JP5252478B2 - Foamed resin composition for air-cooled inflation and air-cooled inflation foam film using the same - Google Patents

Description

  The present invention relates to a foamed resin composition for air-cooled inflation and an air-cooled inflation foam film using the same, and more specifically, air-cooled inflation foam having uniform fine cells in air-cooled inflation molding and obtaining a film having an excellent appearance. The present invention relates to a resin composition and an air-cooled inflation foam film using the same.

Foamed films using propylene-based resins are preferred for packaging ceremonial gifts, gifts, and souvenirs. However, in general, propylene-based resin has high crystallinity and it is difficult to adjust the melt viscosity at the time of extrusion, so it is difficult to obtain uniform and fine foam cells, and it is difficult to make fine bubbles in the film. It was difficult to obtain a new product.
In order to solve such problems, a heat-shrinkable foam film using a specific crystalline propylene / α-olefin copolymer (Patent Document 1) and a polypropylene-based laminated foam heat-shrinkable film having a specific laminated structure (Patent Document 2), a technology relating to a polypropylene-based stretched stretched film (Patent Document 3) using a specific propylene-based resin is disclosed. However, in the manufacturing method capable of rapid cooling as implemented here, it is easy to obtain a foam film having a relatively good foam cell, but in the air-cooled inflation method in which rapid cooling is not possible due to the structure, a good foam cell is used. The present condition is that the foam film which has it cannot be obtained.
The film production method includes a water-cooled inflation method, an air-cooled inflation method, a T-die method, a biaxial stretching method, and the like, which are appropriately selected in consideration of economic efficiency and required performance of the film. Above all, the air-cooled inflation method is simple in equipment, easy to change the width of the film simply by adjusting the blow ratio, and has good workability, and can be molded at low temperatures, resulting in a low odor film. For this reason, if a foamed film can be obtained by this molding method, it will be extremely industrially beneficial.
As a technique for obtaining a foamed film using an air-cooled inflation method, a method using a specific propylene resin composition (Patent Document 4) and a foam film for shrink label (Patent Document 5) having specific physical properties are disclosed. However, even with the propylene-based resin composition described here, it is extremely difficult to obtain a foam film having excellent appearance with uniform fine foam cells in the air-cooled inflation method. The film has a rough surface and is not suitable for packaging applications because it has poor printability.
JP 59-176335 A Japanese Patent Laid-Open No. 1-286834 JP 2007-231192 A Japanese Patent Laid-Open No. 2007-2058 JP 2007-84696 A

  In view of the above problems, an object of the present invention is to provide a foamed resin composition for air-cooled inflation that can obtain a foam film having uniform appearance and excellent appearance in air-cooled inflation molding, and air-cooled inflation foam using the same. A film is provided.

As a result of intensive studies to solve the above problems, the present inventors have found that uniform fine foam cells can be obtained even in the air-cooled inflation method, which is a production method in which rapid cooling cannot be performed by using a specific propylene-based resin composition. It has been found that a foam film having excellent appearance can be obtained, and the present invention has been completed.
That is, by solving the gist of the present invention as follows, the problem can be solved, and it has the following characteristics.

  The main feature of the present invention is that 30 to 95% by weight of a propylene-based resin (A) polymerized using a metallocene catalyst with an MFR of 0.5 to 4 g / 10 min and an MFR of 0.1 to 20 g / 10 min, melted 100 parts by weight of a resin mixture composed of a propylene-based resin (B) having a tension (190 ° C., caliber 2 mm) of 1.0 to 50 cN and strain hardening under elongational flow. Thus, the foamed resin composition for air-cooled inflation is obtained by blending 0.05 to 6.0 weight of a foaming agent.

Another feature of the present invention is the foamed resin composition for air-cooled inflation, wherein the propylene-based resin (A) satisfies the following characteristics (i) to (iv).
(I) MFR is 0.5 to 3.5 g / 10 min,
(Ii) the molecular weight distribution (Mw / Mn) measured by GPC method is 1.5-4,
(Iii) In the elution curve obtained by temperature rising elution fractionation (TREF), it is the difference between the temperature (T ₄₀ ) extracted by 40% by weight and the temperature (T ₉₀ ) extracted by 90% by weight (T ₉₀ -T _40). ) Is 6 ° C. or less.

Another feature of the present invention is that the propylene-based resin (B) contains the following components (a) and (b), and the component (b) is 0.01 to 20 parts per 100 parts by weight of the component (a). The present invention lies in a foamed resin composition for air-cooled inflation characterized by being part by weight.
(A) a propylene homopolymer or a propylene / α-olefin copolymer containing 50% by weight or more of a propylene homopolymer or an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 0.2 to 10 dl / g .
(B) An ethylene homopolymer or an ethylene / α-olefin copolymer containing 50% by weight or more of an ethylene polymer having an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 15 to 100 dl / g.

  Another feature of the present invention resides in an air-cooled inflation foam film obtained by using the above-mentioned foamed resin composition for air-cooled inflation.

  The air-cooled inflation foamed film obtained by the foamed resin composition for air-cooled inflation of the present invention has good moldability even in the air-cooled inflation method in which it is difficult to obtain a foamed film because it is difficult to rapidly cool, and the foamed cells are very fine and uniform. Since the appearance is also extremely excellent, the printability is good and it is extremely suitable for packaging applications.

  The foamed resin composition for air-cooled inflation of the present invention comprises 30 to 95% by weight of a propylene-based resin (A) having an MFR of 0.5 to 4 g / 10 min polymerized using a metallocene catalyst, and an MFR of 0.1 to 20 g / 100 wt. Of resin mixture comprising 10 min, a melt tension (190 ° C., caliber 2 mm) of 1.0 to 50 cN and 70 to 5 wt% of propylene-based resin (B) having strain hardening property under elongational flow. A foaming agent is mix | blended 0.05-6.0 weight with respect to a part.

The constituent components will be described in detail below.
1. Component propylene resin (A)
The propylene resin (A) used in the present invention is a propylene resin having an MFR of 0.5 to 4 g / 10 min polymerized using a metallocene catalyst.
Such a propylene-based resin may be either a propylene homopolymer or a copolymer of propylene and another α-olefin.
Moreover, it is preferable that the propylene-type resin used by this invention has the following characteristics (i)-(iii). Hereinafter, each characteristic will be described.

Characteristic (i) MFR
The melt flow rate (MFR) of the propylene-based resin (A) used in the present invention is 0.5 to 4 g / 10 min, preferably 0.5 to 3.5 g / 10 min, more preferably 1 to 3 g / min. 10 min. When the MFR is less than 0.5 g / 10 min, the viscosity of the molten resin increases, and it is difficult to form foam cells, so the expansion ratio does not increase. When the MFR exceeds 4 g / 10 min, the viscosity of the molten resin decreases and the foam cell diameter becomes finer. Is difficult and unfavorable.
Here, MFR is a value measured at a heating temperature of 230 ° C. and a load of 21.2 N in accordance with JIS K7210.

(Ii) Molecular weight distribution (Mw / Mn)
The molecular weight distribution (Mw / Mn) measured by the gel permeation (GPC) method of the propylene-based resin (A) used in the present invention is preferably 1.5 to 4, and less than 1.8 to 3 It is more preferable that When Mw / Mn is less than 1.5, it is difficult to obtain with the current polymerization technique, and when it exceeds 4, the viscosity in the polymer becomes non-uniform and it is difficult to make the foam cell diameter uniform, which is not preferable. The method for adjusting the molecular weight distribution is preferably polymerization using a catalyst system in which two or more metallocene catalyst components are used in combination or a catalyst system in which two or more metallocene complexes are used in combination, or two or more stages of multistage polymerization at the time of polymerization. It can be controlled by doing. Conversely, in order to adjust the molecular weight distribution narrowly, it can be adjusted by polymerizing a propylene polymer and then melt-kneading it using an organic peroxide.

Here, the molecular weight distribution is obtained by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn), and is obtained by measurement by a gel permeation chromatography (GPC) method.
Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene.
The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation. F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A calibration curve is prepared 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 × Mα 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.
Apparatus: GPC (ALC / GPC 150C) manufactured by WATERS
Detector: MIRAN 1A IR detector (measured wavelength: 3.42 μm) manufactured by FOXBORO
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: 0.2ml
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.

