolymerization catalyst (chemical treatment of silicate) To a glass separable flask equipped with a 10 liter stirring blade, 3.75 liters of distilled water and then 2.5 kg of concentrated sulfuric acid (96%) were slowly added. . At 50 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle size = 18 μm, particle size distribution = 10-40 μm) was dispersed, heated to 90 ° C., and maintained at that temperature for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake to reslurry it, and then filtered. This washing operation was performed until the pH of the washing solution (filtrate) exceeded 4.0. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 675 g.
(Drying of silicate) The chemically treated silicate was placed in a 1 L flask and heated using an oil bath heated to 200 ° C. under a nitrogen stream. After maintaining for 1 hour, the flow of nitrogen was stopped, and the inside of the flask was decompressed with a vacuum pump and dried under reduced pressure. Drying was continued for 2 hours while the temperature of the oil bath remained at 200 ° C. Thereafter, the flask was taken out from the oil bath and returned to normal pressure with nitrogen. Dry silicate was obtained.
(Preparation of catalyst) 20 g of dry silicate was introduced into a glass reactor equipped with a stirring blade having an inner volume of 1 liter, 116 ml of mixed heptane and 84 ml of a heptane solution of triethylaluminum (0.60 M) were added, and the mixture was stirred at room temperature. did. After 1 hour, the mixture was washed with mixed heptane to prepare a silicate slurry to 200 ml. Next, 0.96 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added to the silicate slurry prepared above and reacted at 25 ° C. for 1 hour. In parallel, 218 mg (0.3 mM) of [(r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] zirconium] and 87 ml of mixed heptane Then, 3.31 ml of a heptane solution of triisobutylaluminum (0.71 M) was added, and the mixture reacted at room temperature for 1 hour was added to the silicate slurry. After stirring for 1 hour, mixed heptane was added to prepare 500 ml. did.
(Preliminary polymerization / washing) Subsequently, the previously prepared silicate / metallocene complex slurry was introduced into a stirring autoclave having an internal volume of 1.0 liter that was sufficiently substituted with nitrogen. When the temperature was stabilized at 40 ° C., propylene was supplied at a rate of 10 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another hour.
After completion of the prepolymerization, the residual monomer was purged, stirring was stopped and the mixture was allowed to stand for about 10 minutes. Subsequently, 8.5 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added, followed by drying at 40 ° C. under reduced pressure. A prepolymerized catalyst containing 2.1 g of polypropylene per 1 g of catalyst was obtained.

Using this prepolymerized catalyst, a propylene-ethylene copolymer was produced according to the following procedure.
(First step)
The autoclave with an internal volume of 3 L having a stirring and temperature control device was sufficiently replaced with propylene, and then 2.8 ml (2.0 mmol) of triisobutylaluminum / n-heptane solution was added, followed by 26 g of ethylene, 120 ml of hydrogen, and then 750 g of liquid propylene. Was introduced and the temperature was raised to 60 ° C. to maintain the temperature. The above prepolymerized catalyst was slurried with n-heptane, and 20 mg of the catalyst (excluding the weight of the prepolymerized polymer) was injected to start polymerization. Polymerization was continued for 60 minutes while maintaining the temperature in the tank at 60 ° C. Thereafter, the residual monomer was purged to normal pressure and further completely replaced with purified nitrogen. When a part of the produced polymer was sampled and analyzed, the ethylene content was 3.1% by mass and the MFR was 26.5 g / 10 min.
(Second step)
The temperature was controlled at 40 ° C., 30 ml of hydrogen was introduced, and a proportional controller was used to adjust and introduce the ethylene gas composition with respect to the mixed gas of ethylene and propylene to 40 mol%. After the temperature was raised and the temperature reached 65 ° C. and the pressure became 1.8 MPa, the polymerization in the second step was started. Polymerization was continued for 30 minutes. Meanwhile, an ethylene / propylene mixed gas having a gas composition of 13 mol% was introduced so that the pressure did not fall below 1.8 MPa. Thereafter, 10 ml of ethanol was introduced to terminate the polymerization. Residual gas was purged. The recovered polymer was dried with a 60 ° C. vacuum dryer. The yield was 317 g and the catalyst efficiency was 16500 g / g. When a part of the produced polymer was sampled and analyzed, the ethylene content of the polymer produced in the second step was 16.2% by mass. The MFR of the entire propylene-ethylene copolymer was 26.4 g / 10 minutes.

