JP2002212359A - Resin composition for heat shrinkable polypropylene shrink label and film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both a composition for a heat shrinkable polypropylene shrinkage label having an ultralow specific gravity and improved heat shrinkage percentage and a film using the resin composition. SOLUTION: This resin composition for the heat shrinkable polypropylene shrinkage label comprises >95 and <100 wt.% of a crystalline propylene-α-olefin random copolymer consisting essentially of propylene and having specific physical properties and <5 wt.% of an alicyclic hydrocarbon resin having >=110 deg.C softening point temperature. The film uses the resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for heat-shrinkable polypropylene shrink label and a film using the same, and more particularly, to a heat-shrinkable polypropylene shrink having improved heat shrinkage, especially low-temperature shrinkage. The present invention relates to a label resin composition and a film using the same.

[0002]

2. Description of the Related Art In recent years, the purpose of packaging articles is to improve the appearance, to prevent the contents from being directly impacted, to tightly package them, to protect glass bottles or plastic bottles, and to label products that combine the display of goods. Shrink labels are widely used. As plastic materials used for these purposes, polyvinyl chloride, polystyrene, polyethylene terephthalate (PET), polypropylene and the like are known. However, although the polyvinyl chloride label has excellent shrink properties, it has a problem of environmental pollution such as generation of chlorine gas at the time of incineration. For polystyrene and PET labels,
Although the heat shrinkability is good, the difference in specific gravity from the PET bottle is small, so that the floating separation is difficult, which hinders the recycling of the PET bottle. Furthermore, in order to obtain sufficient heat shrinkage, a resin having poor heat resistance is used, and there is a problem that when retort sterilization is performed, a printing ink flow is caused by a molten resin. Polypropylene has a large difference in specific gravity from a PET bottle, is easily separated by floating, and is excellent in heat resistance, but is insufficient in low-temperature shrinkage. For the purpose of improving low-temperature shrinkability, propylene / butene-1
A method of adding a copolymer and a method of adding a petroleum resin or a terpene resin (Japanese Patent Application Laid-Open No. 62-62846) are known, but the effect is still insufficient, and a polypropylene resin serving as a base is used. There is a demand for further improvement in shrinkage performance. In recent years, the packaging form of PET bottles has been diversified, and light shrink label packaging that does not require a large shrinkage rate has come to be seen. There is a demand for a film for a shrink label having shrink properties sufficient for light shrink label packaging and low specific gravity.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polypropylene resin composition having improved heat shrinkage, especially low temperature shrinkage under such circumstances, and a heat shrinkable shrink label film using the same. To provide.

[0004]

Means for Solving the Problems The present inventors have conducted various studies to solve the above problems, and as a result, have found that a specific crystalline propylene / α-olefin random copolymer has a specific alicyclic carbonization property. The present inventors have found that a heat-shrinkable polypropylene shrink label film having improved low-temperature shrinkage can be obtained by using a resin composition containing a small amount of a hydrogen resin, thereby completing the present invention.

That is, according to the present invention, the following characteristics:
Crystalline propylene / α-olefin random copolymer containing propylene as a main component that satisfies the characteristics above 95 to 10
A resin composition for a heat-shrinkable polypropylene shrink label comprising less than 0% by weight and less than 5% by weight of an alicyclic hydrocarbon resin having a softening point of 110 ° C. or higher. Characteristics: melt flow rate (230 ° C, 2.16 kg
Load) is 0.5 to 10 g / 10 min. Characteristics: Main melting peak temperature (T _p ) determined by a differential scanning calorimeter (DSC) is in the range of 100 to 140 ° C. Characteristics: T ₅₀ ≦ 125 ° C. (where T ₅₀ is the temperature at which the total heat of fusion of the polypropylene resin composition determined by DSC is ΔHm and the heat of fusion calculated from the low temperature side is 50% of ΔHm) (° C).)

Further, according to the present invention, there is provided a heat-shrinkable polypropylene shrink label film obtained by stretching the above-described heat-shrinkable polypropylene shrink label resin composition at least twice in at least one axial direction. Provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The resin composition for heat-shrinkable polypropylene shrink labels and the film for shrink labels using the same according to the present invention will be described in detail below.

[I] Resin composition for label Crystalline propylene / α-olefin random copolymer (1) Characteristics: Melt flow rate (hereinafter abbreviated as MFR) MFR of crystalline propylene / α-olefin random copolymer used in the present invention (230 ° C, 2. 16kg load)
Is 0.5 to 10 g / 10 min, preferably 1.0 to 10 g
g / 10 minutes. If the MFR is less than 0.5 g / 10 minutes, the extrusion characteristics may be deteriorated and the productivity may be reduced. On the other hand, if the MFR is more than 10 g / 10 minutes, the shrinkage characteristics may be deteriorated or the thickness may be uneven.

[0009] (2) Characteristics: DSC in the determined principal melting peak temperature (T _p) crystalline propylene · alpha-olefin random copolymer of the DSC in the obtained primary melting peak temperature used in the present invention (T _p) is 100-140 ° C, preferably 100-1
The temperature is 30 ° C, more preferably 100 to 125 ° C. If the melting peak temperature (T _p ) is less than 100 ° C., the unstretched sheet is difficult to solidify by cooling, and film formation becomes difficult. On the other hand, if it exceeds 140 ° C., the shrinkage properties become insufficient.

(3) Characteristics: Relation between heat of fusion and temperature The crystalline propylene / α-olefin random copolymer used in the present invention needs to satisfy the following formula. T ₅₀ ≦ 125 ° C. (where T ₅₀ is the temperature (° C.) when the total heat of fusion of the polypropylene resin composition determined by DSC is ΔHm and the heat of fusion calculated from the low temperature side is 50% of ΔHm. ) is a.) T ₅₀ is, 125 ° C. or less, preferably 120 ° C. or less, more preferably 115 ° C. or less. If T ₅₀ exceeds 125 ° C., the shrinkage properties deteriorate.