_{(Iii) T 90} -T 40 (elution volume difference temperature by TREF)
40% by weight extraction temperature (T ₄₀ ) and 90% by weight extraction temperature (T ₉₀ ) in the integral elution curve obtained by temperature rising elution fractionation (TREF) of the propylene-based resin (A) used in the present invention. The difference (T ₉₀ −T ₄₀ ) is preferably 6 ° C. or less. The temperature (T ₉₀ -T ₄₀ ) obtained here is used as an index for knowing the degree of crystallinity distribution of the propylene-based resin (A) to be used. When this value exceeds 7 ° C., the crystallinity in the polymer This is not preferable because the distribution becomes non-uniform and it may be difficult to make the foam cell diameter uniform.

In the case of a propylene-α-olefin copolymer, it is necessary to use a metallocene catalyst in order to make (T ₉₀ -T ₄₀ ) a specific narrow range as described above. When a Ziegler-Natta catalyst is used, it is difficult to achieve a specific narrow range as described above.
The method of adjusting (T ₉₀ -T ₄₀ ) of the propylene-based resin is carried out by polymerizing using a catalyst system using two or more kinds of catalyst components or a catalyst system using two or more kinds of complexes in combination (T ₉₀ -T ₄₀₎ can be a big adjustment.

Here, in order to obtain an elution curve by temperature rising elution fractionation (TREF), the polymer is completely dissolved in a solvent and supplied to a cross fractionation apparatus equipped with a column, and then cooled to 0 ° C. at a predetermined cooling rate. After forming a thin polymer layer on the surface of the active carrier and keeping it cool for a while, the temperature is raised continuously or stepwise, and the amount of polymer eluted up to that temperature is continuously measured. What is necessary is to draw a curve representing the relationship. T ₄₀ is the temperature at which 40% of the thin polymer layer formed on the surface of the inert carrier is eluted, and T ₉₀ is the temperature at which 90% is eluted. Measurement conditions are as follows.
Apparatus: CFC T150A type manufactured by Mitsubishi Chemical Corporation Solvent: o-dichlorobenzene Measurement concentration: 4 mg / ml
Column: Showa Denko Co., Ltd. AD80M / S
Column size: 0.46mm diameter x 15cm
Inactive carrier: glass beads (0.1 mm diameter)
Cooling rate: 100 ° C / 120 minutes

The propylene-based resin (A) used in the present invention needs to be polymerized using a metallocene catalyst. Use of polypropylene polymerized with a catalyst other than a metallocene catalyst is not preferable because the molecular weight distribution is wide, the composition distribution is non-uniform, and it is difficult to make the foam cell diameter uniform and fine.
The metallocene catalyst used for the polymerization of the propylene-based resin used in the present invention includes (i) a transition metal compound belonging to Group 4 of the periodic table (so-called metallocene compound) containing a ligand having a cyclopentadienyl skeleton, and (ii) It is a catalyst comprising a cocatalyst that can be activated to a stable ionic state by reacting with a metallocene compound and, if necessary, (iii) an organoaluminum compound, and any known catalyst can be used. The metallocene compound is preferably a bridged metallocene compound capable of stereoregular polymerization of propylene, and more preferably a bridged metallocene compound capable of isoregular polymerization of propylene. Each component will be described.

  Examples of the (a) metallocene compound include JP-A-60-35007, JP-A-63-130314, JP-A-63-295607, JP-A-1-275609, JP-A-2-41303, and JP-A-2-41303. JP-A-2-131488, JP-A-2-76887, JP-A-3-163088, JP-A-4-300787, JP-A-4-21694, JP-A-5-43616, JP-A-5-209913, JP-A-6-6 No. 239914, JP-A-7-504934, and JP-A-8-85708.

  More specifically, methylene bis (2-methylindenyl) zirconium dichloride, ethylenebis (2-methylindenyl) zirconium dichloride, ethylene 1,2- (4-phenylindenyl) (2-methyl-4-phenyl) -4H-azulenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (fluorenyl) zirconium dichloride, isopropylidene (4-methylcyclopentadienyl) (3-t-butylindenyl) zirconium dichloride, dimethylsilylene (2- Methyl-4-t-butyl-cyclopentadienyl) (3′-t-butyl-5′-methyl-cyclopentadienyl) zirconium dichloride, dimethylsilylenebis (indenyl) zirconium dichloride, dimethylsilylenebis (4,5 6,7-tetrahydroindenyl) zirconium dichloride, dimethylsilylene bis [1- (2-methyl-4-phenylindenyl)] zirconium dichloride, dimethylsilylene bis [1- (2-ethyl-4-phenylindenyl)] Zirconium dichloride, dimethylsilylenebis [4- (1-phenyl-3-methylindenyl)] zirconium dichloride, dimethylsilylene (fluorenyl) t-butylamidozirconium dichloride, methylphenylsilylenebis [1- (2-methyl-4, (1-naphthyl) -indenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4,5-benzoindenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4-phenyl-) 4H-azuleni ] Zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azulenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4-naphthyl-4H-azurenyl) ] Zirconium dichloride, diphenylsilylene bis [1- (2-methyl-4- (4-chlorophenyl) -4H-azulenyl)] zirconium dichloride, dimethylsilylene bis [1- (2-ethyl-4- (3-fluorobiphenyl) Ryl) -4H-azurenyl)] zirconium dichloride, dimethylgermylenebis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylgermylenebis [1- (2-ethyl) -4-phenylindenyl)] zirconium di Zirconium compounds such as chloride can be exemplified.

In the above, compounds in which zirconium is replaced with titanium or hafnium can be used in the same manner. In some cases, a mixture of a zirconium compound and a hafnium compound can be used. Further, the chloride can be replaced with other halogen compounds, hydrocarbon groups such as methyl, isobutyl and benzyl, amide groups such as dimethylamide and diethylamide, alkoxide groups such as methoxy group and phenoxy group, hydride groups and the like. Among these, a metallocene compound in which an indenyl group or an azulenyl group is crosslinked with silicon or a germyl group is preferable.
The metallocene compound may be used by being supported on an inorganic or organic compound carrier. The carrier is preferably an inorganic or organic porous compound. Specifically, ion-exchange layered silicate, zeolite, SiO ₂ , Al ₂ O ₃ , silica alumina, MgO, ZrO ₂ , TiO ₂ , B Examples include inorganic compounds such as ₂ O ₃ , CaO, ZnO, BaO, and ThO ₂ , organic compounds composed of porous polyolefin, styrene / divinylbenzene copolymer, olefin / acrylic acid copolymer, and the like, or a mixture thereof. It is done.

  (B) As a co-catalyst that can be activated to a stable ionic state by reacting with a metallocene compound, an organoaluminum oxy compound (for example, an aluminoxane compound), an ion-exchange layered silicate, a Lewis acid, a boron-containing compound, an ionic compound And fluorine-containing organic compounds.

(Iii) Examples of the organoaluminum compound include trialkylaluminum such as triethylaluminum, triisopropylaluminum, and triisobutylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, alkylaluminum dihalide, alkylaluminum hydride, and organoaluminum alkoxide. Can be mentioned.

Examples of the polymerization method include a slurry method using an inert solvent in the presence of the catalyst, a solution method, a gas phase method substantially using no solvent, or a bulk polymerization method using a polymerization monomer as a solvent. . As a method for obtaining the propylene-based resin (A) used in the present invention, particularly a propylene / α-olefin random copolymer, for example, the polymerization temperature and the comonomer amount are adjusted to appropriately control the molecular weight and crystallinity distribution. Thus, a desired polymer can be obtained.
Such a propylene / α-olefin random copolymer may be appropriately selected from those commercially available as metallocene polypropylene. Examples of commercially available products include “Wintech” manufactured by Nippon Polypro.
The compounding quantity of the propylene-type resin (A) contained in the resin mixture used by this invention is 30 to 95 weight%, Preferably it is 50 to 90 weight%, More preferably, it is 60 to 80 weight%. If it is significantly less than 30% by weight, it becomes difficult to make the foamed cells fine during molding. If it exceeds 95% by weight, foam breakage occurs during molding due to insufficient cooling of the film.