Production Examples 2-11
Using the same catalyst as in Production Example 1, a propylene-ethylene copolymer was produced. The polymerization conditions and polymerization results are shown in Table 1.

Production Example 12
Propylene-ethylene copolymer was produced using a Ziegler-Natta catalyst.
(Production of solid component catalyst) 20 liters of dehydrated and deoxygenated n-heptane was introduced into a tank equipped with a stirrer having an internal volume of 50 liters purged with nitrogen, and then 10 moles of magnesium chloride and 20 moles of tetrabutoxytitanium were introduced. After reacting at 95 ° C. for 2 hours, the temperature was lowered to 40 ° C., 12,000 ml of methylhydropolysiloxane (viscosity 20 centistokes) was introduced, and the mixture was further reacted for 3 hours. The ingredients were washed with n-heptane.
Subsequently, 5 liters of dehydrated and deoxygenated n-heptane was introduced into the tank using the tank equipped with a stirrer, and then 3 mol of the solid component synthesized above was introduced in terms of magnesium atom. Next, 5 liters of silicon tetrachloride was mixed with 2.5 liters of n-heptane and introduced at 30 ° C. for 30 minutes. The temperature was raised to 70 ° C. and reacted for 3 hours. Then, the reaction solution was taken out, The resulting solid component was washed with n-heptane.
Subsequently, 2.5 liters of dehydrated and deoxygenated n-heptane was introduced into the tank using the tank equipped with a stirrer, 0.3 mol of phthalic acid chloride was mixed and introduced at 90 ° C. for 30 minutes, The reaction was carried out at 95 ° C. for 1 hour. After completion of the reaction, washing with n-heptane was performed. Next, 0.6 liter of silicon tetrachloride and 8 liter of n-heptane were introduced to obtain a solid component. This solid component contained 1.55 weight percent titanium.
Next, 8 liters of n-heptane, 400 g of the solid component obtained above, 0.27 mol of t-butyl-methyl-dimethoxysilane and 0.27 mol of vinyltrimethylsilane were introduced into the tank equipped with a stirrer substituted with nitrogen. And contacted at 30 ° C. for 1 hour. Next, the mixture was cooled to 15 ° C., 1.5 mol of triethylaluminum diluted in n-heptane was introduced over 15 minutes under 15 ° C., and after the introduction, the temperature was raised to 30 ° C. and reacted for 2 hours. Washing with heptane gave 390 g of a solid component catalyst.
The obtained solid component catalyst contained 1.35% by mass of titanium.

(Production of propylene / ethylene block copolymer)
(First step)
After fully replacing the 3 L autoclave with stirring and temperature control with propylene, 3.3 ml (4.0 mmol) of triethylaluminum / n-heptane solution was added, 1000 ml of hydrogen was introduced, followed by 750 g of liquid propylene. The temperature was raised to 65 ° C. and the temperature was maintained. The above solid polymerization catalyst was slurried with n-heptane, and 15 mg of the catalyst was injected to initiate polymerization. Polymerization was continued for 60 minutes while maintaining the temperature in the tank at 65 ° C. Thereafter, the residual monomer was purged to normal pressure and further completely replaced with purified nitrogen. When a part of the produced polymer was sampled and analyzed, the MFR was 25.5 g / 10 min.
(Second step)
The temperature was controlled at 40 ° C., 500 ml of hydrogen was introduced, and a proportional controller was used to adjust and introduce the ethylene gas composition to 30 mol% with respect to the mixed gas of ethylene and propylene. After the temperature was raised and the temperature reached 65 ° C. and the pressure became 1.8 MPa, the polymerization in the second step was started. Polymerization was continued for 30 minutes. Meanwhile, an ethylene / propylene mixed gas having a gas composition of 30 mol% was introduced so that the pressure did not fall below 1.8 MPa. Thereafter, 10 ml of ethanol was introduced to terminate the polymerization. Residual gas was purged. The recovered polymer was dried with a 60 ° C. vacuum dryer. The yield was 450 g and the catalyst efficiency was 31000 g / g. When a part of the produced polymer was sampled and analyzed, the ethylene content of the polymer produced in the second step was 16% by mass. The MFR of the entire propylene-ethylene copolymer was 29 g / 10 minutes.