(4) Constituent components of the crystalline propylene / α-olefin random copolymer The α-olefin which is randomly copolymerized with propylene of the crystalline propylene / α-olefin random copolymer used in the present invention.
Examples of the olefin include ethylene or an α-olefin having 4 to 20 carbon atoms, and it is preferable to use ethylene, butene-1, hexene-1, octene-1, and the like,
The crystalline propylene α of the present invention is particularly preferably ethylene.
-Olefin random copolymer is not limited as long as it satisfies the above-mentioned properties-properties, usually α- olefin content in the random copolymer is 2.0 to 30
%, Especially when the α-olefin is ethylene, 2.0 to 10% by weight, preferably 2.0 to 6.0%.
% By weight. Moreover, as long as it is a crystalline propylene-α-olefin random copolymer satisfying the above characteristics to characteristics, two or more kinds may be used in combination.

<Production of random copolymer>
The method for producing a crystalline propylene / α-olefin random copolymer satisfying the above condition is not limited, but it is preferable to carry out polymerization using a metallocene catalyst. Examples of the metallocene catalyst include the following (i) to (iii) systems, with (i) being particularly preferred. (I) Component (A): metallocene-based transition metal compound Component (B): ion-exchangeable layered silicate and, if necessary, component (C): a system comprising an organoaluminum compound (ii) Component (A): Metallocene transition metal compound A system comprising component (D) and, if necessary, component (C) (iii) A system comprising component (A), component (E), and, if necessary, component (C) Each component constituting the metallocene catalyst will be described.

<Metalocene catalyst (i)> The component (A) comprises:
A metallocene transition metal compound represented by the following general formula (1)
Or (2). _{Q (C 5 H 4-a} R 1 a) (C 5 H 4-b R 2 b) MeXY (1) (C 5 H 4-a R 1 a) (C 5 H 4-b R 2 b) MeXY (2) _{[wherein, C 5 H 4-a R} 1 a and ^{_{C 5 H 4-b R 2}} b each represent a conjugated five-membered ring ligands, Q is two conjugated five-membered ring ligand A divalent hydrocarbon group having 1 to 20 carbon atoms, a silylene group having a hydrocarbon group having 1 to 20 carbon atoms, or a germylene group having a hydrocarbon group having 1 to 20 carbon atoms And Me represents zirconium or hafnium; X and Y each independently represent hydrogen, a halogen group, a hydrocarbon group having 1 to 20 carbon atoms,
0 alkoxy group, C1-20 alkylamide group, trifluoromethanesulfonic acid group, C1-20
A phosphorus-containing hydrocarbon group or a silicon-containing hydrocarbon group having 1 to 20 carbon atoms.

R ¹ and R ² are substituents on the conjugated five-membered ring ligand, and each independently represents a hydrocarbon group having 1 to 20 carbon atoms, a halogen group, an alkoxy group, or a silicon-containing hydrocarbon. Group, a phosphorus-containing hydrocarbon group, a nitrogen-containing hydrocarbon group or a boron-containing hydrocarbon group. Two adjacent R ¹ or two R ² may be bonded to each other to form a ring. a and b are integers satisfying 0 ≦ a ≦ 4 and 0 ≦ b ≦ 4. With the proviso that the two 5-membered ring ligands having R ¹ and R ² are, in terms of relative position via the group Q,
It is asymmetric with respect to the plane containing Me. ]

[0015] Q is as described above, a bonding group for cross-linking two conjugated five-membered ring ligand ^{_{C 5 H 4-a R 1}} a and ^{_{C 5 H 4-b R 2}} b, specifically Specifically, for example, (A) carbon number 1-2
0, preferably 1 to 6 divalent hydrocarbon groups, specifically, for example, an alkylene group, a cycloalkylene group, an arylene and the like, a (II) hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Having a silylene group, (c) having 1 to 2 carbon atoms
There are 0, preferably 1 to 12, germylene groups having hydrocarbon groups.

Regardless of the number of carbon atoms, the distance between the two bonds of the divalent Q group is about 4 atoms or less, especially 3 atoms or less when Q is chain-like. In the case of having a cyclic group, it is preferred that the cyclic group is not more than about +2 atoms, particularly, the cyclic group alone. Therefore, in the case of an alkylene group, ethylene and isopropylidene (the distance between bonds is 2 atoms and 1 atom), in the case of a cycloalkylene group, cyclohexylene (the distance between bonds is only a cyclohexylene group) and in the alkylsilylene group, In this case, dimethylsilylene (the distance between bonds is 1 atom) is preferable. Me is titanium, zirconium or hafnium, preferably zirconium or hafnium.

X and Y may be each independently, that is, they may be the same or different; (a) hydrogen, (b) halogen (fluorine, chlorine, bromine or iodine, preferably chlorine), (c) carbon number 1 A hydrocarbon group having 1 to 20 carbon atoms, (d) an alkoxy group having 1 to 20 carbon atoms, (e) an alkylamide group having 1 to 20 carbon atoms, (f) a phosphorus-containing hydrocarbon group having 1 to 20 carbon atoms, (g) It represents a silicon-containing hydrocarbon group having 1 to 20 carbon atoms or a (thi) trifluoromethanesulfonic acid group.

R ¹ and R ² are substituents on the conjugated five-membered ring ligand, each independently being a hydrocarbon group having 1 to 20 carbon atoms, a halogen group, an alkoxy group having 1 to 20 carbon atoms. Group, silicon-containing hydrocarbon group having 3 to 20 carbon atoms, 2 carbon atoms
A phosphorus-containing hydrocarbon group, a nitrogen-containing hydrocarbon group having 2 to 20 carbon atoms, or a boron-containing hydrocarbon group having 2 to 20 carbon atoms. Further, two adjacent R ¹ or two R ² may be bonded at the ω-terminal to form a ring together with a part of the cyclopentadienyl group. As a typical example of such a case, two adjacent R ¹ (or R ² ) on the cyclopentadienyl group share a double bond of the cyclopentadienyl group to form a fused six-membered ring. (Ie, an indenyl group and a fluorenyl group) and those forming a fused seven-membered ring (ie, an azulenyl group). a and b are 0 ≦ a ≦ 4, 0 ≦ b
It is an integer satisfying ≦ 4.

