JPH11269328A - Propylene resin composition and oriented film made thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition exhibiting excellent low-temperature shrinkability, transparency, gloss, rigidity, antiblocking property, pin-hole resistance in shrinking, etc., and useful for shrink package film by compounding a specific propylene resin with a specific antiblocking agent. SOLUTION: This composition is produced by compounding (A) 100 pts.wt. of a random copolymer of a 2C or 4-20C α-olefin (Z) and propylene, having a melt flow rate of 1-20 g/10 min, a memory effect of 0.9-1.4, a main melting peak temperature (TP) of 100-145 deg.C and melt-finish temperature of <=(8+[TP]) deg.C determined by a differential scanning calorimeter, o-chlorobenzene extraction amount of <=2 wt.%, <=5 wt.% and <=20 wt.% at <=40 deg.C, <=50 deg.C and <=60 deg.C in temperature-increasing dissolution fractionation, respectively and containing the component Z in an amount [E mol%] falling within the range of formula 1 and formula II with (B) 0.01-1 pt.wt. of an antiblocking agent having an average particle diameter of <=10 μm (e.g. spherical silica or spherical fine particle of magnesium silicate).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a propylene-based resin composition and a film using the same. More specifically, it has high shrinkage at low temperature, excellent transparency, gloss, rigidity, and blocking resistance, and also has excellent hot-slip properties during packaging, and excellent pinhole resistance during shrink packaging after fusing and sealing. The present invention relates to a propylene-based resin composition suitable for producing a heat-shrinkable packaging film with little decrease in transparency and gloss afterwards, and a stretched film using the same.

[0002]

2. Description of the Related Art Conventionally, a polypropylene film has been widely used as a shrink film having shrinkability in a biaxial direction for packaging of instant food containers such as ramen and sake packs, but is not always satisfactory in quality. For example, in order to obtain a film with excellent low-temperature shrinkability, a method of increasing the ethylene content of the propylene / ethylene random copolymer, lowering the melting peak temperature, and improving shrinkage at low temperatures has been proposed. Blocking resistance, rigidity, hot-slip property during packaging (slip property in the process of folding a film in a shrink wrapping machine onto a tube and packaging a container (heated by a fusing seal heater), or immediately after passing through a shrink tunnel , Shrink wrapped containers (slip property in boxing process),
There is a problem that pinhole resistance at the time of shrink wrapping after fusing and sealing, and transparency and gloss after shrinkage are reduced.

[0003]

SUMMARY OF THE INVENTION In view of the above problems, the present inventors have high shrinkage at low temperatures, and have transparency, gloss,
A propylene-based resin composition that is excellent in rigidity, blocking resistance, hot-slip property during packaging, pinhole resistance during shrink packaging after fusing and sealing, and has little decrease in transparency and gloss after shrinking, and It is to provide a stretched film used.

[0004]

Means for Solving the Problems As a result of diligent studies to solve the above problems, it has been found that the present invention can be achieved by blending a specific propylene resin with a specific antiblocking agent. The present invention has been completed and the present invention has been completed. That is, the propylene-based resin composition of the present invention has an average particle size of 10 μm in 100 parts by weight of a propylene / α-olefin random copolymer containing propylene as a main component satisfying the following physical properties (1) to (6).
It is characterized by comprising 0.01 to 1.0 parts by weight of the following antiblocking agent. Physical properties (1): Melt flow rate (MFR) is 1.0
２０20 g / 10 min. Physical properties (2): Memory effect (ME) is 0.9-
Physical property (3): The temperature [TP] of the main melting peak determined by a differential scanning calorimeter (DSC) is 100 to 145 ° C. Physical property (4): Differential scanning calorimeter The melting end temperature [TE] (° C.) determined by (DSC) is [TE] − [TP] ≦ 8
Physical properties (5): a random copolymer obtained by combining an α-olefin component having 2 or 4 to 20 carbon atoms with propylene, wherein at least one α-olefin component is contained, and an α-olefin component is contained. The amount [E] (mol%) is within the range represented by the following formulas [I] and [II]; (140− [TP]) / 10.2 ≦ [E] ≦ (160− [TP] ] /2.6 Formula [I] 0 <[E] ≦ 23 Formula [II] Physical properties (6): Measurement by temperature-rise elution fractionation (TREF) using orthodichlorobenzene as a solvent At 40 ° C
The extraction amount extracted below is 2.0% by weight or less, the extraction amount extracted at 50 ° C or less is 5.0% by weight or less, and 60 ° C
The extraction amount extracted below is 20% by weight or less,

