JP2006045457A - Polypropylene-based resin composition, and stretchable film or stretchable sheet using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene-based resin composition which has improved impact resistance, cold resistance and stretchability without deteriorating transparency, and to provide a stretchable film or stretchable sheet using the same. <P>SOLUTION: This polypropylene-based resin composition comprising 50 to 99 wt.% of high stereo-specific propylene homopolymer and/or a propylene-α-olefin random copolymer having a MFR of 0.01 to 500 g/10 min and a melting point of 110 to 170°C obtained by DSC and 1 to 50 wt.% of (b) a propylenic polymer having a MFR of 0.01 to 1,000 g/10 min, not having an observed endothermic peak in a temperature range of 20 to 200°C obtained by DSC, and having a glass transition temperature of ≤-10°C obtained by a solid viscoelastisity measurement is characterized by having a single glass transition temperature of ≤0°C in a solid viscoelastisity measurement and a tensile breaking point strain L<SB>B</SB>[%] of ≥300 in a composition tensile test. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a propylene-based resin composition and a stretchable film or stretchable sheet using the same, and more specifically, a highly stereoregular propylene homopolymer and / or a propylene / α-olefin random copolymer component, and a specific A propylene-based resin composition having the following characteristics, superior in impact resistance and transparency, greatly improved in stretchability, and a stretchable film or stretchable sheet using the same .

Polypropylene is excellent in rigidity and strength, and has been widely used in various injection molding, blow, film, sheet molding methods. On the other hand, the material is brittle because of its high rigidity, and its impact resistance, cold resistance or stretchability is insufficient, and various improvements have been made to improve these. For example, it is a common practice to improve impact resistance by adding an elastomer component typified by an ethylene / α-olefin copolymer to a propylene-based resin. In addition, what is called a block copolymer or impact polypropylene obtained by continuously polymerizing a propylene component and an ethylene / propylene copolymer component is a material having a good balance between rigidity and impact resistance. provide. Furthermore, since the glass transition temperature of the ethylene / α-olefin copolymer is low, the cold resistance is also improved.
However, in these methods, since the ethylene / α-olefin copolymer component necessary for improving impact resistance is poorly compatible with the polypropylene component, a so-called phase separation structure is formed in the material. For this reason, the transparency deteriorated rather, and the stretchability was not sufficient.

On the other hand, a technique of obtaining a soft propylene homopolymer by reducing the stereoregularity of polypropylene and using this as a modifier for ordinary polypropylene resins is known (for example, Patent Documents 1 and 2). reference.). However, polypropylene with reduced stereoregularity cannot be expected to have improved cold resistance because the glass transition temperature is almost the same as that of ordinary high stereoregular polypropylene.
In contrast to this, it is known that a soft polypropylene homopolymer with a low glass transition temperature can be obtained by introducing structural defects called heterogeneous bonds into the propylene chain in the polymer main chain. (For example, refer to Patent Documents 3 to 5.)
Among them, Patent Document 4 discloses a polypropylene homopolymer having a specific heterogeneous bond ratio and stereoregularity ratio, and a technique of using the component as a low-temperature impact improving material. . However, in this technique, a thermoplastic resin having improved low-temperature impact containing this component only because of the low glass transition temperature of a polypropylene-based homopolymer having a specific heterogeneous bond ratio and a stereoregular ratio. The entire composition is widely included, and the composition of the composition necessary for the actual composition to obtain cold resistance is not specified. Also, no mention is made of techniques necessary to maintain or improve other mechanical properties of the material, such as transparency and stretchability. Therefore, it has been difficult to improve all of the impact resistance, cold resistance, and stretchability of the polypropylene-based resin without deteriorating the transparency in the conventional technique.
Japanese Patent Laid-Open No. 3-14851 JP 2003-41074 A JP-A-5-306304 JP 2001-192412 A JP 2003-292517 A

  The present invention is based on the present situation as described above, a polypropylene resin composition having improved impact resistance, cold resistance and stretchability without deteriorating transparency, and a stretchable film or stretchable sheet using the same. The purpose is to provide.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have greatly changed their mechanical properties due to differences in the phase separation structure and crystal structure of the composition. Is governed by the molecular weight and crystallinity of each resin component constituting the composition, or the thermodynamic interaction between the components, so at least these effects should not be considered when defining the composition. Therefore, based on the basic idea that a resin composition having desired characteristics cannot be obtained, the composition is composed of a composition of a polypropylene resin and a propylene homopolymer having specific characteristics including many different types of bonds. Specify the phase structure of the composition to improve not only the cold resistance of the product, but also transparency, impact resistance and stretchability, and to obtain such a structure The molecular weight of each component forming the crystalline, by limiting the scope of the heterologous binding, finds the necessary conditions for improving all of the above properties, and have completed the present invention.

That is, according to the first invention of the present invention, a highly stereoregular propylene homopolymer and / or a propylene / α-olefin random copolymer satisfying the following properties (a-1) to (a-2) ( a) polypropylene containing 1 to 50% by weight of propylene-based polymer (b) containing 50 to 99% by weight and 95% by weight or more of propylene satisfying the following characteristics (b-1) to (b-3) There is provided a polypropylene resin composition characterized by satisfying the following properties (i) and (ii).
Component (a):
(A-1) Melt flow rate (MFR) measured at 230 ° C. is in the range of 0.01 to 500 g / 10 min. (A-2) Melting point obtained by differential scanning calorimetry DSC is 110 to 170 ° C. Component (b):
(B-1) The melt flow rate (MFR) measured at 230 ° C. is in the range of 0.01 to 1000 g / 10 min. (B-2) In the differential scanning calorimetry DSC, the endotherm is between 20 and 200 ° C. No peak is observed (b-3) Resin composition having a glass transition temperature of −10 ° C. or lower obtained by solid viscoelasticity measurement:
(I) in the solid viscoelasticity measurement is the 0 ℃ having a glass transition temperature of the sole below (ii) Tensile Tensile break strain L _B in the test _[%] of the composition 300 or more

  In addition, according to the second invention of the present invention, there is provided a polypropylene resin composition characterized in that, in the first invention, the component (b) is a propylene homopolymer.