Non-limiting examples of the metallocene compound represented by the above general formula (1) include the following. In addition, these compounds are indicated by only chemical names, but needless to say, the three-dimensional structure has the asymmetry referred to in the present invention. Although only the case where zirconium is used as Me is exemplified, hafnium may be directly substituted instead.

A transition metal compound having two silylene-bridged five-membered ring ligands, for example, (1) dimethylsilylenebis (1
-Indenyl) zirconium dichloride, (2) dimethylsilylenebis {1- (2-methyl-4-phenyl-4)
H-azulenyl) {zirconium dichloride, (3) dimethylsilylenebis [1- {2-methyl-4- (1-naphthyl) indenyl}] zirconium dichloride,
(4) methylphenylsilylenebis {1- (2,4-dimethylindenyl)} zirconium dichloride, (5)
Methylphenylsilylenebis [1- {2-methyl-4-
(1-naphthyl) indenyl}] zirconium dichloride,

(6) Dimethylsilylenebis {1- (2-)
Methyl-4-phenylindenyl) zirconium dimethyl, (7) dimethylsilylene bis {1- (2-ethyl-4-phenyl-4H-azulenyl)} zirconium dichloride, (8) dimethylsilylene} 1- (2-ethyl -4-phenyl-4,5,6,7,8-pentahydroazulenyl) {1- (2,3,5-trimethylcyclopentadienyl)} zirconium dichloride, (9) dimethylsilylenebis {1- (2-ethyl-4- (pentafluorophenyl) indenyl)} zirconium dichloride and the like.

The five-membered ring ligand bridged with an alkylene group is
Transition metal compounds having, for example, (1) ethylene-
1,2-bis (1-indenyl) zirconium dichloride, (2) ethylene-1,2-bis {1- (2,4-dimethylindenyl)} zirconium dichloride, (3)
Ethylene-1,2-bis {1- (2-methyl-4-phenylindenyl)} zirconium dichloride, (4) ethylene-1,2-bis {1- (2-methyl-4,5-benzoindenyl) )} Zirconium dichloride, (5) ethylene-1,2-bis [1- {2-methyl-4- (4-
Chlorophenyl) -4H-azulenyl}] zirconium dichloride.

A transition metal compound having a five-membered ring ligand bridged by a hydrocarbon residue containing germanium, aluminum, boron, phosphorus or nitrogen, such as (1) dimethylgermylene bis (1-indenyl) zirconium dichloride; (2) dimethylgermylenebis {1- (2-methyl-4-phenyl-4H-azulenyl)} zirconium dichloride, (3) dimethylgermylenebis {1- (2)
-Methyl-4,5-benzoindenyl) zirconium dichloride, (4) phenylphosphinobis (1-indenyl) zirconium dichloride, (5) phenylaminobis (1-indenyl) zirconium dichloride and the like. Among these complexes, particularly preferred are complexes having an azulene skeleton.

As the metallocene transition metal compound represented by the general formula (2), the following compounds can be exemplified. (1) bis (1-indenyl) zirconium dichloride, (2) bis {1- (2-methyl-4-phenyl-4)
H-azulenyl) {zirconium dichloride, (3) bis [1- {2-methyl-4- (1-naphthyl) indenyl}] zirconium dichloride, (4) bis {1-
(2,4-dimethylindenyl)} zirconium dichloride, (5) bis [1,1 ′-{2-methyl-4- (4
-Chlorophenyl) -4H-azulenyl}] zirconium dichloride

(6) Bis [1,1 '-{2-methyl-4
-(4-chloro-2-naphthyl) -4H-azulenyl}] zirconium dichloride (7) bis {1,1 '-(2-ethyl-4-phenyl-
4H-azulenyl) zirconium dichloride (8) bis {1,1 '-(2-methyl-4-phenylhexahydroazulenyl)} zirconium dichloride (9) bis [1,1'-{2-methyl-4- (4-chlorophenyl) hexahydroazulenyl}] zirconium dichloride (10) bis [1,1 ′-{2-methyl-4- (4-chloro-2-naphthyl) hexahydroazulenyl}] zirconium dichloride (11) Bis (1-fluorenyl) zirconium dichloride, (12) bis {1- (2-methyl-4-phenyl-4H-fluorenyl)} zirconium dichloride. Here, only the case of zirconium as Me has been exemplified, but instead, hafnium can be directly substituted and named.

The component (B) is an ion-exchange layered silicate. The ion-exchangeable phyllosilicate is a silicate compound having a crystal structure in which planes formed by ionic bonds and the like are stacked in parallel with a weak bonding force, and refers to a contained ion-exchangeable silicate. Most ion-exchanged phyllosilicates occur naturally mainly as a main component of clay minerals, but these ion-exchanged phyllosilicates are not limited to those of natural origin but are artificially synthesized. You may. Specific examples include kaolins such as dickite, nacrite, kaolinite, anorthite, metahalloysite, halloysite, serpentine groups such as chrysotile, risaludite, antigorite, montmorillonite, zaukonite, beidellite, nontronite, saponite, Smectites such as hectorite and stevensite, vermiculites such as vermiculite, mica, illite, sericite, mica such as sea green stone, attapulgite, sepiolite, palygorskite, bentonite, pyrophyllite, talc, and chlorite. Can be These may form a mixed layer.