Further, a stretched film according to another invention of the present invention is used in 100 parts by weight of a propylene / α-olefin random copolymer containing propylene as a main component satisfying the following physical properties (1) to (6). After forming a film using a propylene-based resin composition containing 0.01 to 1.0 parts by weight of an anti-blocking agent having an average particle size of 10 μm or less, the film is stretched in at least one direction. It is assumed that. Physical properties (1): Melt flow rate (MFR) is 1.0
２０20 g / 10 min. Physical properties (2): Memory effect (ME) is 0.9-
Physical property (3): The temperature [TP] of the main melting peak determined by a differential scanning calorimeter (DSC) is 100 to 145 ° C. Physical property (4): Differential scanning calorimeter The melting end temperature [TE] (° C.) determined by (DSC) is [TE] − [TP] ≦ 8
Physical properties (5): a random copolymer obtained by combining an α-olefin component having 2 or 4 to 20 carbon atoms with propylene, wherein at least one α-olefin component is contained, and an α-olefin component is contained. The amount [E] (mol%) is within the range represented by the following formulas [I] and [II]; (140− [TP]) / 10.2 ≦ [E] ≦ (160− [TP] ] /2.6 Formula [I] 0 <[E] ≦ 23 Formula [II] Physical properties (6): Measurement by temperature-rise elution fractionation (TREF) using orthodichlorobenzene as a solvent At 40 ° C
The extraction amount extracted below is 2.0% by weight or less, the extraction amount extracted at 50 ° C or less is 5.0% by weight or less, and 60 ° C
The amount extracted below is 20.0% by weight or less;

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [I] Propylene resin composition (1) Constituent (A) Propylene / α-olefin random copolymer Propylene containing propylene as a main component used in the propylene resin composition of the present invention. The α-olefin random copolymer is composed of propylene as a main component and 2 carbon atoms as a subcomponent.
Or 4 to 20, preferably 4 to 8, α-olefin, or a random copolymer of ethylene and 4 to 20, preferably 4 to 8 α-olefin, having the following physical properties (1) To (3) are satisfied.

[0007] The object of physical properties (1): a melt flow rate (MFR: Melt
Flow Rate) is in the range of 1.0 to 20 g / 10 min, preferably 1.0 to 10 g / 10 min.
If the melt flow rate is lower than the lower limit of the above range,
If the extrudability of the film is poor, and if it is higher than the upper limit, the impact strength of the film is significantly reduced. Physical properties (2): Memory effect (ME: Memor)
y Effect) is in the range of 0.9 to 1.4. When the memory effect is lower than the lower limit of the above range, the extrusion moldability becomes poor, and when the memory effect is higher than the upper limit, the transparency of the film decreases. Physical properties (3): Differential scanning calorimeter (DSC: Diffe
rental scanning calorime
ter), the melting peak temperature [TP] is 100 to
145 ° C., preferably 110-140 ° C. When the main melting peak temperature determined by a differential scanning calorimeter is lower than the lower limit of the above range, blocking resistance is poor and rigidity is reduced. On the other hand, when it is higher than the upper limit of the above range, the impact resistance decreases.

Physical properties (4): The melting end temperature [TE] (° C.) determined by a differential scanning calorimeter is [TE] − [TP] ≦
8 is within the range. If the above [TE]-[TP] exceeds 8 ° C., complete sealing properties cannot be obtained, and pinhole resistance decreases. Physical property (5): The content [E] (mol%) of the α-olefin component used as a comonomer is represented by the following formula [I]
Within the range represented by (140− [TP]) / 10.2 ≦ [E] ≦ (160− [TP]) / 2.6 [I] The melting peak temperature [TP] obtained with a differential scanning calorimeter is Outside the range represented by the above formula [I], the blocking resistance is poor. Further, the content of the α-olefin component [E] (m
ol%) is within the range represented by the following formula [II]. 0 <[E] ≦ 23, preferably 0 <[E] ≦ 18, particularly preferably 0 <[E] ≦ 10 Formula [II] When higher than the upper limit of the above range, the blocking resistance is poor. , The rigidity decreases.