Propylene resin (B)
The propylene-based resin (B) used in the present invention has an MFR of 0.1 to 20 g / 10 min, a melt tension (190 ° C., caliber of 2 mm) of 1.0 to 50 cN, and has strain-hardening properties under elongation flow. Propylene-based resin.
Such a propylene-based resin may be either a propylene homopolymer or a copolymer of propylene and another α-olefin. The olefin other than propylene copolymerized with propylene is not particularly limited, but an olefin having 2 to 12 carbon atoms is preferably used. Specific examples include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl-1-pentene. These olefins are There may be two types as well as one.
Specific examples of the propylene copolymer include propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-pentene copolymer, propylene-1-hexene copolymer, propylene- 1-octene copolymer, propylene-1-decene copolymer, propylene-4-methyl-1-pentene copolymer, and propylene-3-methyl-1-pentene copolymer. As a coalescence, it is preferable to contain a propylene polymer unit normally 50weight% or more, Preferably it contains 80 weight% or more, More preferably, it contains 85 weight% or more.
The melt flow rate (MFR) of the propylene-based resin (B) used in the present invention is 0.1 to 20 g / 10 min, and preferably 0.5 to 15 g / 10 min. If the MFR is less than 0.1 g / 10 min, the spreadability at the time of molding deteriorates and film breakage occurs. If it exceeds 20 g / 10 min, the bubble film is broken and the film is broken.
Here, MFR is a value measured in accordance with JIS-K7210 (230 ° C., 21.2 N).

The melt tension of the propylene-based resin (B) used in the present invention is 1.0 to 50 cN, preferably 2 to 50 cN, and more preferably 4 to 50 cN. When the melt tension is in the above range, a foamed film having a fine and large number of bubbles can be obtained.
Here, the melt tension is a value obtained when the resin is extruded from an orifice of 2.095 × 40 mm in length at a temperature of 190 ° C. and a speed of 20 m / min, and the winding speed is gradually increased and becomes constant. .
The propylene-based resin (B) used in the present invention has strain-hardening properties under elongation flow.
The melt tension is improved by increasing the molecular weight of the resin (decreasing the melt flow rate), but the conventional polypropylene resin does not exhibit strain hardening in uniaxial elongational flow, and both are regarded as the same. Can not. In foam molding, the process from the bubble growth stage until the bubbles are fixed by cooling is an elongation flow of the resin, and a sudden increase in viscosity accompanying deformation of the resin, a so-called strain hardening phenomenon is important. When bubbles grow, in the case of strain-hardening polypropylene resin, even if only a part of the bubble is deformed, the viscosity of that part rapidly rises along with the deformation, and the surrounding area is stretched. A foam holding air bubbles independent of the film is obtained.
Here, strain hardening means a non-linear phenomenon that shows a sudden increase in viscosity together with elongational viscosity at a temperature of 180 ° C., using a Merten rheometer manufactured by Toyo Seiki Seisakusho. For example, “Journal of Japanese Society of Rheology, Reference can be made to "Research on viscosity, Kiyoto Koyama, 174-180, Vol. 19, 1991". Although it does not restrict | limit especially about a strain rate, Usually, it measures at 0.01-5 / s from the restriction | limiting on a measuring apparatus.

Examples of such a propylene resin (B) include a high melt tension propylene resin having a long chain branch and a non-crosslinked high melt tension propylene resin.
The high melt tension propylene-based resin having a long chain branch has a branching index of less than 1, preferably less than 0.4 (lower limit is, for example, 0.2), and does not include a gel having strain hardening elongation viscosity. Preference is given to predominantly isotactic semicrystalline polypropylene. Such a high melt tension polypropylene resin can be produced, for example, by the method described in JP-A-62-1121704.
Here, the branching index quantifies the degree of long-chain branching and is defined by [η] sr / [η] Lin. Here, [η] sr is the intrinsic viscosity of branched polypropylene, and [η] Lin is the intrinsic viscosity of linear polypropylene having substantially the same weight average molecular weight.

Elongation viscosity is the resistance to elongation of a fluid or semi-fluid material. The strain hardening elongation viscosity is a characteristic showing a phenomenon that the elongation viscosity increases as the elongation amount increases. That is, it is a characteristic showing a phenomenon in which the elongational viscosity increases as long chain branching is introduced. By introducing long chain branching, the strain hardening elongation viscosity is exhibited. This elongational viscosity can be measured by an apparatus for measuring stress and strain of a sample in a molten state when subjected to tensile strain at a constant speed.
The high melt tension propylene-based resin having such a long chain branch can be appropriately selected from commercially available ones. Examples of commercially available products include “PF-814” sold by Sun Allomer Co., Ltd.
A high melt tension propylene resin having a long chain branch is produced by an electron beam cross-linking method, and therefore has a disadvantage that it is not suitable for recycling because of its structure. Therefore, a non-crosslinked high melt tension propylene resin is desirable.

The non-crosslinking type high melt tension propylene-based resin is composed of a propylene / α-olefin copolymer containing 50% by weight or more of propylene polymerized units. The olefin other than propylene copolymerized with propylene is not particularly limited, but an olefin having 2 to 12 carbon atoms is preferably used. Specific examples include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, 3-methyl-1-pentene, and the like. May be not only one but also two.
Specific examples of the propylene / α-olefin copolymer include propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-pentene copolymer, and propylene-1-hexene copolymer. , Propylene-1-octene copolymer, propylene-1-decene copolymer, propylene-4-methyl-1-pentene copolymer, and propylene-3-methyl-1-pentene copolymer. The propylene / α-olefin copolymer usually contains propylene polymerized units in an amount of 50% by weight or more, preferably 80% by weight or more, more preferably 85% by weight or more.

In particular, the non-crosslinking type high melt tension propylene resin contains the following components (a) and (b), and the component (b) is 0.01 to 20 parts by weight with respect to 100 parts by weight of the component (a). It is desirable that
(A) a propylene homopolymer or a propylene / α-olefin copolymer containing 50% by weight or more of a propylene homopolymer or an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 0.2 to 10 dl / g .
(B) An ethylene homopolymer or an ethylene / α-olefin copolymer containing 50% by weight or more of an ethylene polymer having an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 15 to 100 dl / g.

Component (a) Component (a) used as one component of a non-crosslinking type high melt tension propylene resin preferably has an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 0.2 to 10 dl / g. Yes, more preferably 0.5-8 dl / g, a propylene homopolymer or a propylene-olefin copolymer containing 50% by weight or more of propylene polymerized units.
When the intrinsic viscosity [η] of the component (a) is less than 0.2 dl / g, the foaming characteristics of the resulting composition deteriorate, and when it exceeds 10 dl / g, the fluidity of the obtained resin deteriorates.

The propylene-olefin copolymer used in the component (a) is not particularly limited as long as the intrinsic viscosity [η] is in the above range. For example, a propylene-based block copolymer or a propylene-based resin composition described below can be used. preferable.
That is, the propylene / olefin copolymer (a) comprises a propylene unit content of 99.4 to 100 mol%, a polymer component (A) consisting of propylene alone or a propylene / olefin random copolymer, and a propylene unit content. A propylene block copolymer or a propylene resin composition comprising a polymer component (B) comprising a propylene / olefin random copolymer in an amount of 35 to 60 mol%, wherein the polymer component (B) the intrinsic viscosity _{[eta] B} is 0.5~2.0dl / g, the ratio of the intrinsic viscosity _{[eta] a} intrinsic viscosity _{[eta] B} and the polymer component of the polymer component (B) (a) [ η] _B / [η] _A is 0.3 to 1.2, and this intrinsic viscosity ratio [η] _B / [η] _A , the polymer component (A), and the polymer component (B) the weight ratio _W a / _{W B} and the product ([eta] _B / [η] _A ) · (W _A / W _B ) is a propylene-based block copolymer or propylene-based resin composition having a ratio of 1.0 to 3.0.

Moreover, it is preferable that content of a polymer component (B) is 22 to 49 weight% of a propylene-type block copolymer or a propylene-type resin composition. If the content of the polymer component (B) is less than 22% by weight, the impact resistance tends to be insufficient, and if it exceeds 49% by weight, the rigidity and heat resistance are likely to be insufficient.
In addition, although it does not specifically limit as olefins other than propylene copolymerized with propylene, A C2-C12 olefin is used preferably. Specific examples include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, 3-methyl-1-pentene, and the like. May be not only one but also two. Specific examples of propylene and olefin copolymers having 2 to 12 carbon atoms include propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-pentene copolymer, propylene-1- Examples include hexene copolymer, propylene-1-octene copolymer, propylene-1-decene copolymer, propylene-4-methyl-1-pentene copolymer, and propylene-3-methyl-1-pentene copolymer. It is done. The propylene / α-olefin copolymer usually contains propylene polymerized units in an amount of 50% by weight or more, preferably 80% by weight or more, more preferably 85% by weight or more.