Among these, montmorillonite, zaukonite, beidellite, nontronite, saponite,
Smectites such as hectorite, stevensite, bentonite and teniolite, vermiculites and mica are preferred. When a compound having a radius of 20 angstroms or more and a pore volume of less than 0.1 cc / g measured by a mercury intrusion method is used as component B, a high polymerization activity tends to be difficult to obtain. / G or more,
In particular, those having 0.3 to 5 cc / g are preferable. Component B can be used as it is without any particular treatment, but it is also preferable to subject component B to a chemical treatment. Here, the chemical treatment may be any of a surface treatment for removing impurities adhering to the surface and a treatment that affects the structure of the clay.

Specific examples include acid treatment, alkali treatment, salt treatment, and organic substance treatment. The acid treatment increases the surface area by removing impurities on the surface and eluting cations such as Al, Fe, and Mg in the crystal structure.
Alkali treatment destroys the crystal structure of the clay, resulting in a change in the structure of the clay. In salt treatment and organic matter treatment,
An ion complex, a molecular complex, an organic derivative, or the like can be formed to change a surface area or an interlayer distance. By replacing the exchangeable ions between the layers with another large bulky ion by utilizing the ion exchange property, a layered material in which the layers are expanded can be obtained. That is, the bulky ions play a pillar-like role of supporting the layered structure, and are called pillars. Introducing another substance between layered substance layers is called intercalation.

Examples of the guest compound to be intercalated include cationic inorganic compounds such as TiCl ₄ and ZrCl ₄ , Ti (OR) ₄ , Zr (OR) ₄ , PO (OR) ₃ ,
Metal alcoholates such as B (OR) ₃ [R is alkyl, aryl, etc.], [Al ₁₃ O ₄ (OH) ₂₄ ] ₇₊ , [Zr ₄ (O
H) ₁₄ ] ₂₊ , and metal hydroxide ions such as [Fe ₃ O (OCOCH ₃ ) ₆ ] ₊ . These compounds may be used alone or in combination of two or more.
When intercalating these compounds, Si
A polymer obtained by hydrolyzing a metal alcoholate such as (OR) ₄ , Al (OR) ₃ , Ge (OR) _{4, and} a colloidal inorganic compound such as SiO ₂ can also be present. Examples of pillars include oxides formed by intercalating the hydroxide ions between layers and then heating and dehydrating. Component B may be used as it is, or may be used after heat dehydration treatment. Further, they may be used alone or as a mixture of two or more of the above solids.

As the ion-exchange layered silicate, at least 40%, preferably 6%, of the exchangeable Group 1 metal cation contained in the ion-exchange layered silicate before being treated with salts.
0% or more of a cation dissociated from the following salts,
Preferably, ion exchange is performed. The salt used in the salt treatment for the purpose of ion exchange is a compound containing a cation containing at least one atom selected from the group consisting of Group 2 to 14 atoms,
A compound comprising a cation containing at least one atom selected from the group consisting of Group 14 atoms and at least one anion selected from the group consisting of halogen atoms, inorganic acids and organic acids, more preferably , A cation containing at least one atom selected from the group consisting of Group 2-14 atoms, Cl, Br, I, F, PO ₄ , SO ₄ , NO
₃ , CO ₃ , C ₂ O ₄ , OCOCH ₃ , CH ₃ COCHCOC
H ₃ , OCl ₃ , O (NO ₃ ) ₂ , O (ClO ₄ ) ₂ , O (S
O ₄ ), OH, O ₂ Cl ₂ , OCl ₃ , OCOH, OCOC
It is a compound comprising at least one anion selected from the group consisting of H ₂ CH ₃ , C ₂ H ₄ O ₄ and C ₆ H ₅ O ₇ .

Specifically, CaCl_Two, CaSO_Four, Ca
C_TwoO_Four, Ca (NO_Three)_Two, Ca_Three(C₆H_FiveO₇)_Two, Mg
Cl_Two, Sc (OCOCH_Three)_Two, ScF_Three, ScBr_Three,
Y (OCOCH_Three)_Three, LaPO_Four, La_Two(SO_Four)_Three, S
m (OCOCH_Three)_Three, SmCl_Three, Yb (NO_Three)_Three, Y
b (ClO_Four)_Three, Ti (OCOCH_Three)_Four, Ti (C
O_Three)_Two, Ti (SO_Four)_Two, TiF_Four, TiCl_Four, Zr
(OCOCH_Three)_Four, Zr (CO_Three)_Two, Zr (NO_Three)_Four,
ZrOCl_Two, Hf (SO_Four)_Two, HfBr_Four, HfI_Four,
V (CH_ThreeCOCHCOCH_Three)_Three, VOSO_Four, VC
l_Four, VBr_Three, Nb (CH _ThreeCOCHCOCH_Three)_Five, N
b_Two(CO_Three)_Five, Ta_Two(CO_Three)_Five, Ta (NO)_Five, T
aCl_Five, Cr (OOCH_Three)_TwoOH, Cr (NO_Three)_Three,
Cr (ClO_Four)_Three, MoOCl_Four, MoCl_Three, MoCl
_Four, MoCl_Five, MoF₆, WCl_Four, WBr_Five, Mn (C
H_ThreeCOCHCOCH_Three)_Two, Mn (NO_Three)_Two, Fe (O
COCH_Three)_Two, Fe (NO_Three)_Three, FeSO_Four, Co (O
COCH_Three)_Two, Co_Three(PO_Four)_Two, CoBr_Two, NiCO
_Three, NiC_TwoO_Four, Pb (OCOCH_Three)_Four, Pb (OOC
H_Three)_Two, PbCO_Three, Pb (NO_Three)_Two, CuI_Two, CuB
r_Two, CuC_TwoO_Four, Zn (OOCH_Three)_Two, Zn (CH_ThreeC
OCHCOCH_Three)_Two, Cd (OCOCH_TwoCH_Three)_Two, C
dF_Two,, AlCl_Three, Al_Two(C_TwoO_Four)_Three, Al (CH_Three
COCHCOCH_Three)_Three, GeCl_Four, GeBr_Four, Sn
(OCOCH_Three)_Four, Sn (SO_Four)_TwoAnd the like.