Physical properties (6): Fractionation at elevated temperature using ortho-dichlorobenzene as a solvent (TREF: Temper)
atture rising elution frac
The extraction amount extracted at 40 ° C. or lower is 2% by weight or less, preferably 1% by weight or less, and the extraction amount extracted at 50 ° C. or
Or less, preferably 4% by weight or less, and the amount extracted at 60 ° C. or less is 20% by weight or less, preferably 1% or less.
0% by weight or less. When orthodichlorobenzene is used as a solvent and any of the extraction amounts extracted at each temperature exceeds the above range, transparency and gloss after shrinkage are reduced, and hot-slip properties and blocking resistance are obtained. Further, since the composition distribution is not uniform, the pinhole resistance deteriorates. The extraction with ortho-dichlorobenzene is carried out by temperature-elution fractionation (TRE) using ortho-dichlorobenzene as a solvent.
F: Temperature Rising Elut
ion fraction). The measurement of TREF is based on the Journal of
Applied Polymer Science
Vol. 26, Nos. 4217-4231 (1981).

[0010] As the propylene · alpha-olefin random copolymer composed mainly of types such as propylene, for example, propylene main component and propylene with other 1-alkene (ethylene, 1-butene, 1-pentene, A binary copolymer with 1-hexene, 4-methylpentene-1 or the like, or propylene having propylene as a main component, ethylene and another 1-alkene (1-butene, 1-pentene, 1-hexene, 4
-Methylpentene-1 etc.).

[0011] Manufacturing takes propylene polymer can be produced by applying a conventionally known manufacturing method. The catalyst used in these productions is not particularly limited, but for example, a metallocene-based catalyst can be used. Further, a catalyst system containing a titanium-containing solid catalyst component and an organoaluminum compound as cocatalyst components can be mentioned.
As the titanium-containing solid catalyst component, a known carrier-supported catalyst component obtained by contacting a solid magnesium compound, titanium tetrahalide and an electron donating compound, titanium trichloride or a known component containing titanium trichloride as a main component Selected from the following catalyst components: Further, in addition to the solid catalyst component and the cocatalyst component, a catalyst system using a known electron-donating compound as the third component may be used.

[0012] Polymerization polymerization mode, the catalyst component and the monomer if efficiently contact may take any manner. Specifically, a slurry method using an inert solvent, a bulk method using propylene as a solvent without substantially using an inert solvent, a solution polymerization method, or a method in which each monomer is substantially gaseous without substantially using a liquid solvent Gas phase method or the like can be adopted. Also, continuous polymerization,
Also applies to batch polymerization. In the case of slurry polymerization,
As the polymerization solvent, a singly or a mixture of saturated aliphatic or aromatic hydrocarbons such as hexane, heptane, pentane, cyclohexane, benzene, and toluene is used.

(B) Anti-blocking agent The anti-blocking agent used in the propylene resin composition of the present invention has an average particle size of 10 μm or less, preferably 7 μm or less, particularly preferably 5 μm or less. If the average particle size exceeds the above range, the irregularities on the surface of the film become too large, and voids having these particles as nuclei become so negligible that the transparency is lowered. Measurement of Average Particle Size The average particle size of the magnesium silicate spherical fine powder used in the present invention is measured by a Coulter counter method. The type of the antiblocking agent used above is not particularly limited as long as it satisfies the above range, but a spherical one is preferable. Further, a spherical antiblocking agent is preferred. It is particularly preferable to use a sphericity (f) having a sphericity (f) of 0.7 or more determined by the following equation.

[0014]

(Equation 1)

(Where A is the cross-sectional area of the powder (mm ² ),
Dmax is the longest diameter (mm) of the same cross section, the value of sphericity given by this equation is in the range of 0 to 1, and 1 is true sphere. If the sphericity (f) is less than the above range, the obtained film has poor slipperiness. Measurement of sphericity (f) The sphericity (f) can be measured by measuring the cross-sectional area (mm ² ) of the powder and the longest diameter (mm) of the cross-section.
The specific measurement is performed by adding an epoxy resin to spherical fine particles of magnesium silicate, solidifying, cutting with a microtome, and measuring the cross section of the fine particles with an image analyzer. Examples of the anti-blocking agent for the spherical fine particles include JP-A-52-16954, JP-A-60-13813, and JP-A-6-7310.
No. 6, publicly known silicone resins, benzoguanamine / formaldehyde resins, benzoguanamine / melamine / formaldehyde resins, (meth) acrylic resins, spherical silica, magnesium silicate spherical fine particles, and the like are preferable because they are spherical and have a substantially uniform particle diameter. In particular, it is preferable to use spherical silica, magnesium silicate spherical fine particles, and (meth) acrylic resin.