  In the said polymer component (A), propylene unit content is 99.4-100 mol%. If the propylene content is less than 99.4 mol%, the heat resistance tends to decrease. Moreover, in the said polymer component (B), propylene unit content is 35-60 mol%. The propylene content affects the impact resistance at low temperatures, and the lower the content, the better the impact resistance at low temperatures, but too little affects the dispersibility of the copolymer and crystalline polypropylene, The impact resistance tends to decrease.

Further, the polymer component (B) has an intrinsic viscosity [η] _B measured in tetralin at 135 ° C. of 0.5 to 2.0 dl / g, and the polymer component (A) measured under the same conditions. The intrinsic viscosity ratio [η] _B / [η] _A to the intrinsic viscosity [η] _A is preferably in the range of 0.3 to 1.2.
The intrinsic viscosity [η] _B of the polymer component (B) particularly affects the rigidity, and [η] _B / [η] _A affects the dispersibility of the polymer component (B) in the polymer component (A). Affect. If the intrinsic viscosity [η] _B is too large, the foamability is deteriorated. On the other hand, if [η] _B is too small, the impact resistance tends to decrease. On the other hand, if [η] _B / [η] _A is too small, the impact resistance at low temperatures is insufficient. On the other hand, if [η] _B / [η] _A is too large, the foaming properties are insufficient and the intended characteristics cannot be achieved.
In addition, when the polymer component (A) and the polymer component (B) are continuously produced to obtain a propylene-based block copolymer, the intrinsic viscosity [η] _B of the polymer component (B) cannot be directly measured. , the weight% _{W B} directly measurable polymer component (a) having an intrinsic viscosity _{[eta] a} propylene-based intrinsic viscosity of the whole block copolymer _{[eta] wHOLE} and the polymer component, (B), the following formula Ask for.
[Η] _B = {[η] _WHOLE− (1−W _B / 100) [η] _A } / (W _B / 100)
Here, continuously producing means that the polymer component (A) is produced in the first stage (first polymerization step), and then the polymer component (B) is continuously produced in the second stage (second stage). Polymerization step).

Further, the non-crosslinked type high melt strength propylene resins, polymer component on the weight of (A) and W _A, the weight ratio when the weight of the polymer component (B) was W _B (W A _/ W _B ) And the above-described intrinsic viscosity ratio ([η] _B / [η] _A ) of both components ([η] _B / [η] _A ) × (W _A / W _B ) is 1.0 to 3 It is important that it is in the range of 0.0, preferably 1.2 to 2.5.
That the product of the weight ratio and the intrinsic viscosity ratio is in the above range is that a plurality of domains composed of the polymer component (B) are dispersed in the state of extending in the flow direction of the composition during molding processing, Alternatively, the foam is an indispensable condition for showing a specific dispersion structure in which the dispersed domains are connected to other domains at least at one place, and the value is within the above numerical range. The impact resistance at a low temperature is improved.

The non-crosslinking type high melt tension propylene resin may be produced by any method as long as the above properties are satisfied. Of course, the polymer component (A) and the polymer component (B) produced separately are used. Even if it mixes using a mixing apparatus, a polymer component (A) may be manufactured, a polymer component (B) may be manufactured continuously, and a propylene-type block copolymer may be manufactured continuously. As the polymerization catalyst to be used, various catalysts such as a titanium trichloride catalyst capable of producing stereoregular polypropylene, a magnesium halide-supporting titanium-containing solid catalyst, or a metallocene catalyst can be used. More preferably, the manufacturing method shown below can be illustrated.
The constitutional feature of the continuous production method of the non-crosslinking type high melt tension propylene resin is a three-dimensional structure comprising a titanium-containing solid catalyst component (A) having a large particle size, an organoaluminum compound (B), and an organosilicon compound (C). In the presence of a regular catalyst, a polymer component (A) (hereinafter sometimes referred to as “crystalline polypropylene”) is produced in the gas phase in the first stage (hereinafter referred to as “crystalline polypropylene”), and the polymer component (A) is produced in the second stage. This is to continuously produce the coalescence component (B) (hereinafter sometimes referred to as “propylene / α-olefin copolymer”) (second polymerization step).

In the production method, the titanium-containing solid catalyst component (A) is an inorganic carrier such as a magnesium compound, silica compound or alumina, or an organic carrier such as polystyrene, and a titanium compound is supported on the carrier, as necessary. For example, any known compounds obtained by reacting an electron donating compound such as ethers such as 2-methyl-2-isobutyl-1,3-dimethoxypropane and esters such as di-n-butyl phthalate and diisobutyl phthalate may be used. Even things can be used.
For example, spraying a magnesium compound-alcohol solution, partially drying the solid component, and then treating the partially dried solid component with an electron donating compound such as titanium halide and di-n-butyl phthalate A solid catalyst component (Japanese Patent Laid-Open No. 3-119003), a magnesium compound dissolved in tetrahydrofuran / alcohol / electron donor, and precipitated as TiCl ₄ alone or in combination with the electron donor are converted to titanium halide and the above Examples thereof include a titanium-containing solid catalyst component (JP-A-4-103604) obtained by treatment with an electron donating compound.

The titanium-containing catalyst component (A) has an average particle diameter of 25 to 300 μm, preferably 30 to 150 μm. If the average particle diameter of the titanium-containing catalyst component (A) is less than 25 μm, the fluidity of the powdery polypropylene composition produced, that is, the powder fluidity is significantly impaired, and the polymer wall is used for the wall of the polymerization vessel, the stirring blade, etc. There are cases where the stable operation is greatly hindered, for example, the contamination in the polymerization system due to the adhesion of the polypropylene-based composition and the conveyance of the powder discharged from the polymerization vessel become difficult.
Further, the titanium-containing catalyst component (A) preferably has a normal distribution with a uniformity of 2.0 or less. When the degree of uniformity exceeds 2.0, the powder fluidity of the powdery polypropylene composition obtained may deteriorate and continuous stable operation may be difficult.

The organoaluminum compound (B) has a general formula of R ¹ _m AlX _3-m (wherein R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, X represents a halogen atom, and m is 3 ≧ m ≧ An organoaluminum compound (B) represented by a positive number of 1.5 can be used. Specifically, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, tri-i-butylaluminum, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum sesquichloride, di-n- Examples thereof include propylaluminum monochloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum iodide, ethoxydiethylaluminum, and preferably triethylaluminum is used.
These organoaluminum compounds can be used alone or as a mixture of two or more.

The organosilicon compound (C) is represented by the general formula R ² _X R ³ _Y Si (OR ⁴ ) _Z (wherein R ² and R ⁴ are hydrocarbon groups, and R ³ is a hydrocarbon group or a hydrocarbon containing a hetero atom. An organic silicon compound represented by 0 ≦ X ≦ 2, 1 ≦ Y ≦ 3, 1 ≦ Z ≦ 3, and X + Y + Z = 4 is used. Specifically, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, phenylmethyldimethoxysilane, t-butyltrimethoxysilane, t-butyltriethoxysilane, phenyltriethoxysilane, methylethyldimethoxysilane , Methylphenyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, di-t-butyldimethoxysilane, diphenyldimethoxysilane, trimethylmethoxysilane, cyclohexylmethyldimethoxysilane, trimethylethoxysilane, etc. Can be mentioned. Preferably, diisobutyldimethoxysilane, diisopropyldimethoxysilane, di-t-butyldimethoxysilane, cyclohexylmethyldimethoxysilane and diphenyldimethoxysilane are used.
These organosilicon compounds can be used alone or as a mixture of two or more.