In addition to removing impurities on the surface, the acid treatment can elute a part or all of cations such as Al, Fe and Mg having a crystal structure. The acid used in the acid treatment is preferably selected from hydrochloric acid, sulfuric acid, nitric acid, oxalic acid, phosphoric acid and acetic acid. The salt and the acid used for the treatment may be two or more. When combining the salt treatment and the acid treatment, after performing the salt treatment, a method of performing an acid treatment,
There is a method of performing a salt treatment after performing the acid treatment, and a method of simultaneously performing the salt treatment and the acid treatment.

The conditions for treatment with salts and acids are not particularly limited, but usually the concentration of salts and acids is 0.1 to 3
0% by weight, treatment temperature is from room temperature to boiling point, treatment time is from 5 minutes to
It is preferable to select the condition for 24 hours and to elute at least a part of at least one compound contained in the ion-exchange layered silicate. Further, salts and acids are generally used in an aqueous solution.

In the salt treatment and / or the acid treatment, the shape may be controlled by pulverization or granulation before, during, or after the treatment. Further, a chemical treatment such as an alkali treatment or an organic substance treatment may be used in combination. These ion-exchange layered silicates usually contain adsorbed water and interlayer water. In the present invention, it is preferable to remove these adsorbed water and interlayer water to use as component B.

Here, the adsorbed water is water adsorbed on the surface of the compound particles of the ion-exchangeable layered silicate or on the crystal fracture surface, and the interlayer water is water existing between the layers of the crystal. In the present invention, these adsorbed water and / or interlayer water can be removed by heat treatment before use. The method of heat treatment of the adsorbed water and interlayer water of the ion-exchanged layered silicate is not particularly limited, and methods such as heat dehydration, heat dehydration under gas flow, heat dehydration under reduced pressure, and azeotropic dehydration with an organic solvent are used. Can be The temperature at the time of heating cannot be specified unconditionally because it depends on the types of ion-exchanged layered silicate and interlayer ions. However, the temperature is 100 ° C. or higher, preferably 150 ° C. or higher, so that interlayer water does not remain. Is not preferable (for example, 800 ° C. or higher, depending on the heating time). Further, a heat dehydration method for forming a crosslinked structure such as heating under air flow is not preferable because the polymerization activity of the catalyst is reduced. The heating time is at least 0.5 hour, preferably at least 1 hour. At this time, component B after removal
Is preferably 3% by weight or less, more preferably 1% by weight or less, assuming that the moisture content when dehydrated for 2 hours at a temperature of 200 ° C. and a pressure of 1 mmHg is 0% by weight.

As the component B, it is preferable to use spherical particles having an average particle size of 5 μm or more. More preferably, spherical particles having an average particle size of 10 μm or more are used. More preferably, spherical particles having an average particle diameter of 10 μm or more and 100 μm or less are used. The average particle size here is represented by a number average particle size calculated by performing image processing on an optical microscope photograph (100 times magnification) of the particles. Component B may be a natural product or a commercially available product as long as the shape of the particles is spherical.
Particles in which the shape and particle size of the particles are controlled by a particle diameter, a separation, or the like may be used.

The granulation methods used here include, for example, stirring granulation, spray granulation, tumbling granulation, briquetting, compacting, extrusion granulation, fluidized bed granulation, and emulsion granulation. , A submerged granulation method, a compression molding granulation method and the like, but are not particularly limited as long as the component B can be granulated. The granulation method is preferably a stirring granulation method, a spray granulation method, a tumbling granulation method, or a fluidized bed granulation method, and particularly preferably a stirring granulation method or a spray granulation method. When spray granulation is performed, water or an organic solvent such as methanol, ethanol, chloroform, methylene chloride, pentane, hexane, heptane, toluene, or xylene is used as a dispersion medium for the raw material slurry. Preferably, water is used as the dispersion medium. The concentration of the component B in the raw slurry liquid for spray granulation to obtain spherical particles is 0.1 to 70%, preferably 1 to 50%.
%, Particularly preferably 5 to 30%. The temperature of the inlet of the hot air for spray granulation from which spherical particles can be obtained varies depending on the dispersion medium, but when water is used as an example, the temperature is 80 to 260 ° C., preferably 1 to 260 ° C.
Perform at 00-220 ° C.

In the granulation, an organic substance, an inorganic solvent, an inorganic salt, and various binders may be used. Examples of the binder used include sugar, dextrose, corn syrup, gelatin, glue, carboxymethyl celluloses, polyvinyl alcohol, water glass, magnesium chloride, aluminum sulfate, aluminum chloride, magnesium sulfate, alcohols, glycol, starch, casein,
Latex, polyethylene glycol, polyethylene oxide, tar, pitch, alumina sol, silica gel,
Gum arabic, sodium alginate and the like can be mentioned.

The spherical particles obtained as described above preferably have a compressive breaking strength of 0.2 MPa or more in order to suppress crushing and fine powder in the polymerization step. In the case of such a particle strength, the effect of improving the particle properties is effectively exhibited, particularly when prepolymerization is performed.