(2) Nucleator (i) Nucleator (B-1): Organophosphate metal salt (Asahi Denka Kogyo; NA11)
(Ii) Nucleator (B-2): Metal salt of organic dicarboxylic acid (Milliken Chemical; HPN-68)
(Iii) Nucleator (B-3): Talc (Hayashi Kasei Co., Ltd .; Micro White # 5000S)
(Iv) Nucleator (B-4): Sorbitol (Mitsui Chemical Fine Co., Ltd .; NC-6)

Example 1
(1) Production of Resin Composition As propylene-ethylene copolymer (A), 0.15 nucleating agent (B-1) with respect to 100 parts by weight of powder (PP-1) obtained in Production Example 1. Parts by weight, 0.05 parts by weight of calcium stearate as neutralizing agent, pentaerythryl-tetrakis [3- (3,5-t-butyl-4-hydroxyphenyl) propionate] as a phenolic antioxidant (Ciba Specialty Chemicals) Manufactured; hereinafter abbreviated as RA1010) 0.02 part by weight, phosphorous antioxidant tris (2,4-di-t-butylphenyl) phosphate (manufactured by Ciba Specialty Chemicals); hereinafter abbreviated as RA168. ) 0.02 part by weight, 0.15 part by weight of oleic acid amide as a slip agent was added, and after nitrogen sealing with a super mixer, the mixture was mixed for 3 minutes. Thereafter, the powder was granulated at a cylinder temperature of 200 ° C., a screw rotation speed of 150 rpm, and an extrusion rate of 15 kg / h using a twin screw extruder TEM35 manufactured by Toshiba Machine Co., Ltd., and pellets of a propylene-ethylene resin composition Got.
Table 2 shows the physical properties of the obtained propylene-ethylene resin composition pellets.
(2) Manufacture of containers by injection molding The resin composition pellet sample obtained above is supplied to the Toshiba injection molding machine IS170 and molded so that it can be molded with an injection primary pressure of 80 Mpa and a filling time of 1 second ± 0.2 seconds. The temperature was adjusted at 170 ° C. to 280 ° C., and a cup-shaped container having a capacity of 200 ml and a wall thickness of 0.7 mm was molded at a mold cooling water temperature of 40 ° C. and a molding cycle of 15 seconds.
Similarly, the sheet was supplied to the Toshiba injection molding machine IS170, and a sheet having an injection primary pressure of 60 MPa, a molding temperature of 230 ° C., a mold cooling water temperature of 40 ° C., a molding cycle of 30 seconds and a side of 120 mm and a thickness of 2 mm was molded.
Also supplied to Toshiba injection molding machine IS170, injection primary pressure 60 MPa, secondary pressure 50 MPa, molding temperature 230 ° C., mold cooling water temperature 40 ° C., molding cycle 10 seconds, long side 110 mm, short side 70 mm, high A box-shaped molded product having a thickness of 45 mm and a thickness of 2 mm was molded.
The injection-molded cup-shaped container, box-shaped container and sheet were conditioned for 48 hours in a constant temperature and humidity state (temperature 23 ± 2 ° C., humidity 50 ± 5%), and various evaluations were performed. The results are shown in Table 2.

Example 2
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-2) obtained in Production Example 2 was used as the component (A).

Example 3
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-3) obtained in Production Example 3 was used as the component (A).

Example 4
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-4) obtained in Production Example 4 was used as the component (A).

Example 5
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-5) obtained in Production Example 5 was used as the component (A).