The titanium-containing solid catalyst component (A), the organoaluminum compound (B), and a stereoregular catalyst in combination with an organosilicon compound (C) as necessary are used for propylene polymerization in the first polymerization step. The solid catalyst (A) is preferably used as a catalyst that has been pre-activated by reacting an α-olefin in advance.
In the preactivation treatment of the titanium-containing solid catalyst component (A), the amount of the organoaluminum compound (B ′) used is not particularly limited, but is usually 1 mol of titanium atom in the titanium-containing solid catalyst component. It is used in the range of 0.1 to 40 mol, preferably 0.3 to 20 mol, and the α-olefin is 0 per gram of the titanium-containing solid catalyst component (A) at 10 to 80 ° C. for 10 minutes to 48 hours. .1 to 100 grams, preferably 0.5 to 50 grams are reacted.
In the preactivation treatment, the organosilicon compound (C ′) may be used in the range of 0.01 to 10 mol, preferably 0.05 to 5 mol, per 1 mol of the organoaluminum compound.

Examples of the organoaluminum (B ′) used in the above preactivation treatment include the exemplified organoaluminum (B) used in the main polymerization. The organoaluminum compound (B ′) may be the same as or different from the organoaluminum compound (B) used in the main polymerization, but preferably triethylaluminum is used.
Moreover, as an organosilicon compound (C ') used as needed for a preactivation process, the same kind as the organosilicon compound (C) illustrated above can be mentioned. The organosilicon compound (C ′) may be the same as or different from the organosilicon compound (C) used in the main polymerization, and is preferably diisobutyldimethoxysilane, diisopropyldimethoxysilane, di-t. -Use butyldimethoxysilane, cyclohexylmethyldimethoxysilane and diphenyldimethoxysilane.

Examples of the α-olefin used for the preactivation treatment of the titanium-containing solid catalyst component (A) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, 4-methyl-1-pentene, 3-methyl-1-pentene and the like. These olefins may contain not only a single olefin but also one or a mixture of two or more other olefins. In addition, a molecular weight regulator such as hydrogen can be used in combination in order to regulate the molecular weight of the polymer during the polymerization.
The inert solvent used for the preactivation treatment of the titanium-containing solid catalyst component (A) is a liquid saturated hydrocarbon such as hexane, heptane, octane, decane, dodecane, and liquid paraffin, or silicon oil having a dimethylpolysiloxane structure. It is an inert solvent that does not significantly affect the polymerization reaction. These inert solvents may be either one kind of single solvent or two or more kinds of mixed solvents. When these inert solvents are used, it is preferable to use them after removing impurities such as moisture and sulfur compounds which adversely affect the polymerization.

A first polymerization step for producing crystalline polypropylene by polymerizing propylene or the propylene and a small amount of α-olefin in the gas phase in the presence of the preactivated titanium-containing solid catalyst component (A); Next, a second polymerization step is carried out continuously in which propylene / α-olefin copolymer is produced by copolymerizing propylene and α-olefin in the presence of the crystalline polypropylene.
The first polymerization step is not limited to the gas phase polymerization method, and a slurry polymerization method or a bulk polymerization method may be adopted, but the second polymerization step continuous thereto is preferably a gas phase polymerization method. Therefore, it is preferable that the first polymerization step also employs a gas phase polymerization method. When a slurry polymerization method or a bulk polymerization method is employed as the second polymerization step, the resulting copolymer is eluted in the solution, making it difficult to continue stable operation.

  Polymerization conditions for crystalline polypropylene differ depending on the polymerization mode. In the case of gas phase polymerization, a titanium-containing solid catalyst component (A) pretreated by mixing and stirring a certain amount of powdered polypropylene composition. In the presence of a stereoregular catalyst comprising an organoaluminum component (B) and an organosilicon compound (C), a polymerization temperature of 20 to 120 ° C., preferably 40 to 100 ° C., a polymerization pressure of atmospheric pressure to 9.9 MPa, preferably 0 Propylene or the propylene and a small amount of α-olefin are supplied and polymerized under a condition of .59 to 5.0 MPa to produce crystalline polypropylene.

The use ratio of the organoaluminum compound (B) and the titanium-containing solid catalyst component (A) is Al / Ti = 1 to 500 (molar ratio), preferably 10 to 300. In this case, the number of moles of the titanium-containing solid catalyst component (A) substantially refers to the number of Ti gram atoms in the titanium-containing solid catalyst component (A). The usage rate of the organosilicon compound (C) and the organoaluminum component (B) is B / C = 1 to 10 (molar ratio), preferably 1.5 to 8. When the molar ratio of (B) / (C) is excessive, the crystallinity of the crystalline polypropylene is lowered, and the rigidity of the resulting polypropylene composition is insufficient. On the other hand, when the B / C molar ratio is too small, the polymerization activity is remarkably lowered and the productivity is lowered.
The molecular weight of the crystalline polypropylene can be adjusted by using a molecular weight regulator such as hydrogen during the polymerization, and the intrinsic viscosity of the crystalline polypropylene is performed so as to satisfy the requirements of the present invention. After polymerizing the crystalline polypropylene, a part of the produced powdery polymer is extracted and used for measurement of intrinsic viscosity, melt flow rate, and polymerization yield per unit weight of the catalyst.

  Subsequent to the polymerization in the first polymerization step, the polymerization temperature is 20 to 120 ° C., preferably 40 to 100 ° C., the polymerization pressure is atmospheric pressure to 9.9 MPa, preferably 0.59 to 5.0 MPa. A second polymerization step is carried out in which a mixed monomer with olefin is copolymerized to produce a propylene / α-olefin copolymer. The α-olefin content in the propylene / α-olefin copolymer is controlled by controlling the gas molar ratio of the α-olefin monomer and the propylene monomer in the comonomer gas so that the propylene content in the copolymer is 35 to 60 mol%. Adjust so that

  On the other hand, the weight of the propylene / α-olefin copolymer relative to the weight of the crystalline polypropylene is controlled by adjusting the polymerization time or using a polymerization activity regulator of a catalyst such as carbon monoxide or hydrogen sulfide. The weight of the polymer is adjusted to 22 to 44% by weight. Further, the molecular weight of the propylene / α-olefin copolymer is copolymerized with a molecular weight regulator such as hydrogen so that the intrinsic viscosity of the propylene / α-olefin copolymer satisfies the requirements of the polypropylene composition used in the present invention. Sometimes adjusted in addition. Moreover, the supply method of hydrogen is supplied so that the polypropylene composition obtained may satisfy the requirements of the present invention. As the polymerization method, any of batch type, semi-continuous type or continuous type can be adopted, but industrially preferred is a continuous polymerization type.

  After completion of the second polymerization step, the monomer can be removed from the polymerization system to obtain a powdery polypropylene composition. A part of the obtained polypropylene composition is subjected to measurement of intrinsic viscosity, measurement of α-olefin content, and measurement of polymerization yield per unit weight of catalyst.

Component (b) The component (b) used in the non-crosslinking type high melt tension propylene resin has an intrinsic viscosity [η] measured in tetralin at 135 ° C. of preferably 15 to 100 dl / g, more preferably An ethylene homopolymer or an ethylene / α-olefin copolymer containing 50% by weight or more of an ethylene polymerized unit of 17 to 50 dl / g.
If the intrinsic viscosity [η] of the component (b) is less than 15 dl / g, the melt tension and crystallization temperature of the resulting composition will be insufficient. On the other hand, exceeding 100 dl / g is not preferable from the viewpoint of production efficiency.
In addition, although it does not specifically limit as alpha-olefins other than ethylene copolymerized with ethylene, C3-C12 olefin is used preferably. Specific examples include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, 3-methyl-1-pentene, and the like. May be not only one but also two.

  When the composition containing the component (a) and the component (b) is used as the non-crosslinking type high melt tension propylene resin, the amount of the component (b) in the composition is 100 parts by weight of the component (a). On the other hand, 0.01-20 weight part is preferable, More preferably, it is 0.02-10 weight part. When the amount of the component (b) is less than 0.01 parts by weight, the effect of improving the melt tension of the obtained resin is small, and when it exceeds 20 parts by weight, the effect is saturated and the homogeneity of the resulting foam is impaired. Therefore, it is not preferable.

  The compounding quantity of the propylene-type resin (B) contained in the resin mixture used by this invention is 70 to 5 weight%, Preferably it is 50 to 10 weight%, More preferably, it is 40 to 20 weight%. If it is less than 5% by weight, it becomes difficult to make the foamed cells fine during molding. If it exceeds 70%, the spreadability at the time of molding deteriorates, and film breakage occurs.