  According to the third invention of the present invention, in the first or second invention, (a-1) of component (a) has a melt flow rate (MFR) measured at 230 ° C. of 0.1 to 200 g / 10. And the component (b) (b-1) has a melt flow rate (MFR) measured at 230 ° C. of 0.1 to 500 g / 10 min. .

According to the fourth invention of the present invention, in any one of the first to third inventions, the components (a) and (b) are polymerized by a metallocene catalyst, and each of them is further represented by the following (a-3), A polypropylene resin composition characterized by satisfying the characteristics (b-4) is provided.
(A-3) Molecular weight distribution Mw / Mn measured by gel permeation chromatography (GPC) is in the range of 1 to 4 (b-4) Molecular weight distribution Mw measured by gel permeation chromatography (GPC) / Mn is in the range of 1-4

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the component (b) further satisfies the following property (b-5): Things are provided.
(B-5) The K value represented by the formula (1) obtained from ¹³ C-NMR measurement is in the range of 5 to 20, and the M value represented by the formula (2) is in the range of 10 to 70.

  According to the sixth aspect of the present invention, there is provided an extensible film or an extensible sheet comprising the polypropylene resin composition of any one of the first to fifth aspects.

  Since the polypropylene resin composition of the present invention is produced from a highly stereoregular polypropylene resin component (a) and a soft propylene polymer component (b) each having specific characteristics, it is more transparent than conventional ones. It is a composition having improved impact resistance, cold resistance, particularly stretchability.

  The polypropylene resin composition of the present invention is a composition containing (a) a highly stereoregular propylene homopolymer and / or a propylene / α-olefin random copolymer and (b) a propylene polymer. Hereinafter, the properties to be satisfied by the composition of the present invention and the constituent requirements of the components (a) and (b) constituting the composition will be specifically described in detail.

1. Component (1) Component (a) of Propylene Resin Composition
The component (a) used in the propylene resin composition of the present invention is a highly stereoregular propylene homopolymer and / or a propylene / α-olefin random copolymer. Here, as the α-olefin, ethylene or various olefins having 4 to 10 carbon atoms can be used, and among them, ethylene is preferable. However, unless it deviates from the main point of this invention, you may contain a trace amount of other comonomer.
Component (a) includes propylene homopolymer, propylene-α-olefin random copolymer as long as the following properties (a-1), (a-2) and (a-3) are satisfied as required. Any one of the polymers may be used alone, or a composition in which a plurality are selected from these groups and blended at an arbitrary blending ratio may be used. Since the main component of the MFR of the following characteristics (a-1) and (a-2) is the component (a), in order to ensure the rigidity, heat resistance and moldability of the polypropylene resin composition to some extent, It is an essential property.

Characteristic (a-1): MFR
The melt flow rate (MFR) measured at 230 ° C. of the component (a) used in the present invention needs to be in the range of 0.01 to 500 g / 10 minutes, preferably 0.1 to 200 g / 10 minutes. More preferably, it is 0.1-50 g / 10min. When the MFR is within this range, the obtained polypropylene resin composition is excellent in stretchability and can be suitably used particularly for film and sheet applications.
Here, MFR is a value measured according to JIS K7210 A method.

Characteristic (a-2) Melting Point The melting point obtained by differential scanning calorimetry DSC of the component (a) used in the present invention is in the range of 110 to 170 ° C, preferably in the range of 120 to 170 ° C. When the melting point is less than 110 ° C., the heat resistance is inferior, and those exceeding 170 ° C. are substantially difficult to produce.
Here, the melting point was determined by taking 5.0 mg of a sample by commercially available differential scanning calorimetry (DSC) measurement, holding the sample at 200 ° C. for 5 minutes, and then crystallizing to 20 ° C. at a rate of temperature decrease of 10 ° C./min. The melting peak temperature when melted at a heating rate of ° C./min.

Characteristic (a-3) Mw / Mn
As for molecular weight distribution Mw / Mn measured by the gel permeation chromatography (GPC) of the component (a) used by this invention, 1-4 are preferable, More preferably, it is 2.0-3.8. Those having an Mw of less than 1 cannot theoretically be produced, and those having an Mw of more than 4 means that molecules having a molecular weight that is much larger or smaller than that defined by the average molecular weight are mixed. This has an undesirable effect on the properties and stretchability.
In addition, Mw represents a weight average molecular weight and Mn represents a number average molecular weight.
Here, the conversion from the retention capacity obtained by the GPC measurement to the molecular weight is performed using a standard curve prepared in advance by standard polystyrene, and all the standard polystyrenes used are the following manufactured by Tosoh Corporation. Brands F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, and A1000 were used.
A calibration curve is created by injecting 0.2 mL of a solution dissolved in o-dichlorobenzene (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. The following numerical value is used for [η] = K × M ^α in the viscosity formula used for conversion to molecular weight.
PS: K = 1.38 × 10 ⁻⁴ α = 0.7
PP: K = 1.03 × 10 ⁻⁴ α = 0.78
The measurement conditions for GPC are as follows.
Equipment: GPC (ALC / GPC 150C) manufactured by WATERS
Detector: MIRAN 1A IR detector manufactured by FOXBORO (measurement wavelength: 3.42 μm)
Column: AD806M / S (3 pieces) manufactured by Showa Denko KK
Mobile phase solvent: o-dichlorobenzene Measurement temperature: 140 ° C
Flow rate: 1.0 ml / min Injection volume: 0.2 ml
Sample preparation: Prepare a 1 mg / mL solution using o-dichlorobenzene (containing 0.5 mg / mL BHT) and dissolve it at 140 ° C. for about 1 hour.
Mw and Mn are obtained from the chromatogram obtained by the measurement by a known method, and the molecular weight distribution defined by the ratio is calculated.