(2) Amount ratio The amount of the antiblocking agent to be added is as follows: propylene / α-olefin random copolymer 1 containing propylene as a main component.
0.01 to 1 part by weight, preferably 0.05 to 0.6 part by weight, particularly preferably 0.1 to 0.
It is blended in a ratio of 4 parts by weight. When the addition amount is less than the above range, there is no effect of the hot slip property, and when the addition amount exceeds the above range, the transparency is reduced.

[II] Preparation of Composition The propylene resin composition of the present invention is prepared by blending an antiblocking agent with a propylene / α-olefin random copolymer containing propylene as a main component to produce a composition. Any method may be used as long as these components are uniformly dispersed and mixed.However, after weighing various additives each containing a powdered propylene / α-olefin random copolymer as a main component, powder The mixture is uniformly mixed and dispersed uniformly with a ribbon blender, Henschel mixer or the like as it is, and the powdery mixture is melt-kneaded using a screw extruder such as a single screw extruder or a twin screw extruder, and then cooled,
It is particularly desirable to cut and use as a pellet-like mixture. In addition, to prepare a pellet-like compound highly blended in a masterbatch of a spherical anti-blocking agent, and to mix the pellet-like compound highly blended in the masterbatch and un-added pellets during film production It is also possible to form a film within the compounding range used in the present invention. In the propylene-based resin composition of the present invention such as additives , if necessary, an antioxidant, a slip agent, a neutralizing agent, a weathering agent, a lubricant, an antistatic agent, an anti-fogging agent, a pigment, a filler, etc. Known additives can be contained.

[III] Stretched Film (1) Production of Stretched Film The stretched film of the present invention is produced by the same method as that for producing an ordinary stretched film using the propylene resin composition as a raw material resin. be able to. Specifically, a method used in the production of ordinary industrial stretched films, for example, by employing a stretching method such as roll stretching, tenter stretching, tubular stretching, a pantograph type tabletop stretching machine, at least in the uniaxial direction. It can be obtained by stretching. In the case of biaxial stretching, any of simultaneous, sequential or multi-stage stretching in two directions can be applied. The stretching direction is generally in the range of 2.0 to 12 times, preferably 3.0 to 10 times, one direction, and the thickness of the stretched film is generally 5 to 10 times.
The range is 200 μm, preferably 8 to 100 μm. (2) Post-treatment In addition, it is common to perform a heat treatment while stretching or relaxing a few percent after stretching, and then, if necessary, a surface treatment such as corona discharge in air or an inert gas may be performed. .

[0019]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. [Evaluation Method] Evaluation methods of the films performed in Examples and Comparative Examples are described below. (1) Melt flow rate (MFR) Melt flow rate according to JIS-K6758 for the polypropylene test method (conditions: 230 ° C, load 2.16 kgf)
(Unit: g / 10 minutes). (2) Memory effect (ME) The temperature inside the cylinder of the melt indexer is set to 190 ° C, and the orifice is 8.00 mm long and 1.00 mm in diameter.
φ, L / D = 8 is used. In addition, a measuring cylinder containing ethyl alcohol is placed immediately below the orifice (the distance between the orifice and the liquid level of ethyl alcohol is set to 20 ± 2 mm). In this state, put the sample into the cylinder,
The load is adjusted so that the amount of extrusion per minute is 0.1 ± 0.03 g, and the extrudate after 6 minutes to 7 minutes is dropped in ethanol, solidified, and collected. The maximum and minimum values of the diameter of the strand-shaped sample of the extrudate sampled were measured at three places of 1 cm from the upper end, 1 cm from the lower end, and the central part, and the average value of the diameters measured at six places was defined as ME. . (3) Melting peak temperature and melting end temperature by differential scanning calorimeter (DSC) Using a DSC manufactured by Seiko, take a sample amount of 5.0 mg, hold at 200 ° C for 5 minutes, and then 10 ° C / 40 ° C to 40 ° C.
The crystallization was performed at a temperature lowering speed of 1 minute and the melting peak temperature and the melting end temperature were further evaluated when melting was performed at a temperature increasing speed of 10 ° C./minute (unit: ° C.).