As the organoaluminum compound (component C) used as an optional component in addition to the components A and B, a compound represented by the following general formula (3) is suitable. The ^{_{(AlR 3 n X 3-n}} ) m (3) in the present invention compound represented by the formula alone, can be used in or in combination as a mixture of two or more. Also,
This use is possible not only at the time of catalyst preparation but also at the time of prepolymerization or polymerization. In this formula, R ³ has 1 to 20 carbon atoms.
X represents a halogen, hydrogen, an alkoxy group, or an amino group. n is an integer of 1-3 and m is an integer of 1-2. R ³ is preferably an alkyl group.
Is preferably chlorine when it is halogen, alkoxy group having 1 to 8 carbon atoms when it is an alkoxy group, and amino group having 1 to 8 carbon atoms when it is an amino group. Therefore, specific examples of preferred compounds include trimethylaluminum, triethylaluminum, trinormal propyl aluminum, trinormal butyl aluminum,
Triisobutyl aluminum, tri normal hexyl aluminum, tri normal octyl aluminum, tri normal decyl aluminum, diethyl aluminum chloride, diethyl aluminum sesquichloride, diethyl aluminum hydride, diethyl aluminum ethoxide, diethyl aluminum dimethyl amide, diisobutyl aluminum hydride, diisobutyl aluminum chloride, etc. Is mentioned. Of these, preferred are m = 1, n = 3 trialkylaluminum and dialkylaluminum hydride. More preferably, R ³ is a trialkyl aluminum having 1 to 8 carbon atoms.

<Metallocene Catalyst (ii)> Another example of the metallocene catalyst used in the present invention is a catalyst in which the metallocene transition metal compound (component A) is combined with an aluminum oxy compound (component D). Also in this case, as an optional component, an organoaluminum compound (component C)
Can be used in combination. Specific examples of the aluminum oxy compound (component D) include the following general formula (4):
Compounds represented by (5) and (6) are mentioned.

[0042]

Embedded image

In the above formulas, R ⁴ represents a hydrogen atom or a hydrocarbon residue, preferably a hydrocarbon residue having 1 to 10 carbon atoms, more preferably a hydrocarbon residue having 1 to 6 carbon atoms. In addition, a plurality of R ⁴
May be the same or different. Also, p is 0
And an integer of 2 to 30, preferably 2 to 30.

The compounds represented by the general formulas (4) and (5) are compounds also called alumoxanes, and are obtained by reacting one kind of trialkylaluminum or two or more kinds of trialkylaluminums with water. Specifically, (a) methylalumoxane, ethylalumoxane, propylalumoxane, butylalumoxane, isobutylalumoxane obtained from one type of trialkylaluminum and water, (b) two types of trialkylaluminum and Examples thereof include methylethylalumoxane, methylbutylalumoxane, and methylisobutylalumoxane obtained from water. Of these, methylalumoxane or methylisobutylalumoxane is preferred.

The compound represented by the general formula (6) is a compound of 10: 1 to 1 type of trialkylaluminum or two or more trialkylaluminums and an alkylboronic acid represented by the following general formula (7). It can be obtained by a 1: 1 (molar ratio) reaction. In the general formula (7), R ⁵ represents a hydrocarbon residue having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms or a halogenated hydrocarbon group. R ⁵ B (OH) ₂ (7) Specifically, the following reaction products can be exemplified. (A) Trimethylaluminum and methylboronic acid 2:
(B) 2: 1 reaction product of triisobutylaluminum and methylboronic acid (c) 1: 1: 1 reaction product of trimethylaluminum, triisobutylaluminum and methylboronic acid (d) 2: 2 reaction of trimethylaluminum and methylboronic acid
1 Reactant (e) Triethylaluminum and butylboronic acid 2:
1 reactant

<Metallocene Catalyst (iii)> As another example of the metallocene catalyst used in the present invention, the metallocene-based transition metal compound (component A) is reacted with component A to form stable ions. And a catalyst combined with a specific compound (component E). Also in this case, an organic aluminum compound (component C) can be used in combination as an optional component.

The specific compound (E) is an ionic compound or an electrophilic compound formed from an ion pair of a cation and an anion, and reacts with a metallocene compound to form a stable ion to form a polymerization active species. To form. Among them, the ionic compound is represented by the general formula (8). [Q '] ^{m +} [Y] ^m- (M is an integer of 1 or more) (8) In the formula, Q ′ is a cation component of an ionic compound, and examples thereof include a carbonium cation, a tropylium cation, an ammonium cation, an oxonium cation, a sulfonium cation, and a phosphonium cation.
Metal cations and organic metal cations which are themselves easily reduced can also be mentioned. These cations
Not only a cation capable of giving a proton as disclosed in Japanese Patent Publication No.
A cation that does not give a proton may be used. Specific examples of these cations include triphenylcarbonium, diphenylcarbonium, cycloheptatrienium, indenium, triethylammonium, tripropylammonium, tributylammonium, NNdimethylammonium, dipropylammonium, dicyclohexylammonium, triphenylphosphonium, Trimethylphosphonium, tri (dimethylphenyl) phosphonium, tri (methylphenyl) phosphonium, triphenylsulfonium, triphenyloxonium, triethyloxonium, pyrylium, silver ion, gold ion, platinum ion, palladium ion, mercury ion, ferro A cerium ion and the like.

Y is an anionic component of an ionic compound, which is a component which reacts with a metallocene compound to form a stable anion, such as an organic boron compound anion, an organic aluminum compound anion, an organic gallium compound anion, and an organic phosphorus compound. Anions, organic arsenic compound anions, organic antimony compound anions and the like can be mentioned. Specifically, tetraphenylboron, tetrakis (3,
4,5-trifluorophenyl) boron, tetrakis (3,5-di (trifluoromethyl) phenyl) boron, tetrakis (3,5- (t-butyl) phenyl) boron, tetrakis (pentafluorophenyl) boron,
Tetraphenylaluminum, tetrakis (3,4,5
-Trifluorophenyl) aluminum, tetrakis (3,5-di (trifluoromethyl) phenyl) aluminum, tetrakis (3,5-di (t-butyl) phenyl) aluminum, tetrakis (pentafluorophenyl) aluminum, tetraphenylgallium , Tetrakis (3,4,5-trifluorophenyl) gallium, tetrakis (3,5-di (trifluoromethyl) phenyl) gallium, tetrakis (3,5-di (t-butyl)
Phenyl) gallium, tetrakis (pentafluorophenyl) gallium, tetraphenylphosphorus, tetrakis (pentafluorophenyl) phosphorus, tetraphenylarsenic, tetrakis (pentafluorophenyl) arsenic, tetraphenylantimony, tetrakis (pentafluorophenyl) antimony, decaborate, Undecaborate, carbado decaborate, decachloro decaborate and the like can be mentioned.