  The component (a) used in the present invention needs to have high stereoregularity from the viewpoint of heat resistance, and the component (a) may be a polymerization catalyst or the like as long as it satisfies these ranges. The production process is not particularly limited, and commercially available conventionally known polypropylene homopolymers and random copolymer resins can be used.

The component (a) used in the present invention is not particularly limited as long as it satisfies the above characteristics, and can be produced using various conventionally known catalysts. Since the product is characterized by excellent stretchability, it is preferable to use a metallocene catalyst that produces a small amount of low molecular weight components that adversely affect stretchability.
In particular, in order to obtain a polymer satisfying the characteristic (a-2), it is necessary to use a transition metal compound having a specific structure. Specifically, JP 2000-95791 A or JP 2003-292518 A. And a racemic azulenyl metallocene having a substituent at a specific position shown in Japanese Patent Publication. When polymerizing using a metallocene catalyst, together with the above transition metal compound, as a co-catalyst, a compound capable of converting the transition metal compound into a cation, such as an aluminum oxy compound (such as methylalumoxane), a clay mineral (montmorillonite) , Mica, etc.), Lewis acid (trispentafluorophenylborane, triethylaluminum, etc.) and ionic compounds (N, N-dimethylanilinium tetrakispentafluorophenylborate, etc.).

  In addition, when component (a) is produced, it is of course applied to solvent polymerization using a solvent, but it is also applicable to liquid phase solventless polymerization, gas phase polymerization, and melt polymerization that substantially do not use a solvent. Is done. It is also applicable to both continuous polymerization and batch polymerization. As the solvent in the solvent polymerization, a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, pentane, cyclohexane, benzene, toluene, or the like is used alone or as a mixture. The polymerization temperature is about -78 to 200 ° C, preferably -20 to 100 ° C, more preferably 50 to 80 ° C. Although there is no restriction | limiting in particular in the olefin pressure of a reaction system, Preferably it is the range of normal pressure-5MPa. In the polymerization, the molecular weight can be adjusted by a known means such as selection of temperature and pressure or introduction of hydrogen.

  The proportion of the component (a) in the polypropylene resin composition of the present invention is such that the component (a) is 50 to 99% by weight based on the entire composition in order to ensure that the component (a) is the main component. Yes, preferably 55 to 95% by weight. When the amount of component (a) is less than 50% by weight, the rigidity and heat resistance are poor, and when it exceeds 99% by weight, impact resistance, cold resistance and stretchability are insufficient.

(2) Component (b)
The propylene polymer (b) used in the propylene-based resin composition of the present invention is a propylene homopolymer or a copolymer of propylene and an α-olefin or other comonomer, containing 95% by weight or more of propylene. (B-1) to (b-3), and a soft propylene polymer satisfying the characteristics (b-4) to (b-5) as necessary. When the propylene content is less than 95% by weight, the compatibility of the component (b) with the component (a) is adversely affected, and as a result, the stretchability may be insufficient, preferably as the component (b) Uses a propylene homopolymer.

Characteristic (b-1) MFR
MFR measured at 230 degreeC of a component (b) needs to be the range of 0.01-1000 g / 10min, Preferably it is the range of 0.1-500g / 10min. When the MFR is within this range, the fluidity of the entire polypropylene resin composition obtained can be within the industrially preferable range.
Here, MFR is a value measured according to JIS K7210 A method.

Characteristic (b-2) Endothermic peak in DSC In the differential scanning calorimetry DSC measurement of component (b), it is necessary that no endothermic peak is observed between temperatures of 20 to 200 ° C. That is, the component (b) needs to be soft, that is, to have low crystallinity in order to improve the impact properties and stretchability of the entire composition, and has a temperature of 20 to 200 ° C. in DSC measurement. It is necessary that no melting point is observed in between.
Here, DSC measurement shall be performed similarly to the case of a component (a). When component (b) is so crystalline that the melting point is observed, the effect of improving impact properties and stretchability is reduced. The fact that the melting point is not observed is that, in the DSC measurement, when the endothermic curve is plotted against the temperature, there is almost no peak even if the peak is shown, and the endothermic amount is at most 5 mJ. / Mg or less.

Property (b-3) Glass Transition Temperature Component (b) is a component that imparts cold resistance to the composition, and for that purpose, it is necessary to define the glass transition temperature obtained by solid viscoelasticity measurement. The glass transition temperature obtained by solid viscoelasticity measurement is an index representing the temperature at which a material becomes brittle, and it can be said that a material having a lower glass transition temperature is less likely to be brittle at a low temperature. Therefore, the glass transition temperature of component (b) needs to be −10 ° C. or lower, preferably −15 ° C. or lower. Although there is no restriction | limiting in particular about the minimum of a glass transition temperature, The thing below -60 degreeC is difficult to manufacture normally. When the component (b) is polymerized, if a comonomer such as ethylene is copolymerized, the glass transition temperature can be lowered efficiently. As will be described later, the resin composition of the present invention undergoes phase separation. The comonomer content cannot be increased so much, and is preferably less than 5% by weight. In particular, it is preferable to use a propylene homopolymer.
Here, the solid viscoelasticity measurement is specifically performed by applying a sinusoidal strain of a specific frequency to a strip-shaped sample piece and detecting the generated stress. Here, the frequency is 1 Hz, and the measurement temperature is raised stepwise from −60 ° C. until the sample is melted and cannot be measured. Further, it is recommended that the magnitude of distortion is about 0.1 to 0.5%. From the obtained stress, the storage elastic modulus and the loss elastic modulus are obtained by a known method, and the loss tangent (= loss elastic modulus / storage elastic modulus) defined by the ratio thereof is plotted with respect to the temperature. A sharp peak is shown in the temperature region. Here, this peak temperature is defined as the glass transition temperature Tg (° C.).