(4) Comonomer concentration Measured by 13C-nuclear magnetic resonance spectroscopy. Apparatus: JEOL-GSX270 (manufactured by JEOL Ltd.) Concentration: 300 mg / 2 ml Solvent: orthodichlorobenzene (5) Measure the amount of extraction by temperature rising elution fractionation (TREF) 40 ° C. or less, 50 ° C. by temperature rising elution fractionation (TREF)
C. or less and the extraction amount at 60 ° C. or less were measured. Apparatus: CFC T150A type, manufactured by Mitsubishi Chemical Corporation Column: AD80M / S, 3 columns, Showa Denko Co., Ltd. Concentration: 40 mg / 10 ml Solvent: orthodichlorobenzene (6) Heat shrinkage ratio A 5 cm square film test piece is placed in a glycerin bath at a predetermined temperature. The shrinkage of MD and TD when immersed for 10 seconds is measured. Shrinkage (%) = [(dimension before heating−dimension after heating) / dimension before heating] × 100 The shrinkage is 8% or more at 80 ° C., 15% or more at 100 ° C.
If it is 40% or more at 120 ° C, it is judged to be good.

(7) Transparency (Haze) The obtained film was measured with a haze meter according to ASTM-D1003. When the haze value is low, it means that the transparency is excellent. If the haze is 4.0% or less, it is judged to be good. (8) Gloss According to JIS-Z8741, the obtained film was measured with a gloss meter. High gloss means excellent gloss. If the gloss is 120% or more, it is determined to be good. (9) Rigidity (Tensile Modulus) The obtained film was measured by an Instron type autograph in accordance with ISO-R1184 (unit: kg / kg).
cm ² ). The higher the elastic modulus, the higher the rigidity.

(10) Transparency (Haze) and Gloss (Gloss) After Shrinkage The obtained film was coated on a commercially available video tape (100 m wide).
mx length 200 mm x thickness 25 mm) was cut so as to have a margin of 15%, superimposed on a video tape, melt-sealed at 230 ° C, and then shrunk in a shrink tunnel. The haze and gloss of this film were measured. The temperature set in the tunnel was 160 ° C., and the heating time was 10 seconds. 3. Haze after shrinkage is 4.
If the difference between the haze before shrinkage and the haze after shrinkage is 0.5% or less at 0% or less, it is judged to be good. If the gloss after shrinkage is 120% or more and the difference between the gloss before shrinkage and the gloss after shrinkage is 10% or less, it is judged to be good. (11) Blocking property The same surface of a sample film of 2 cm (width) x 15 cm (length) is overlapped over a length of 5 cm, and after conditioning for 24 hours in an atmosphere of a temperature of 40 ° C under a load of 100 g / cm ² , After removing the load and sufficiently adjusting the temperature to 23 ° C., the tensile tester was opened, and the force required for shearing and peeling the sample at a speed of 200 mm / min was determined (unit: g / 10 cm ² ). The smaller this value is, the better the blocking resistance is. 1,000g /
If it is less than 10 cm ² , it is judged that the blocking resistance is good.

(12) Hot slip property (unit: coefficient of sliding friction) Ambient temperature 50 ° C, 55 ° C, 60 ° C, relative humidity 65% R
The coefficient of static friction is represented by a coefficient of static friction measured by a method specified in ASTM-D1894-63 in a constant temperature chamber of H. Hot slip property is 0.4 or less at 50 ° C, 0.6 or less at 55 ° C, 60
If it is 1.0 or less at ° C, it is judged to be good. (13) Pinhole resistance at the time of fusing sealing
mx length 200 mm x thickness 25 mm), cut to a margin of 15%, superimposed on videotape, sealed by fusing at 230 ° C, and tested in a shrink tunnel for 20 pieces. A shrink test was performed.
The temperature set in the tunnel is 160 ° C and the heating time (passing time 1
0 second). If there were two or more holes of 2 mm or more or three or more holes of less than 2 mm in the seal portion of this film, it was regarded as a defective product and the following judgment was made. Judgment ○: The pinhole resistance is good when the non-defective rate is 80% or more with respect to the whole test number. Poor hole performance Judgment X: Pinhole resistance is poor if the non-defective rate is less than 60% of the total number of test pieces