Foaming agent The foaming agent used in the present invention is a thermal decomposition type chemical foaming agent, and any known one may be used, and any thermal decomposition type chemical foaming agent of an inorganic compound or an organic compound may be used.
Specific examples of the inorganic compound include sodium bicarbonate, ammonium carbonate, ammonium nitrite and the like. On the other hand, specific examples of the organic compound include azide compounds such as azodicarbonamide, azobisformamide, isobutyronitrile, diazoaminobenzene, N, N′-dinitrosopentatetramine, N, N′-dimethyl-dinitroterephthalate. Illustrative are nitroso compounds such as amides. In addition, this foaming agent may be used independently and may be used together 2 or more types.

  In this invention, the compounding quantity of a foaming agent is 0.05-3.0 weight part with respect to 100 weight part of said resin mixtures, Preferably it is 0.3-2.0 weight part, More preferably, 0.4- 1.5 parts by weight. If it is significantly higher than 3.0% by weight, it will be excessively foamed, and it will be difficult to make the foamed cells uniform and fine.

Other components In the foamed resin composition for air-cooled inflation of the present invention, in addition to the resin mixture and the foaming agent, known antioxidants, neutralizers, light stabilizers, ultraviolet absorbers, and the like, which are usually used for polyolefins, Various additives such as an inorganic filler, an antiblocking agent, a lubricant, an antistatic agent, a metal deactivator, and a pigment can be blended within a range that does not impair the object of the present invention.
Examples of antioxidants include phenolic antioxidants, phosphite antioxidants, and thio antioxidants, and examples of neutralizing agents include higher fatty acid salts such as calcium stearate and zinc stearate. Examples of stabilizers and ultraviolet absorbers include hindered amines, nickel complex compounds, benzotriazoles, and benzophenones.

Examples of inorganic fillers and antiblocking agents include calcium carbonate, silica, hydrotalcite, zeolite, aluminum silicate, magnesium silicate, and examples of lubricants include higher fatty acid amides such as stearic acid amide. .
Furthermore, examples of the antistatic agent include fatty acid partial esters such as glycerin fatty acid monoester, and examples of the metal deactivator include triazines, phosphones, epoxies, triazoles, hydrazides, and oxamides. .
The compounding quantity of these additives is 0.0001 to 3 weight% with respect to a general polypropylene polymer, Preferably it is 0.001 to 1 weight%. Furthermore, other resin can be mix | blended in the range which does not impair the effect of this invention remarkably.

Air-cooled inflation molding The foamed resin composition for air-cooled inflation of the present invention is generally formed into a foam film having excellent appearance with uniform fine foam cells by general air-cooled inflation molding that can be produced using a polypropylene resin composition. It is possible to mold.
The air-cooled inflation molding method is widely used in the production of polypropylene resin films, and the raw material is melted by an extruder, the molten resin is extruded into a tube shape through an annular die, and is nipped by a pinch roll. Enclose the gas inside the tube through the hole provided inside the annular die, or circulate the internal gas while keeping the volume of the gas inside the tube constant (the shape of the bubble is constant), and the size according to the product size While blowing up, air supplied from a blower or the like is blown from the air ring to the outer surface of the melting tube to be cooled and solidified to form bubbles and taken up by a take-up machine.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited by these Examples. In the examples and comparative examples, the foamed resin composition for air-cooled inflation and the air-cooled inflation foam film were measured and evaluated according to the following evaluation methods.

1. Measurement method (1) MFR: Measured according to JIS K7210 at a heating temperature of 230 ° C. and a load of 21.2 N.
(2) Melt tension: Using a melt tension type 2 manufactured by Toyo Seiki Seisakusho Co., Ltd., a resin composition heated and melted at 190 ° C. was extruded from an orifice having a diameter of 2.095 mm and a length of 40 mm at a speed of 20 mm / min. The value when the value was stabilized was taken as the melt tension. (Unit: cN).
(3) Foamed cell diameter: Using a stereo microscope (Nikon: SMZ-1000-2 type), photographed from the upper surface of the film obtained by molding at a magnification of 8 times, and randomly created 10 foam cells. The cell diameters in the MD direction and the TD direction were measured.
(4) Foaming ratio: The weight of the foamed film at a size of 10 cm × 10 cm was measured, and the ratio was determined by the following calculation formula.
Foaming ratio ­ = Unfoamed film or sheet weight / foamed film or sheet weight (5) Appearance x: Large foam cell is not conspicuous ○: Good without large foam cell

2. Materials used Propylene resin (A)
1) Propylene resin (PP-1): a propylene resin within the scope of the present invention obtained by the following Production Example 1. (MFR is 2 g / 10 min, molecular weight distribution (Mw / Mn) is 2.6, and (T ₉₀ -T ₄₀ ) is 3 ° C.)

(Production Example 1)
(I) Synthesis of catalyst component (A) Synthesis of (r) -dichloro {1,1-dimethylsilylenebis [2-methyl-4 (4-chlorophenyl) -4H-azurenyl]} zirconium is disclosed in JP-A-11-240909. It was synthesized by the method described in the publication number.

(Ii) Preparation of catalyst component (B) Preparation of ion exchange layered silicate Into a glass separable flask equipped with a 10 liter stirring blade, 3.75 liters of distilled water, followed by concentrated sulfuric acid (96%). 5 kg was added slowly. At 50 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle size = 25 μm, particle size distribution = 10 μm to 60 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, and after reslurry, it was filtered. This washing operation was performed until the pH of the washing liquid (filtrate) exceeded 3.5.
The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 705 g. The composition (molar) ratio of the obtained ion-exchanged layered silicate was Al / Si = 0.129, Mg / Si = 0.018, Fe / Si = 0.133.

Further, 1.72 liters of distilled water and then lithium sulfate monohydrate (700 g) were added to a glass separable flask equipped with a 10 liter stirring blade to form a solution, and then the ion exchange property obtained above. Layered silicate was added. The slurry was stirred at room temperature for 240 minutes. This slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake, and after reslurry, it was filtered. This operation was repeated three times.
The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 695 g. The composition (molar) ratio of the obtained ion-exchange layered silicate was Al / Si = 0.127, Mg / Si = 0.020, Fe / Si = 0.133, Li / Si = 0.018. there were.
The silicate previously chemically treated was further dried by a kiln dryer. The specifications and conditions of the dryer are as follows.
Rotating cylinder: cylindrical shape, inner diameter 50 mm, humidification zone 550 mm (electric furnace), rotation speed with lifting blade: 2 rpm, tilt angle: 20/520, silicate feed rate: 2.5 g / min, gas flow rate: nitrogen, 96 liters / hour, countercurrent drying temperature: 200 ° C. (powder temperature)

(Iii) Preparation of catalyst Mixture of 0.74 liters of heptane (hereinafter referred to as mixed heptane) containing 0.20 kg of dry silicate obtained above and toluene in a metal reactor equipped with a stirrer having an internal volume of 13 liters Then, 1.26 liters of a heptane solution of trinormal octyl aluminum (0.04M) was added, and the system temperature was maintained at 25 ° C. After 1 hour of reaction, the mixture was thoroughly washed with mixed heptane to prepare a silicate slurry at 2.0 liters. In parallel, 2.18 g (3.30 mmol) of (r) -dichloro {1,1-dimethylsilylenebis [2-methyl-4 (4-chlorophenyl) -4H-azurenyl]} zirconium synthesized earlier in toluene Was added to the silicate slurry, and the mixture was reacted for 1 hour at room temperature. After stirring for 1 hour, mixed heptane was added. Was adjusted to 5.0 liters. Subsequently, when the internal temperature was raised to 40 ° C. and stabilized, propylene was supplied at a rate of 100 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, and the catalyst was thoroughly washed with mixed heptane. Subsequently, 0.17 L of a heptane solution of triisobutylaluminum (0.71 M / L) was added, followed by drying at 45 ° C. under reduced pressure. By this operation, 0.60 kg of a dried prepolymerized catalyst was obtained.

(Iv) Polymerization After the inside of a stirring autoclave having an internal volume of 200 liters was sufficiently substituted with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced. To this, 500 ml (0.12 mol) of a triisobutylaluminum / n-heptane solution, 2.03 kg of ethylene and 1.1 NL of hydrogen were added, and the internal temperature was maintained at 30 ° C. Next, 1.2 g of the prepolymerized catalyst component was injected with argon to initiate polymerization, and the temperature was raised to 70 ° C. over 30 minutes, and the temperature was maintained for 1 hour. During this time, hydrogen was introduced at a constant speed of 0.07 g / hr. Here, 100 ml of ethanol was added to stop the reaction. The residual gas was purged to obtain a propylene / ethylene random copolymer (ethylene 3.5 wt%, propylene 96.5 wt%).