Characteristic (b-4) Mw / Mn
As for molecular weight distribution Mw / Mn measured by the gel permeation chromatography (GPC) of the component (b) used by this invention, 1-4 are preferable, More preferably, it is 1.8-3.8. Those having an Mw of less than 1 cannot theoretically be produced, and those having an Mw of more than 4 means that molecules having a molecular weight that is much larger or smaller than that defined by the average molecular weight are mixed. This has an undesirable effect on the properties and stretchability.
In addition, the measuring method of Mw / Mn is the same method as the said component (a).

Characteristic (b-5) K value, M value As described above, the component (b) used in the present invention is preferably one having high compatibility with the polypropylene resin component (a). It is preferable to use a coalescence, but as an additional condition for controlling the glass transition temperature to −10 ° C. or lower with a propylene homopolymer, the melting point is not observed, and the K value obtained from ¹³ C-NMR measurement Is preferably in the range of 5 to 20, and the M value is preferably in the range of 10 to 70. If the K value is too low, the amount of heterogeneous bonds is too small, the glass transition temperature of component (b) cannot be lowered so much that cold resistance cannot be obtained. When it is too high, phase separation with the component (a) may occur, and a preferable range is 7 to 18. If the M value is too small, the stretchability may be inferior. If it is too large, sufficient impact properties and stretchability improvement effects cannot be obtained. The M value is an index for determining the degree of stereoregularity of the material. The higher this value is within an appropriate range, the more the compatibility between the component (a) and the component (b) is increased and the stretchability is improved. Therefore, the preferable range of the M value is 40 to 60.
Here, the K value and M value are calculated by ¹³ C-NMR measurement, and the K value quantifies structural disorder in the polymer chain as disclosed in JP-A No. 2001-192212. Therefore, it is represented by the following formula (1).
The peak intensities I (Sαα), I (βγ), and I (ασ) were in accordance with the method described in “Makromol. Chem., Rapid.

  The M value quantifies the stereoregularity in the polymer chain as shown in JP-A No. 2001-192412 and is represented by the following formula (2). Each peak intensity I (mmmm), I (mmr), I (rmmr), I (mrrm) was in accordance with the method described in “Makolemolecules” 1995, page 5403.

As long as the component (b) used in the present invention satisfies the above characteristics, the production method is not particularly limited, but a specific production method is a metallocene catalyst using a transition metal compound having a specific structure. Can be done. Specifically, a method using a racemic azulenyl metallocene having a substituent at a specific position described in JP-A-2003-292517 as a catalyst is preferable. Further, as a co-catalyst, an ionic compound or Lewis acid capable of converting the above transition metal compound into a cation, and a compound containing a fine particle carrier as an optional component can be used. About other matters, it can carry out similarly to manufacture of said component (a).
The component (b) is a propylene homopolymer as described above, or a copolymer of propylene and an α-olefin or other comonomer having a comonomer content of 5% by weight or less. Even if a propylene random copolymer having a comonomer content of 5% by weight or less is produced using a conventionally known Ziegler-Natta catalyst or a metallocene catalyst capable of producing a high melting point polypropylene for producing the component (a), The glass transition temperature cannot be lower than −10 ° C., and therefore it is difficult to impart cold resistance to the composition.

  The proportion of component (b) in the polypropylene resin composition of the present invention is 1 to 50% by weight, preferably 5 to 45% by weight, based on the entire composition. When the amount of the component (b) is less than 1% by weight, the impact resistance, cold resistance and stretchability are insufficient, and when it exceeds 50% by weight, the rigidity and heat resistance are poor.

(3) Additional components In the polypropylene resin composition of the present invention, conventionally known additives such as stabilizers, antioxidants, nucleating agents, UV absorbers, light, and the like are used as long as the gist of the present invention is not impaired. Addition of protective agent, metal deactivator, free radical scavenger, filler and reinforcing agent, compatibilizer, plasticizer, lubricant, emulsifier, fluorescent whitening agent, flame retardant, pigment, antistatic agent, foaming agent, etc. You may do it.

2. Production of Polypropylene Resin Composition The polypropylene resin composition of the present invention contains at least two components of component (a) and component (b). There is no method for producing two components by multi-stage polymerization, a method for producing different molecular weight components using a plurality of catalysts, a method for removing the solvent after mixing the two components in the presence of a solvent, an extruder or a brabender. For example, a melt kneading technique.

3. Properties of Polypropylene Resin Composition The polypropylene resin composition of the present invention is excellent not only in impact resistance and cold resistance but also in transparency and stretchability. Usually, when the composition exhibits a phase separation structure, the composition of the present invention is in the material because the transparency of the composition is inferior due to light scattering due to the difference in refractive index of each component. It is necessary to have no clear phase separation structure, and it is necessary to have the following characteristics (i) and (ii).