Example 1 [Preparation of composition] Melt flow rate (MFR) 2.5
g / 10 min, memory effect (ME) 1.24, ethylene content 1.7 mol%, melting peak temperature (TP) 139.6 ° C. determined by DSC, melting end temperature (TE) 14
3.4 ° C, Orthodichlorobenzene is used as a solvent, and temperature rise elution fractionation (TREF) below 40 ° C
0% by weight, the amount extracted by temperature rise elution fractionation (TREF) at 50 ° C. or less is 0% by weight, and the amount extracted by temperature rise elution fractionation (TREF) at 60 ° C. or less is 0% by weight. % Of propylene / ethylene random copolymer and 100 parts by weight of tetrakis [methylene-3- (3 ′,
5′-di-tert-butyl-4-hydroxyphenyl) propionate] methane in an amount of 0.05 part by weight, tris- (2,
4-di-t-butylphenyl) phosphite to 0.05
Parts by weight, 0.1% calcium stearate as a neutralizing agent
Parts by weight, 0.25 parts by weight of magnesium silicate spherical fine particles (average particle size: 2.0 μm) as an anti-blocking agent, 0.05 parts by weight of oleamide and 0.05 parts by weight of erucamide as lubricants After high-speed mixing at room temperature for 1 minute with a Henschel mixer,
The mixture was melted, kneaded, cooled, and cut at 230 ° C. with a φ extruder to obtain a pelletized propylene-based resin composition.

[Production of Stretched Film] Using this resin composition, a 300 μm sheet was obtained by a pressing method, and a 90 mm square sheet was collected therefrom to obtain a biaxially stretched film under the following conditions. Stretching machine: Table-top biaxial stretching machine manufactured by Toyo Seiki Temperature: 140 ° C. Residual heat time: 2 minutes Stretching ratio: MD 4.5 times, TD 4.5 times Stretching speed: 10 m / min Film having a thickness of about 15 μm obtained by the above method. Table 1 shows the evaluation results.

Example 2 Example 2 was carried out in the same manner as in Example 1 except that the type of the antiblocking agent was changed to true spherical crosslinked polymethyl methacrylate particles (average particle size: 2.0 μm). Table 1 shows the evaluation results of the obtained films.

Example 3 Melt flow rate (MFR) 2.5 g / 10 min, memory effect (ME) 1.23, ethylene content 4.6
Mol%, melting peak temperature (TP) 12 determined by DSC
8.3 ° C., melting end temperature (TE) 132.9 ° C., using ortho-dichlorobenzene as a solvent, extraction at 40 ° C. or less by temperature rising elution fractionation (TREF): 0% by weight, 50 ° C. or less The amount extracted by the temperature rise elution fractionation (TREF) was 0% by weight,
The procedure was carried out in the same manner as in Example 1 except that a propylene / ethylene random copolymer having an extraction amount of 0.6% by weight, which was extracted by temperature rise elution fractionation (TREF) at a temperature of not more than ℃ was used. Table 1 shows the evaluation results of the obtained films.

Example 4 Melt flow rate (MFR) 2.5 g / 10 min, memory effect (ME) 1.25, ethylene content 6.5
Mol%, melting peak temperature (TP) 11 determined by DSC
9.9 ° C., melting end temperature (TE) 125.9 ° C., orthodichlorobenzene was used as a solvent, and the extraction amount by temperature rising elution fractionation (TREF) at 40 ° C. or less was 0.7% by weight, 50 ° C. In the following, the amount of extraction extracted by temperature rise elution fractionation (TREF) is 1.8% by weight.
5.6% by weight of propylene
The procedure was performed in the same manner as in Example 1 except that an ethylene random copolymer was used. Table 1 shows the evaluation results of the obtained films.
Shown in