(V) Granulation Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4 ′) which is a phenolic antioxidant with respect to 100 parts by weight of the propylene / ethylene random copolymer. -Hydroxyphenyl) propionate] methane (trade name: IRGANOX 1010, manufactured by Ciba Specialty Chemicals) 0.05 parts by weight, tris (2,4-di-t-butylphenyl) phos, a phosphite antioxidant Fight (trade name: IRGAFOS 168, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.05 parts by weight, and calcium stearate as a neutralizing agent (trade name: calcium stearate, manufactured by Nippon Oil & Fats Co., Ltd.) 0.05 weight After mixing for 3 minutes at room temperature with a high-speed stirring mixer (Henschel mixer, trade name), Melt kneaded to obtain pellets (polypropylene resin PP-1).

2) NLE3300 (Propylene / ethylene / butene random copolymer manufactured by Nippon Polypro Co., Ltd. obtained using a Ziegler catalyst): Propylene-based resin outside the scope of the present invention MFR 3 g / 10 min, molecular weight distribution (Mw / Mn) but _4.9, (T 90 _{-T 40)} is 12 ° C.
3) WFX4 (Propylene / ethylene random copolymer manufactured by Nippon Polypro Co., Ltd. obtained using a metallocene catalyst): Propylene resin MFR outside the scope of the present invention was 7 g / 10 min, and molecular weight distribution (Mw / Mn) was 2. .6, (T ₉₀ -T ₄₀ ) is 3 ° C.
5) EA9 (Propylene homopolymer manufactured by Nippon Polypro Co., Ltd. obtained using Ziegler catalyst): Propylene resin MFR outside the scope of the present invention is 0.7 g / 10 min, and molecular weight distribution (Mw / Mn) is 5. 0.0, (T ₉₀ -T ₄₀ ) is 4 ° C.
6) BX8HR (Nippon Polypro's block PP obtained using a Ziegler catalyst): Propylene resin MFR outside the scope of the present invention is 1 g / 10 min, melting peak temperature (Tm) is 162 ° C., molecular weight distribution (Mw) / Mn) is 7.7, and (T ₉₀ -T ₄₀ ) is 105 ° C.

Propylene resin (B)
1) 1) Propylene resin (PP-2): Propylene resin within the scope of the present invention obtained by Production Example 2 below

(Production Example 2)
(I) Preparation of transition metal compound catalyst component In a stainless steel reactor equipped with a stirrer, 37.5 liters of decane, 7.14 kg of anhydrous magnesium chloride and 35.1 liters of 2-ethyl-1-hexanol were mixed and stirred. The mixture was heated at 140 ° C. for 4 hours to obtain a uniform solution. 1.67 kg of phthalic anhydride was added to the homogeneous solution, and further stirred and mixed at 130 ° C. for 1 hour to dissolve the phthalic anhydride in the homogeneous solution.
The obtained homogeneous solution was cooled to room temperature (23 ° C.), and then the entire amount of this homogeneous solution was dropped into 200 liters of titanium tetrachloride maintained at −20 ° C. over 3 hours. After dropping, the temperature was raised to 110 ° C. over 4 hours, and when it reached 110 ° C., 5.03 liters of di-i-butyl phthalate was added, and the reaction was carried out by stirring and holding at 110 ° C. for 2 hours. After completion of the reaction, the solid part was collected by hot filtration, and the solid part was resuspended in 275 liters of titanium tetrachloride, and then the reaction was continued again at 110 ° C. for 2 hours.
After completion of the reaction, the solid part was again collected by hot filtration and sufficiently washed with n-hexane until no free titanium was detected in the washing solution. Subsequently, the solvent was separated by filtration, and the solid part was dried under reduced pressure to obtain a titanium-containing supported catalyst component (transition metal compound catalyst component) containing 2.4% by weight of titanium.

(Ii) Preparation of pre-activated catalyst After replacing a 30 liter stainless steel reactor with inclined blades with nitrogen gas, 18 g of n-hexane, 60 mmol of triethylaluminum, and 150 g of titanium-containing supported catalyst component prepared in the previous section (75.16 mmol in terms of titanium atom) was added, and then 500 g of propylene was supplied, and prepolymerization was performed at −2 ° C. for 40 minutes.
Separately, as a result of analyzing the polymer produced after the prepolymerization performed under the same conditions, 3.0 g of polypropylene was produced per 1 g of the titanium-containing supported catalyst component, and the solid viscosity [ηA] of this polypropylene was 2.80 dl / g. Met.
After completion of the reaction time, unreacted propylene is discharged out of the reactor, the gas phase of the reactor is replaced with nitrogen once, and the pressure in the reactor is maintained while maintaining the temperature in the reactor at 0 ° C. The ethylene was continuously fed to the reactor for 6 hours so as to maintain the pressure at 0.59 MPa, and prepolymerization was performed. Separately, as a result of analyzing the polymer produced after the pre-activation polymerization performed under the same conditions, 73.3 g of the polymer is present per 1 g of the titanium-containing supported catalyst component, and the intrinsic viscosity [ηT] of the polymer is 29.7 dl. / G.
The amount of polyethylene per gram of titanium-containing supported catalyst component (WB) produced by preactivation polymerization with ethylene is the amount of polymer produced per gram of titanium-containing catalyst component after preactivation treatment (WT) and the amount of polyethylene after prepolymerization. It is calculated | required by following Formula as a difference with the polypropylene production amount per 1g of titanium containing type catalyst components (WA).
[ΗB] = ([ηT] × WT− [ηA] × WA) / (WT−WA)
After completion of the reaction time, unreacted ethylene was discharged out of the reactor, and the gas phase part of the reactor was purged with nitrogen once to obtain a pre-activated catalyst slurry for producing a propylene polymer composition. Separately, the amount of polyethylene produced by the preactivation polymerization with ethylene was calculated from the above formula using the data of the prepolymerization with propylene and the prepolymerization activation polymerization with ethylene performed under the same conditions. 70.3 g per gram, the intrinsic viscosity of the polyethylene was 30.9 dl / g.
As a result, an ethylene / α-olefin copolymer (b) made of an ethylene homopolymer having an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 30.9 dl / g was obtained.

(Iii) Production of Propylene / Olefin Copolymer (a) A continuous horizontal gas phase polymerization vessel (length / diameter = 3.7) equipped with a stirrer with an internal volume of 110 liters purged with nitrogen was charged with the catalyst component. 25 kg of polypropylene powder is introduced as a dispersion medium, and the preactivated catalyst slurry is 0.62 g / h as a titanium-containing supported catalyst component, or triethylaluminum and diisopropyldimethoxysilane are added to the titanium atoms in the titanium-containing supported catalyst component. Were continuously fed so that the molar ratios were 90 and 15, respectively.
Further, under the condition of a polymerization temperature of 70 ° C., hydrogen is added so that the ratio of hydrogen concentration in the polymerization vessel to polypropylene concentration is 0.0055, and propylene is maintained so that the pressure in the polymerization vessel is maintained at 2.15 MPa. The mixture was fed into the polymerization vessel and propylene gas phase polymerization was carried out continuously for 150 hours. During the polymerization, the polymer was withdrawn from the polymerization vessel at a rate of 11 kg / h so that the retained level of the polymer in the polymerization vessel was maintained at 60% by volume. The extracted polymer was subjected to contact treatment with nitrogen gas containing 5% by volume of water vapor at 100 ° C. for 30 minutes to obtain a polymer having an intrinsic viscosity of 1.98 dl / g. The obtained polymer was a propylene-based resin (B) having a content of 0.90% by weight of the ethylene / α-olefin copolymer (b) produced by the preactivation treatment, and the propylene / olefin copolymer (a ) Was 1.86 dl / g.
100 parts by weight of this propylene-based resin (B), 0.1 part by weight of 2,6-di-t-butyl-p-cresol, and 0.1 part by weight of calcium stearate are mixed, and the mixture is mixed with a screw diameter of 40 mm. Granulation was performed at 230 ° C. using an extruder to obtain a pellet-shaped polypropylene resin (PP-2). The obtained pellet had an MFR of 2 g / min, a melt tension of 21 cN, and had strain hardening properties.
2) PF814: high melt tension propylene resin having a long chain branch made by Sun Allomer Co., Ltd .: propylene resin within the scope of the present invention MFR 3 g / 10 min, melt tension 25 cN, strain hardening 3) FY6H ( Polypropylene resin manufactured by Nippon Polypro Co., Ltd.): propylene resin outside the scope of the present invention MFR 1.7 g / 10 min, melt tension 4 cN, no strain hardening