Characteristic (i) Glass transition temperature in solid viscoelasticity measurement The polypropylene resin composition of the present invention needs to have a single glass transition temperature at 0 ° C. or lower in solid viscoelasticity measurement.
It is a well-known fact that the degree of phase separation of a material can be distinguished by the appearance of solid viscoelastic peaks. Usually, in the case of a phase-separated material, since the glass transition temperatures of the respective components are different, a plurality of peaks of glass transition temperatures are observed. Conversely, when they are compatible, a single peak is observed between the glass transition temperatures of each component alone. The polypropylene resin composition of the present invention needs to be compatible to achieve improved physical properties in transparency and stretchability, and therefore the glass transition temperature needs to be independent, In order to impart cold resistance, the glass transition temperature needs to be 0 ° C. or lower. The lower limit of the glass transition temperature is necessarily the glass transition temperature of the component (b) alone.
Here, the definition of the glass transition temperature is the same as the definition in the component (b).

Characteristics (ii) Tensile strain at break L _B
Polypropylene resin composition of the present invention is characterized in that the stretchability is significantly improved, in a tensile test of the composition, the tensile strain at break L _{B [%]} 300 or more, preferably 400 Above, more preferably 500 or more.
Usually, soft components such as ethylene / α-olefin copolymer rubber (EPR), ethylene / α-olefin / diene copolymer rubber (EPDM), styrene are used to impart impact properties and stretchability to polypropylene resins. A method of adding ethylene / butylene / styrene block copolymer elastomer (SEBS) or the like is well known. When these components are used, a certain degree of improvement in stretchability, that is, an improvement in tensile strain at break, is achieved with a decrease in elastic modulus. By the way, when the composition obtained by such a conventional method is phase-separated, not only the deterioration of transparency, but also the occurrence of crazing due to peeling or stress concentration at the interface is inevitable. Naturally there is a limit to the improvement of sex. On the other hand, the polypropylene resin composition of the present invention is characterized by being compatible, and the relationship between the tensile modulus and the strain at break at tensile break is completely different from the composition of the phase separation system. In a tensile test of the composition, a material having a tensile breaking strain L _B [%] of 300 or more does not have a phase separation interface that is a factor that inhibits stretchability in the material, and is an extremely excellent stretchable material. It guarantees that there is.
Here, the tensile test was based on JIS K 7113, and was measured by punching a sheet of 2 mm thickness obtained by press molding into JIS K7162-5A type at a tensile rate of 25 mm / min at 23 ° C. To do.

4). Use of Polypropylene Resin Composition The polypropylene resin composition of the present invention can be suitably used for various molded products such as sheets, films, injection molded products, textile products, and packaging materials.
Since the polypropylene resin composition of the present invention is excellent in stretchability, it is particularly suitably used for sheets and films. Examples of film and sheet molding methods include air-cooled inflation molding, water-cooled inflation molding, non-stretching molding using a T die, uniaxial stretching molding, biaxial stretching molding, calendar molding, and press molding.
Moreover, when using as these films and sheets, the use as a layer in a multilayer structure is also possible.

In order to describe the present invention more specifically, examples and comparative examples will be described below. However, in order to clarify the present invention, preferred examples are described. Of course, the invention is not limited in any way by these examples.
The measuring methods of various physical properties obtained in the following Examples and Comparative Examples and the manufacturing method of the material resin used are as follows.

1. Evaluation Method (1) MFR: JIS K7210 Method A According to the condition M, the test temperature was 230 ° C., the nominal load was 2.16 kg, the die shape was 2.095 mm in diameter, and the length was 8.00 mm.
(2) Glass transition temperature: A sample cut from a 2 mm thick sheet into a strip shape of 10 mm width × 18 mm length × 2 mm thickness was used. The apparatus used was ARES manufactured by Rheometric Scientific. The frequency is 1 Hz. The measurement temperature was raised stepwise from −60 ° C., and the measurement was performed until the sample melted and became impossible to measure. The strain was performed in the range of 0.1 to 0.5%. From the obtained stress, a storage elastic modulus and a loss elastic modulus are obtained by a known method, and a loss tangent (= loss elastic modulus / storage elastic modulus) defined by the ratio thereof is plotted with respect to temperature, and a peak is shown. The temperature was taken as the glass transition temperature.
(3) Molecular weight distribution: determined according to the method described above.
(4) Tensile test (tensile modulus, tensile breaking strain L _B ): The sample was punched from a 2 mm thick sheet obtained by press molding under the following conditions, and the tensile test was performed under the following conditions. tensile modulus of elasticity was determined the tensile strain at break L _B.
Standard number: Compliant with JIS K-7162 (ISO 527-1) Testing machine: Precision universal testing machine Autograph AG-5kNG-With micro extensometer (manufactured by Shimadzu Corporation)
Shape of test piece: JIS K7162-5A type Preparation method of test piece: punching a sheet with a thickness of 2 mm into the above shape Condition: 24 h or longer in a temperature-controlled room adjusted to room temperature 23 ° C. and humidity 50% Test room: room temperature Number of temperature-controlled specimens controlled at 23 ° C. and 50% humidity: n = 5
Test speed: 1.0 mm / min (elongation up to 5 mm), 25.0 mm / min (elongation over 5 mm)
(5) K value, M value: Determined by measurement of ¹³ C-NMR. EX-270 manufactured by JEOL Ltd., measuring temperature was 130 ° C., and solvent was 1,2-dichlorobenzene and benzene-d6.
In addition, K value quantifies the disorder of the structure in a polymer chain, as shown by Unexamined-Japanese-Patent No. 2001-192212, and each peak intensity | strength I (S (alpha)), I ((beta) gamma), I ((alpha) (sigma)) is The method described in “Makromol. Chem., Rapid.
Moreover, M value quantifies the stereoregularity in a polymer chain, as shown by Unexamined-Japanese-Patent No. 2001-192412. Each peak intensity I (mmmm), I (mmr), I (rmmr), I (mrrm) was in accordance with the method described in “Makolemolecules” 1995, page 5403.
(6) Transparency (Haze): The transparency of an injection molded piece having a thickness of 2 mm was evaluated by haze. It measured based on JIS K-7136 (ISO 14782).
(7) Charpy impact strength: A notch was created on a 4 mm thick injection test piece with a notching machine, and Charpy impact strength was measured in accordance with JIS K-7111. The measurement conditions are as follows.
Capacity: 4J
Lifting angle: 150 °
Notch dimensions: Tip radius 0.25mm, notch depth 2.0mm, angle 45 °
Measurement temperature: 23 ° C
n number: 5