Example 5 Melt flow rate (MFR) 2.5 g / 10 min, memory effect (ME) 1.24, ethylene content 1.6
Mol%, butene content: 4.9 mol%, melting peak temperature (TP) determined by DSC: 129.5 ° C., melting end temperature (T
E) Elevated temperature elution fractionation (TR) at 133.5 ° C and orthodichlorobenzene as a solvent at 40 ° C or lower
EF) extracted by 0.1% by weight, 50 ° C.
In the following, the amount of extraction extracted by temperature-rise elution fractionation (TREF) is 0.4% by weight, and the amount of extraction extracted by temperature-rise elution fractionation (TREF) below 60 ° C is 1.6% by weight. The procedure was performed in the same manner as in Example 1 except that the original random copolymer was used. Table 1 shows the evaluation results of the obtained films.

Comparative Example 1 Melt flow rate (MFR) 2.5 g / 10 min, memory effect (ME) 1.23, melting peak temperature (TP) determined by DSC at 148.1 ° C., melting end temperature (T
E) 152.7 ° C., orthodichlorobenzene was used as a solvent, and the temperature was raised at 40 ° C. or lower.
The extraction amount extracted by EF) is 0% by weight, the extraction amount extracted by temperature rising elution fractionation (TREF) at 50 ° C or lower is 0% by weight, and the extraction amount extracted by temperature rising elution fractionation (TREF) at 60 ° C or lower is 0%. The procedure was performed in the same manner as in Example 1 except that 0% by weight of the polypropylene polymer was used. Table 2 shows the evaluation results of the obtained films.

Comparative Example 2 Melt flow rate (MFR) 2.5 g / 10 min, memory effect (ME) 1.58, melting peak temperature (TP) 140.0 ° C. determined by DSC, melting end temperature (T
E) Elevated temperature elution fractionation at 148.0 ° C. and orthodichlorobenzene at 40 ° C. or less using TR (TR)
EF) was extracted at 0.6% by weight at 50 ° C.
In the following, a polypropylene polymer having an extraction amount of 3.2% by weight extracted by temperature rising elution fractionation (TREF) and an extraction amount of 9.5% by weight extracted by temperature rising elution fractionation (TREF) below 60 ° C. was used. Other than that, it carried out similarly to Example 1. Table 2 shows the evaluation results of the obtained films.

Comparative Example 3 Melt flow rate (MFR) 2.5 g / 10 min, memory effect (ME) 1.40, melting peak temperature (TP) 135.6 ° C. determined by DSC, melting end temperature (T
E) Elevated temperature elution fractionation (TR) at 143.2 ° C. and orthodichlorobenzene as a solvent at 40 ° C. or lower
The amount of extraction extracted by EF) is 10.9% by weight, 50
A polypropylene polymer having an extraction amount of 15.2% by weight extracted by temperature rising elution fractionation (TREF) at a temperature below 60 ° C. and an extraction amount of 21.0% by weight extracted by temperature rising elution fractionation (TREF) below 60 ° C. is used. The procedure was performed in the same manner as in Example 1 except that Table 2 shows the evaluation results of the obtained films.

Comparative Example 4 Melt flow rate (MFR) 2.5 g / 10 min, memory effect (ME) 1.38, ethylene content 6 mol%, melting peak temperature (TP) 137.1 determined by DSC
C., melting end temperature (TE) 156.9.degree. C., using ortho-dichlorobenzene as a solvent, 1.4 wt% extracted by temperature rising elution fractionation (TREF) at 40.degree. C. or less, and temperature at 50.degree. C. or less. 3.8% by weight of the extract extracted by rising elution fractionation (TREF),
The procedure was performed in the same manner as in Example 1 except that a propylene / ethylene random copolymer having an extraction amount of 15.0% by weight extracted at 60 ° C. or lower by temperature rising elution fractionation (TREF) was used. Table 2 shows the evaluation results of the obtained films.

Comparative Example 5 Melt flow rate (MFR) 2.5 g / 10 min, memory effect (ME) 1.39, melting peak temperature (TP) 126.8 ° C. determined by DSC, melting end temperature (T
E) 134.8 ° C., using ortho-dichlorobenzene as a solvent, and elevating the temperature at 40 ° C. or less by elution fractionation (TR
The amount extracted by EF) is 15.5% by weight, 50
The extraction amount extracted by temperature rise elution fractionation (TREF) at 2 ° C. or lower is 24.0% by weight, the extract amount extracted by temperature rise elution fractionation (TREF) at 60 ° C. or less is 36.9% by weight, and the weight determined by GPC. Example 1 was repeated except that a polypropylene polymer having a ratio of the average molecular weight to the number average molecular weight of 4.0 was used. Table 2 shows the evaluation results of the obtained films.