Foaming agent 1) EE275F (manufactured by Eiwa Kasei Co., Ltd., trade name: Polyslen EE275F): Inorganic foaming agent

Example 1
Dry blending is performed in a pellet blender using a foamed resin composition for air-cooled inflation in which 2 parts by weight of EE275F is blended with 100 parts by weight of a resin mixture comprising 60% by weight of PP-1 and 40% by weight of PP-2. Using an air-cooled inflation molding machine (extruder: 50 mmφ, die: 200 mmφ, spiral die, lip 0.7 mm), an air-cooled inflation film of 200 μm was obtained under the following molding conditions. The results are shown in Table 2.
Temperature setting: C1 / C2 / C3 / A / D = 150/220/185/185/185 ° C.
・ Blow ratio: 1.5
・ Pickup speed: 3.3 m / min

(Example 2)
An air-cooled inflation foamed film was obtained under the same conditions as in Example 1 except that PP-1 was 80% by weight and PP-2 was 20% by weight. The results are shown in Table 2.

(Example 3)
An air-cooled inflation foamed film was obtained under the same conditions as in Example 1 except that PP-2 was replaced with PF814. The results are shown in Table 2.

Example 4
4 parts by weight of EE275F is used for 100 parts by weight of the resin mixture comprising 60% by weight of PP-1 and 40% by weight of PP-2 for the intermediate layer, using WFX4 for the outer layer and the innermost layer constituting both surfaces of the intermediate layer. Using the blended foamed resin composition for air-cooled inflation, dry blending is performed with a pellet blender, and air-cooled inflation molding machine (extruder: outer layer, innermost layer 40 mmφ, intermediate layer 50 mmφ, die: 200 mmφ, spiral die, lip 0.7 mm) Was used to obtain an air-cooled inflation foam film having an outer layer / intermediate layer / innermost layer thickness of 25/200/25 μm under the following conditions. The results are shown in Table 3.
Temperature setting: C1 / C2 / C3 / A / D = 150/220/185/185/185 ° C.
・ Blow ratio: 1.5
・ Pickup speed: 3.3 m / min

(Comparative Example 1)
An attempt was made to obtain an air-cooled inflation foam film under the same conditions as in Example 1 except that PP-1 was not used. However, film breakage due to poor spreadability occurred, and an air-cooled inflation foam film could not be obtained. . The results are shown in Table 2.

(Comparative Example 2)
An attempt was made to obtain an air-cooled inflation foam film under the same conditions as in Example 1 except that PP-2 was not used. However, film breakage due to bubble breakage occurred, and an air-cooled inflation foam film could not be obtained. The results are shown in Table 2.

(Comparative Example 3)
An air-cooled inflation foamed film was obtained under the same conditions as in Example 1 except that PP-1 was replaced with NLE3300. The results are shown in Table 2.

(Comparative Example 4)
An air-cooled inflation foamed film was obtained under the same conditions as in Example 1 except that PP-1 was replaced with EA9. The results are shown in Table 2.

(Comparative Example 5)
An air-cooled inflation foamed film was obtained under the same conditions as in Example 1 except that PP-1 was replaced with WFX4. The results are shown in Table 2.

(Comparative Example 6)
An attempt was made to obtain an air-cooled inflation foam film under the same conditions as in Example 1 except that PP-2 was replaced with FY6H. However, film breakage due to bubble breakage occurred, and an air-cooled inflation foam film could not be obtained. . The results are shown in Table 2.

(Comparative Example 7)
An attempt was made to obtain an air-cooled inflation foam film under the same conditions as in Example 1 except that PP-1 was replaced with BX8HR and PP-2 was replaced with PF814, but bubbles were not stable, and an air-cooled inflation foam film was obtained. I couldn't. The results are shown in Table 2.

As is clear from Table 2, the air-cooled inflation foamed films obtained in Examples 1 to 3 are difficult to rapidly cool because the foamed resin composition for air-cooled inflation used is within the scope of the present invention. Also in the air-cooled inflation method, the moldability was good and the foamed cells were very fine and uniform, so that the appearance was extremely excellent.
Further, as is clear from Table 3, the multilayer air-cooled blown film obtained in Example 4 is covered with non-foamed layers on both sides, so that the foam cells are further finer than the single-layer air-cooled blown film. And the expansion ratio can be improved.

  On the other hand, as is clear from Table 2, in Comparative Examples 1, 7, and 6, since the foamed resin composition for air-cooled inflation used is outside the scope of the present invention, Comparative Examples 1, 2, 6 and 7 The air-cooled inflation foam film could not be molded, and the air-cooled inflation foam films obtained in Comparative Examples 3 to 5 were very inferior in appearance because the foamed cells were large and non-uniform.

  The air-cooled inflation foamed film obtained by the foamed resin composition for air-cooled inflation of the present invention has good moldability even in the air-cooled inflation method in which it is difficult to obtain a foamed film because it is difficult to rapidly cool, and the foamed cells are very fine and uniform. Since the appearance is also extremely excellent, the printability is good and it is extremely suitable for packaging applications. In addition, the air-cooled inflation foamed resin composition of the present invention contributes to the development of the industrial field of polymer material development, and as a molding technique for air-cooled inflation foam film, in the plastic molding industry, a new molding technique has been developed. It shows the possibility. In addition, the foamed foam film is lightweight without compromising the physical and mechanical properties of the polypropylene resin, so it can be used in automobiles, architectural interior materials, packaging materials, lightweight containers, lightweight bottles, shock absorbing materials, vibration absorbing materials, It has industrial applicability to serve existing or new applications such as light reflection, shielding materials, lighting fixtures, heat insulating materials, decorative materials, etc. In addition, the foamed sheet can be used as a secondary processing film by conventional pressurization, vacuum, and blow molding, and contributes to the development of the processing industry.

Claims (4)

  30 to 95% by weight of a propylene-based resin (A) having an MFR of 0.5 to 4 g / 10 min polymerized using a metallocene catalyst, an MFR of 0.1 to 20 g / 10 min, and a melt tension (230, caliber 2 mm) of 1 The foaming agent is added in an amount of 0.05 to 6 to 100 parts by weight of a resin mixture obtained by blending 70 to 5% by weight of a propylene-based resin (B) that is 0.0 to 50 cN and has strain-hardening properties under elongation flow. A foamed resin composition for air-cooled inflation, comprising 0.0 part by weight. The foamed resin composition for air-cooled inflation according to claim 1, wherein the propylene-based resin (A) satisfies the following characteristics (i) to (iv).
(I) MFR is 0.5 to 3.5 g / 10 min,
(Ii) the molecular weight distribution (Mw / Mn) measured by GPC method is 1.5-4,
(Iii) In the elution curve obtained by temperature rising elution fractionation (TREF), it is the difference between the temperature (T ₄₀ ) extracted by 40% by weight and the temperature (T ₉₀ ) extracted by 90% by weight (T ₉₀ -T _40). ) Is 6 ° C. or less. The propylene-based resin (B) contains the following components (a) and (b), and the resin composition (b) is 0.01 to 20 parts by weight with respect to 100 parts by weight of the component (a). The foamed resin composition for air-cooled inflation according to claim 1 or 2.
(A) a propylene homopolymer or a propylene / α-olefin copolymer containing 50% by weight or more of a propylene homopolymer or an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 0.2 to 10 dl / g .
(B) An ethylene homopolymer or an ethylene / α-olefin copolymer containing 50% by weight or more of an ethylene polymer having an intrinsic viscosity [η] measured in tetralin at 135 ° C. of 15 to 100 dl / g.   An air-cooled inflation foamed film obtained using the foamed resin composition for air-cooled inflation according to any one of claims 1 to 3.