2. Material (Production Example 1)
(1) Complex synthesis According to the method disclosed in JP-A-2003-292518, dichloro {1,1'-dimethylsilylenebis [2-ethyl-4- (4-trimethylsilyl-3-methyl-phenyl) -4H-azurenyl] ]} Hafnium was synthesized.
(2) Chemical treatment of montmorillonite 1,700 g of pure water was added to a 5 L separable flask equipped with a stirring blade and a reflux device, and 500 g of 98% sulfuric acid was added dropwise. Further, 300 g of commercially available granulated montmorillonite (Mizusawa Chemical Co., Ltd., Benclay SL, average particle size: 19.5 μm) was added and stirred. Thereafter, the mixture was reacted at 90 ° C. for 2 hours. This slurry was washed with an apparatus in which an aspirator was connected to Nutsche and a suction bottle. A 900 mL aqueous solution of 325 g of lithium sulfate monohydrate was added to the recovered cake and reacted at 90 ° C. for 2 hours. This slurry was washed to pH> 4 with an apparatus in which an aspirator was connected to Nutsche and a suction bottle. The collected cake was dried at 120 ° C. overnight. As a result, 270 g of a chemically treated product was obtained.
(3) Organo-aluminum treatment of chemically treated montmorillonite 10.0 g of chemically treated montmorillonite obtained in (2) above was weighed into a 1 L flask, and 65 mL of heptane and 35.4 mL (25 mmol) of heptane solution of triisobutylaluminum were added. And stirred at room temperature for 1 hour. Thereafter, the remaining liquid was washed to 1/100 with heptane, and finally the amount of slurry was adjusted to 100 mL.
(4) Propylene polymerization using montmorillonite as cocatalyst Triisobutylaluminum (manufactured by Tosoh Akzo Co., Ltd.) (2.0 mmol, converted into Al atoms) was introduced into a 3 L stirring autoclave. On the other hand, the above complex (1.41 mg, 1.5 μmol) was diluted with toluene and introduced into the catalyst feeder, and the above slurry containing montmorillonite (50 mg) and triisobutylaluminum (7.5 μmol, converted to Al atoms) ) Was introduced and a contact time of 30 minutes was allowed. Thereafter, propylene (1500 mL) and hydrogen (90 mL) were introduced into the autoclave, and the catalyst in the catalyst feeder was introduced at room temperature. The temperature was raised to 70 degrees and polymerization was performed for 1 hour to obtain 78.3 g of polypropylene. The complex activity was 5.5 × 10 ⁴ g-PP / g-complex, and the catalyst activity was 1570 g-PP / g-solid. Polypropylene had an MFR of 155 g / 10 min, an Mw / Mn of 3.3, and a melting point of 160.4 ° C.