Comparative Example 6 The procedure of Example 1 was repeated, except that the average particle size of the antiblocking agent was changed to 12.0 μm. Table 2 shows the evaluation results of the obtained films.

Comparative Example 7 In Example 1, the concentration of the anti-blocking agent was set to 1
It carried out like Example 1 except having changed into 2 weight%. Table 2 shows the evaluation results of the obtained films.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

The shrink wrapping film obtained by the method of the present invention has high shrinkage at low temperature by blending a specific propylene resin with a specific anti-blocking agent, and has transparency, gloss, Excellent rigidity and blocking resistance,
In addition, it is a film with excellent hot-slip property during packaging, pinhole resistance during shrink wrapping after fusing and sealing, and with little loss of transparency and gloss after shrinkage. It has a very high practical value.

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Claims (2)

[Claims] An antiblocking agent having an average particle size of 10 μm or less is added to 100 parts by weight of a propylene / α-olefin random copolymer containing propylene as a main component satisfying the following physical properties (1) to (6). A propylene-based resin composition comprising 0.01 to 1.0 part by weight. Physical properties (1): Melt flow rate (MFR) is 1.0
２０20 g / 10 min. Physical properties (2): Memory effect (ME) is 0.9-
Physical property (3): The temperature [TP] of the main melting peak determined by a differential scanning calorimeter (DSC) is 100 to 145 ° C. Physical property (4): Differential scanning calorimeter The melting end temperature [TE] (° C.) determined by (DSC) is [TE] − [TP] ≦ 8
Physical properties (5): a random copolymer obtained by combining an α-olefin component having 2 or 4 to 20 carbon atoms with propylene, wherein at least one α-olefin component is contained, and an α-olefin component is contained. The amount [E] (mol%) is within the range represented by the following formulas [I] and [II]; (140− [TP]) / 10.2 ≦ [E] ≦ (160− [TP] ] /2.6 Formula [I] 0 <[E] ≦ 23 Formula [II] Physical properties (6): Measurement by temperature-rise elution fractionation (TREF) using orthodichlorobenzene as a solvent At 40 ° C
The extraction amount extracted below is 2.0% by weight or less, the extraction amount extracted at 50 ° C or less is 5.0% by weight or less, and 60 ° C
The extraction amount extracted below is 20% by weight or less, 2. An antiblocking agent having an average particle size of 10 μm or less is added to 100 parts by weight of a propylene / α-olefin random copolymer containing propylene as a main component satisfying the following physical properties (1) to (6). A stretched film obtained by forming a film using a propylene-based resin composition blended in an amount of 0.01 to 1.0 part by weight, and then stretching the film at least in a uniaxial direction. Physical properties (1): Melt flow rate (MFR) is 1.0
２０20 g / 10 min. Physical properties (2): Memory effect (ME) is 0.9-
Physical property (3): The temperature [TP] of the main melting peak determined by a differential scanning calorimeter (DSC) is 100 to 145 ° C. Physical property (4): Differential scanning calorimeter The melting end temperature [TE] (° C.) determined by (DSC) is [TE] − [TP] ≦ 8
Physical properties (5): a random copolymer obtained by combining an α-olefin component having 2 or 4 to 20 carbon atoms with propylene, wherein at least one α-olefin component is contained, and an α-olefin component is contained. The amount [E] (mol%) is within the range represented by the following formulas [I] and [II]; (140− [TP]) / 10.2 ≦ [E] ≦ (160− [TP] ] /2.6 Formula [I] 0 <[E] ≦ 23 Formula [II] Physical properties (6): Measurement by temperature-rise elution fractionation (TREF) using orthodichlorobenzene as a solvent At 40 ° C
The extraction amount extracted below is 2.0% by weight or less, the extraction amount extracted at 50 ° C or less is 5.0% by weight or less, and 60 ° C
The amount extracted below is 20.0% by weight or less;