Examples 6-8
As the nucleating agent (component (B)), the nucleating agent (B-2), the nucleating agent (B-3), and the nucleating agent (B-4) were carried out except that the amounts shown in Table 2 were used. In the same manner as in Example 1, a resin composition and a container were obtained. The results are shown in Table 2.

Comparative Example 1
A resin composition and a container were obtained in the same manner as in Example 1 except that the nucleating agent (B-1) was not added. The results are shown in Table 3.

Comparative Example 2
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-6) obtained in Production Example 6 was used as the component (A).

Comparative Example 3
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-7) obtained in Production Example 7 was used as the component (A). The results are shown in Table 3.

Comparative Example 4
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-8) obtained in Production Example 8 was used as the component (A). The results are shown in Table 3.

Comparative Example 5
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-9) obtained in Production Example 9 was used as the component (A). The results are shown in Table 3.

Comparative Example 6
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-10) obtained in Production Example 10 was used as the component (A). The results are shown in Table 3.

Comparative Example 7
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-11) obtained in Production Example 11 was used as the component (A). The results are shown in Table 3.

Comparative Example 8
A resin composition and a container were obtained in the same manner as in Example 1 except that the propylene-ethylene copolymer (PP-12) obtained in Production Example 12 was used as the component (A). The results are shown in Table 3.

From the above results, in the examples, since the propylene-ethylene copolymer (A) of the present invention contains the nucleating agent (B), the resin composition and the container injection-molded using the resin composition are rigid. It can be seen that the impact balance is improved, the transparency is high, the whitening resistance is excellent, the odor and the like are not deteriorated, and the eluted components are small.
In contrast, in Comparative Example 1, since the nucleating agent (B) was not added, the Izod impact value, the drop impact, and the haze were deteriorated. In Comparative Example 2, since the propylene-ethylene copolymer (II) is not included, the Izod impact value and the stacking property are slightly poor. In Comparative Example 3, the ethylene content of the propylene-ethylene copolymer (I) is 0. For this reason, the appearance, warpage, stackability, and haze of the container are deteriorated.
In Comparative Examples 3 to 7, since either the ratio of the propylene-ethylene copolymer (I) (II) or the ethylene content falls outside the scope of the present invention, the Izod impact value, the appearance of the container, the warp, the stacking property. It can be seen that either haze is getting worse. Comparative Example 8 is a propylene-ethylene copolymer obtained by using a Ziegler-Natta catalyst. The content of Mw is 3000 or less, and the content of t-butanol is large. The value is getting worse.

Claims (3)

86 to 93% by mass of propylene / ethylene random copolymer (I) having an ethylene content of 1.5 to 5.0% by mass obtained by successive polymerization using a metallocene catalyst, and an ethylene content of 15 A propylene / ethylene-based resin composition comprising 7 to 14% by mass of propylene / ethylene random copolymer (II) which is about 35% by mass ,
For 100 parts by weight of the propylene-ethylene copolymer (A), an organic phosphate metal salt, an organic monocarboxylic acid metal salt, an organic dicarboxylic acid metal salt, a polymer nucleating agent, dibenzylidene sorbitol or a derivative thereof, or diterpenic acids It contains 0.05 to 0.15 parts by weight of one or more nucleating agents (B) selected from metal salts and 0.01 to 0.6 parts by weight of a neutralizing agent (C), and has a tert-butyl alcohol content. Is 0.5 ppm or less, and the total content of linear aliphatic carboxylic acids of C _{1 to} C ₁₃ measured with a gas chromatograph (GC) / mass spectrometer (MS) is 1 ppm or less and measured at 0 ° C. The propylene / ethylene resin composition is characterized by having an impact strength of 4.6 to 5.3 kJ / m ³ .   Propylene-ethylene copolymer (A) has an MFR (230 ° C., load 2.16 kg) of 5 to 100 g / 10 min and a total content of components having a weight average molecular weight (Mw) of 3,000 or less of 1 mass. The propylene / ethylene-based resin composition according to claim 1, wherein the propylene / ethylene-based resin composition is not more than%. A container obtained by injection molding the propylene / ethylene resin composition according to claim 1 or 2 .