(Production Example 2)
(1) Chemical treatment of montmorillonite:
To a 3 L separable flask equipped with a stirring blade and a reflux apparatus, 1700 ml of ion-exchanged water was added, and 501 g of concentrated sulfuric acid was slowly added. The temperature of the aqueous solution was adjusted to 60 ° C., 300 g of commercially available granulated montmorillonite (Mizusawa Chemical Co., Ltd., Benclay SL, average particle size: 19 μm) was added, and the temperature was raised to 90 ° C. and reacted for 2 hours. Thereafter, 450 ml of ion exchange water was added and cooled to 50 ° C. The slurry was filtered under reduced pressure using a device in which an aspirator was connected to Nutsche and a suction bottle. The cake was collected, 2.0 L of pure water was added to reslurry, and filtration was performed. This operation was repeated three times, and the filtrate was washed so that the pH of the filtrate was 4 or more.
Furthermore, 1140 ml of ion exchange water and 324 g of lithium sulfate monohydrate were added to the same type separable flask used above and dissolved. Subsequently, the entire amount of the montmorillonite cake previously treated with sulfuric acid was added, and the temperature was raised to 90 ° C. and reacted for 2 hours. Thereafter, 700 ml of ion-exchanged water is added and cooled to 50 ° C. The slurry was filtered under reduced pressure using a device in which an aspirator was connected to Nutsche and a suction bottle. The cake was collected, 2.0 L of pure water was added to reslurry, and filtration was performed. This operation was repeated three times. The collected cake was pre-dried at 120 ° C. for 12 hours under a nitrogen stream. As a result, 235 g of a chemically treated product was obtained. Furthermore, in order to remove moisture contained in a small amount, drying was performed at 200 ° C. for 2 hours under reduced pressure.
(2) Preparation of prepolymerized catalyst 10.0 g of the chemically treated montmorillonite obtained above was weighed into a 1 L flask, and 64.6 ml of heptane and 35.4 ml (25 mmol) of a heptane solution of triisobutylaluminum were added at room temperature. Stir for 1 hour. Thereafter, it was washed with heptane, and finally the amount of slurry was adjusted to 100 ml.
0.43 ml (0.304 mmol) of a triisobutylaluminum heptane solution was added to the triisobutylaluminum-treated montmorillonite heptane slurry prepared above and stirred at room temperature for 10 minutes. In another flask (volume: 200 mL), the dichloro [1,1′-dimethylsilylenebis {2-ethyl-4- (3-methyl-4-trimethylsilylphenyl) -4-hydroazurenyl] of Production Example 1 (1) above was prepared. }] Toluene (30 ml) was added to the hafnium racemate (0.150 mmol), and the mixture was added to the 1 L flask and stirred at room temperature for 60 minutes. Next, 370 ml of heptane was further added to the mixed reaction product of montmorillonite and metallocene complex, and the mixture was introduced into a stirring autoclave having an internal volume of 1 liter. When the temperature in the autoclave was stabilized at 40 ° C., the above prepared metallocene complex solution was added, and then propylene was supplied at a constant rate of 238 mmol / hour (10 g / hour) for 120 minutes. After the completion of the propylene supply, the temperature was raised to 50 ° C. and maintained for 2 hours, after which the remaining gas was purged and the prepolymerized catalyst slurry was recovered from the autoclave. The recovered prepolymerized catalyst slurry was allowed to stand, and the supernatant liquid was extracted. To the remaining slurry, 8.5 ml (6.0 mmol) of a triisobutylaluminum heptane solution was added at room temperature, stirred at room temperature for 10 minutes, and then dried under reduced pressure to recover 33.3 g of a solid catalyst. The prepolymerization ratio (a value obtained by dividing the amount of the prepolymerized polymer by the amount of the solid catalyst) was 2.29.
(3) Propylene polymerization using montmorillonite as a cocatalyst After the inside of the polymerization tank (autoclave with a stirrer having an internal volume of 3 liters) was sufficiently substituted with propylene, 2.76 ml (2.02 mmol) of a triisobutylaluminum heptane solution was added, 90 ml of hydrogen and then 1500 ml of liquid propylene were introduced, and the temperature was raised to 65 ° C. Polymerization was initiated by injecting 40 mg of the previously prepared prepolymerized catalyst as a solid catalyst (amount of net solid catalyst excluding prepolymerized polymer). The temperature in the tank was maintained at 65 ° C., and polymerization was carried out for 1 hour. The residual monomer was purged to terminate the polymerization, and the recovered polymer was dried at 90 ° C. under a nitrogen stream for 1 hour.
As a result, the obtained propylene polymer was 259 g, and the catalytic activity was 6480 g-PP / g-solid. Polypropylene had an MFR of 3.5 g / 10 min and a melting point of 159.1 ° C.

(Production Example 3)
(1) Complex synthesis Dichlorodimethylsilylenebis (2-methyl-4,8-diphenyl-8-n-butyl-8H-azurenyl) hafnium was synthesized according to the method disclosed in Japanese Patent Application Laid-Open No. 2003-292517.
(2) Polymerization of propylene using methylalumoxane as a cocatalyst 8 mmol (in terms of Al atom) of methylalumoxane (“MMAO” manufactured by Tosoh Akzo Co., Ltd.) was introduced into a 3 L stirred autoclave. On the other hand, the above racemic / meso mixture (racemic / meso = 5/1, 1.44 mg) was diluted with toluene and introduced into the catalyst feeder. Then, after introducing 1500 mL of propylene into the autoclave, the rupturable plate was cut at room temperature, heated to 70 ° C., and subjected to a polymerization operation for 1 hour to obtain 60 g of polypropylene. The complex activity was 4.2 × 10 ⁵ (g-polymer / g-complex). Tm of polypropylene was not observed, MFR was 50 g / 10 min, Mw / Mn was 3.0, K value was 10, M value was 56, and Tg was −18 ° C.

(Production Example 4)
(1) Complex synthesis Dichlorodimethylsilylenebis (2-methyl-4-phenyl-8-n-butyl-8H-azurenyl) hafnium was synthesized according to the method disclosed in Japanese Patent Application Laid-Open No. 2003-292517.
(2) Polymerization of propylene using methylalumoxane as a cocatalyst 8 mmol (in terms of Al atom) of methylalumoxane (“MMAO” manufactured by Tosoh Akzo Co., Ltd.) was introduced into a 3 L stirred autoclave. On the other hand, the above racemate (1.37 mg) was diluted with toluene and introduced into the catalyst feeder and pre-contacted for 30 minutes. Then, after introducing 1500 mL of propylene into the autoclave, the catalyst in the catalyst feeder was introduced. The temperature was raised to 70 ° C. and a polymerization operation was carried out for 1 hour to obtain 64 g of polypropylene. The complex activity was 4.7 × 10 ⁴ (g-polymer / g-complex). The MFR was 210 g / 10 min, the Mw / Mn was 2.9, the K value was 16, the M value was 17, and the Tg was −20 ° C.
The above production example was repeated several times to obtain the required amount of sample.