As the electrophilic compound, among the compounds known as Lewis acid compounds, those which react with metallocene compounds to form stable ions to form polymerization active species, and include various metal halides Examples include compounds and metal oxides known as solid acids. Specific examples include magnesium halides and Lewis acidic inorganic compounds. These catalyst components can be used by being appropriately supported on an inorganic solid carrier, an organic solid carrier, or the like.
Examples of the loading include the methods described in JP-A-61-296008, JP-A-1-101315, JP-A-5-301917, and the like.

<Formation of catalyst> Component A, component B, and
It can be prepared by contacting the metallocene catalyst comprising component C, which is used if necessary, in a polymerization tank or outside the polymerization tank in the presence or absence of the monomer to be polymerized. Component A and component D or component E
The catalyst can be prepared in the same manner also in the case of combining. Further, the catalyst may be one obtained by performing prepolymerization in the presence of an olefin. As the olefin used for the prepolymerization, propylene, ethylene, 1-butene, 3-olefin
Methylbutene-1, styrene, divinylbenzene and the like are used.

<Polymerization> In the polymerization of the crystalline propylene-α-olefin random copolymer used in the present invention, the catalyst prepared as above is mixed with propylene and ethylene or an α-olefin having 4 to 20 carbon atoms. It is performed by mixing and contacting. The amount ratio of each monomer in the reaction system does not need to be constant over time, and it is convenient to supply each monomer at a constant mixing ratio, and to change the mixing ratio of the supplied monomers over time. Is also possible. Further, any of the monomers can be dividedly added in consideration of the copolymerization reaction ratio.

As the polymerization mode, any method can be adopted as long as the catalyst component and each monomer are efficiently contacted. Specifically, a slurry method using an inert solvent, a bulk method using propylene as a solvent without substantially using an inert solvent, a solution method, or substantially converting each monomer into a substantially gaseous state without using a substantially liquid solvent A keeping gas phase method can be employed. Either continuous polymerization or batch polymerization may be used. In the case of slurry polymerization, a single or a mixture of saturated aliphatic or aromatic hydrocarbons such as hexane, heptane, pentane, cyclohexane, benzene, and toluene can be used as a polymerization solvent.

As the polymerization conditions, the polymerization temperature is -78 to 16
The temperature is 0 ° C., preferably 0 to 150 ° C., and hydrogen may be used as a molecular weight regulator at that time. The polymerization pressure is from 0 to 90 kg / cm ² · G, preferably from 0 to 60 kg / cm ² · G, particularly preferably from 1 to 50 k / cm ² · G.
g / cm ² · G.

2. Alicyclic hydrocarbon resin Examples of the alicyclic hydrocarbon resin used in the present invention include:
Examples include petroleum resins, terpene resins, rosin-based resins, coumarone-indene resins, and hydrogenated derivatives thereof. Among these, those having no polar group or resins having a hydrogenation ratio of 95% or more by adding hydrogen are preferable. More preferred resins are petroleum resins or hydrogenated derivatives of petroleum resins, and examples of the petroleum resins include commercially available products such as Alcon manufactured by Arakawa Chemical Industry Co., Ltd. and Escolets manufactured by Tonex Corporation.

The softening point of the alicyclic hydrocarbon resin is 110
C. or higher, preferably 115 ° C.
The temperature is more preferably 125 ° C. or more. If the softening point of the alicyclic hydrocarbon resin is lower than 110 ° C., the film becomes sticky or becomes cloudy due to a change with time.

3. Compounding ratio of resin composition Crystalline propylene-α- in the resin composition used in the present invention
The blending ratio of the olefin random copolymer and the alicyclic hydrocarbon resin is mainly composed of the crystalline propylene-α-olefin random copolymer, and the content is 95%.
Ultra-less than 100% by weight. On the other hand, the content of the alicyclic hydrocarbon resin is less than 5% by weight. When the content of the alicyclic hydrocarbon resin is 5% by weight or more, the separability from the PET bottle deteriorates, and the label film becomes sticky.

4. Other Components An antioxidant, an antistatic agent, a neutralizing agent, a nucleating agent, an antiblocking agent, a slip agent and the like can be added as long as the effects of the present invention are not impaired. In order not to impair the effects of the present invention, propylene-butene-1 copolymer and polybutene-
1. Known shrinkage property improving components such as linear low density polyethylene may be added.

[II] Method for Forming Shrink Label Film The heat-shrinkable polypropylene shrink label film of the present invention is obtained by subjecting the above polypropylene resin composition to a known forming method such as an inflation method or a flat stretching method. Although it can be molded using, in the present invention,
It is preferable to use a flat stretching method, particularly a tenter type uniaxial stretching method.

After being melt-extruded by the above-mentioned molding method, the film is stretched at least two times or more in at least one axial direction by a known method to produce the shrink label film of the present invention.
The stretching direction may be uniaxial or more, but it is preferable to uniaxially stretch only in a direction perpendicular to the flow direction of the label. On the other hand, if the stretching ratio is less than 2, a sufficient shrinkage cannot be obtained. Further, for the purpose of improving the shrinkage, it is preferable to perform stretching at a temperature as low as possible. In particular, when there is a step of applying preheating to the unstretched sheet, the preheating temperature is set as low as possible within a moldable range. This is preferable from the viewpoint of improving the shrinkage.

The thickness of the shrink label film of the present invention is not particularly limited, but is 100 μm or less, preferably 30 to 80 μm. Further, the film for shrink labels of the present invention can be used as a film for a single-layer label or as a film for a multilayer label having two or more layers. In the case of a multilayer label film, the label film from the resin composition of the present invention may have at least one layer. Examples of the lamination method include a multilayer coextrusion method and a dry lamination method.