Example 1
As the component (a) and the component (b), the polymers obtained in Production Example 1 and Production Example 3 were used, respectively, and dry-blended at the ratios shown in Table 1, and the additives were further mixed and sufficiently mixed. . As additives, antioxidants: tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane 500 ppm, tris (2,4-di-t-butyl) Phenyl) phosphite 500 ppm, neutralizing agent: calcium stearate 500 ppm was added.
The sample in which the additive was blended was granulated under the following conditions using a KZW-15-45-MG twin screw extruder manufactured by Technobel, and used as a pellet for injection molding.
Screw: 15mm aperture, L / D = 45
Extruder set temperature: (from below the hopper) 40, 80, 160, 200, 220, 220 (die) [° C.]
Screw rotation speed: 400rpm
Discharge amount: Adjusted to 1.5 kg / h with a screw feeder Die: 3 mm diameter strand die, 2 holes The obtained raw material pellets were press-molded using a commercially available compression molding machine, and used as test pieces for evaluating physical properties . The press molding was performed under conditions of a preheating temperature of 230 ° C. for a preheating time of 7 minutes, a pressurization of 50 kg / cm ² at 230 ° C. for 3 minutes, and a water cooling of 100 kg / cm ^{2 for} 3 minutes.
Moreover, the obtained raw material pellet was injection-molded on condition of the following, and the flat test piece for Charpy impact strength and Haze measurement was obtained. Various physical properties were measured using the obtained test pieces. The results are shown in Table 1.
Standard number: JIS K-7152 (ISO 294-1)
Molding machine: TU-15 injection molding machine manufactured by Toyo Machine Metal Co., Ltd. Molding machine set temperature: 80, 160, 200, 200, 200 ° C. (from under the hopper)
Mold temperature: 40 ℃
Mold shape: flat plate (thickness 4mm, width 10mm, length 80mm and thickness 2mm, width 30mm, length 90mm)

(Examples 2 to 5)
A composition was obtained in the same manner as in Example 1 except that the resin used as component (a) and component (b) and the blending ratio were changed as shown in Table 1, and the physical properties were measured. The results are shown in Table 1.

(Comparative Examples 1 and 2)
A composition shown in Table 1 was used as the component (a), and a composition was obtained in the same manner as in Example 1 except that the component (b) was not used. The results are shown in Table 1.

(Comparative Example 3)
A composition was obtained in the same manner as in Example 1 except that ethylene-propylene rubber (EP02P manufactured by JSR Corporation) was used as the component (b). The results of physical property measurement are shown in Table 1.
In Comparative Example 3, when tan δ was plotted against temperature, two peaks were observed at a temperature of 10 ° C. or lower, that is, the glass transition temperature was two peaks, and the phase separation system was obtained. In addition, the tensile strain at break is small, and the effect of improving stretchability is not sufficient. Moreover, the haze was also bad.

(Comparative Example 4)
A composition was obtained in the same manner as in Example 1 except that an ethylene-octene copolymer (EG8842 manufactured by DuPont Dow Elastomer Japan Co., Ltd.) was used as the component (b). The results of physical property measurement are shown in Table 1.
In Comparative Example 4, when tan δ was plotted against temperature, two peaks were observed at a temperature of 10 ° C. or lower, that is, the glass transition temperature was two peaks, and the phase separation system was obtained. In addition, the tensile strain at break is small, and the effect of improving stretchability is not sufficient. The haze is also bad.

(Comparative Example 5)
A composition was obtained in the same manner as in Example 5 except that an ethylene-octene copolymer (EG8842 manufactured by DuPont Dow Elastomer Japan Co., Ltd.) was used as the component (b). The results of physical property measurement are shown in Table 1.
In Comparative Example 5, when tan δ was plotted against temperature, two peaks were observed at a temperature of 10 ° C. or lower, that is, the glass transition temperature was two peaks, which was a phase separation system. Moreover, although the tensile strain at break is high, the haze is poor.

  Since the polypropylene resin composition of the present invention is a composition having improved transparency, impact resistance, cold resistance, and particularly stretchability, various moldings such as sheets, films, injection molded articles, textile products, and packaging materials. It can be used suitably for goods.

Claims (6)

High stereoregular propylene homopolymer and / or propylene / α-olefin random copolymer (a) satisfying the following properties (a-1) to (a-2) (50) to 99% by weight, and (b- A polypropylene resin composition containing 1 to 50% by weight of a propylene polymer (b) containing 95% by weight or more of propylene satisfying the characteristics of 1) to (b-3), wherein the following (i) and A polypropylene resin composition satisfying the characteristic (ii).
Component (a):
(A-1) Melt flow rate (MFR) measured at 230 ° C. is in the range of 0.01 to 500 g / 10 min. (A-2) Melting point obtained by differential scanning calorimetry DSC is 110 to 170 ° C. .
Component (b):
(B-1) The melt flow rate (MFR) measured at 230 ° C. is in the range of 0.01 to 1000 g / 10 min. (B-2) In the differential scanning calorimetry DSC, the endotherm is between 20 and 200 ° C. No peak is observed (b-3) Resin composition having a glass transition temperature of −10 ° C. or lower obtained by solid viscoelasticity measurement:
(I) in the solid viscoelasticity measurement is the 0 ℃ having a glass transition temperature of the sole below (ii) Tensile Tensile break strain L _B in the test _[%] of the composition 300 or more   2. The polypropylene resin composition according to claim 1, wherein the component (b) is a propylene homopolymer.   Component (a) (a-1) Melt flow rate (MFR) measured at 230 ° C. is 0.1 to 200 g / 10 min, Component (b) (b-1) Melt flow measured at 230 ° C. The polypropylene resin composition according to claim 1, wherein the rate (MFR) is 0.1 to 500 g / 10 minutes. The components (a) and (b) are polymerized by a metallocene catalyst, and each further satisfies the following properties (a-3) and (b-4): The polypropylene resin composition described in 1.
(A-3) Molecular weight distribution Mw / Mn measured by gel permeation chromatography (GPC) is in the range of 1 to 4 (b-4) Molecular weight distribution Mw measured by gel permeation chromatography (GPC) / Mn is in the range of 1-4 The polypropylene resin composition according to any one of claims 1 to 4, wherein the component (b) further satisfies the following property (b-5).
(B-5) The K value represented by the formula (1) obtained from ¹³ C-NMR measurement is in the range of 5 to 20, and the M value represented by the formula (2) is in the range of 10 to 70.

  A stretchable film or a stretchable sheet comprising the polypropylene resin composition according to any one of claims 1 to 5.