[III] Use of Heat Shrinkable Film The heat shrinkable polypropylene shrink label film of the present invention has a greatly improved heat shrinkage,
It has practical characteristics as a material for display labels for bottles, a material for display labels for bottle containers, and the like. Further, since the low-temperature shrinkage ratio is improved, the high-speed label packaging property is excellent, and particularly, it can be suitably used for label packaging in PET bottles and bottle containers preliminarily filled at low temperature.

[IV] Heat Shrinkable Shrink Label The heat shrinkable polypropylene shrink label film of the present invention is formed into a shrink label by processing it into a tubular shape. The processing method is not particularly limited, and a known method can be used. For example, a shrink label can be obtained by applying a center seal to a flat shrink label film so that the main contraction direction of the film is a cylindrical direction. Examples of the center sealing method include sealing by applying an organic solvent, sealing by applying an adhesive, and heat sealing. Printing on the shrink label film is performed at an appropriate time before and after the film is processed into a cylindrical shape.

[0063]

EXAMPLES The present invention will be specifically described with reference to examples below, but the present invention is not limited to these examples. The method for producing the propylene / α-olefin random copolymer, the method for producing the label film, and the method for evaluating the film used in the examples and comparative examples are as follows.

[I] Production method of propylene / α-olefin random copolymer (1) Preparation of solid catalyst component 230 ml of dehydrated / deoxygenated heptane after sufficiently replacing the inside of a 1-liter stirred autoclave with propylene.
Was introduced, and the temperature in the system was maintained at 40 ° C. Here, chemically treated clay slurried with toluene (montmorillonite is treated with sulfuric acid / magnesium sulfate at 100 ° C.
(Spray-dried from a water slurry) 10 g was added.
Further, in a separate container, 0.15 mmol of racemic dimethylsilylenebis [1- {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] zirconium dichloride and 1.5 mmol of triisobutylaluminum mixed under toluene. Was added. Where propylene is 10
Introduced at a rate of g / h for 120 minutes, and then polymerization was continued for 120 minutes. Further, the solvent was removed and dried under nitrogen to obtain a solid catalyst component. This solid catalyst component contained 1.9 g of polypropylene per gram of solid component.

(2) Polymerization After sufficiently replacing the inside of a stirring autoclave having an internal volume of 200 l with propylene, liquefied propylene
5 kg were introduced. To this were added 500 ml (0.12 mol) of a triisobutylaluminum / n-heptane solution, 2.0 kg of ethylene, and 3.5 l of hydrogen (as a standard state volume), and the internal temperature was maintained at 30 ° C. Then, 1.45 g of the solid catalyst component was injected with argon to start polymerization, and the temperature was raised to 70 ° C. over 30 minutes, and the temperature was maintained for 1 hour. Here, 100 ml of ethanol was added to stop the reaction. The residual gas was purged to obtain 13.7 kg of a propylene / ethylene random copolymer (PP). A required amount of a propylene / ethylene random copolymer was obtained in the same manner as a sample. The obtained propylene / ethylene random copolymer had the following physical properties. MFR: 2.58 g / 10 min, ethylene content: 3.
42 _{wt%, T p: 122.7 ℃,} T 50: 113 ℃.

[II] Method for producing label film (1) Method for forming unstretched sheet The resin composition is melt-extruded at 200 ° C. by a T-die method.
It was solidified by cooling with a cooling roll at 0 ° C. to obtain an unstretched sheet having a thickness of 300 μm. (2) Method for forming a stretched film The unstretched sheet is introduced into a tenter furnace, and is preheated at the lowest temperature at which it can be formed for 30 seconds, and in an atmosphere at a temperature equal to the preheating temperature, in the width direction for 30 seconds. The film was stretched 5 times, and subsequently annealed at 87 ° C. for 30 seconds while relaxing 7.5% in the width direction in the tenter furnace. A heat shrinkable label film having a draw ratio of 6 times and a thickness of 50 μm was obtained.

[III] Evaluation method of label film (1) Suitability for light shrink label packaging: The label film was cut out in a length of 22.5 cm in the main shrink direction and 15 cm in a direction perpendicular to the main shrink direction. A cylindrical label was obtained by rounding into a cylindrical shape with a circumferential length of 21.5 cm so that the main shrinkage direction was the circumferential direction, and heat-sealing the overlapping portion. The label was covered so that one end of the obtained label was aligned with the lower end of a commercially available plastic bottle (500 ml, for Kirin Namacha). 500 ml of water (25 ° C.) was put into a plastic bottle with a label attached, and the cap was capped, and then immersed in a water tank adjusted to 90 ° C. for 5 seconds. Immediately after the elapse of 5 seconds, the label was packaged by taking it out of the 90 ° C. water bath and immersing it in a separately prepared 25 ° C. water bath for 1 minute or more. A 15.7 cm portion from the lower end of the PET bottle after label packaging (the upper end position of the label on the commercially available PET bottle. Perimeter: 18.0 cm, shrinkage ratio: 16.3%) Check the tightness of the label, and check the 1
A sample having a 5.7 cm portion completely adhered was evaluated as good, and a sample having insufficient adhesion was evaluated as poor.

(2) Specific gravity: The density of the resin composition was measured by a density gradient tube method according to JIS K-7112. (3) Melt flow rate (MFR): JIS K-6
758 (condition 230 ° C., load 2.16 kg). (4) Differential scanning calorimeter (DSC) Using a DSC manufactured by Seiko, a sample (propylene
-Olefin random copolymer) 5.0 mg
After holding at 00 ° C. for 5 minutes, the mixture was cooled to 40 ° C. at a temperature decreasing rate of 10 ° C./min, and further melted at a temperature increasing rate of 10 ° C./min to obtain a heat of fusion curve. T _p and T ₅₀ were determined from the obtained heat of fusion curve. (5) Softening point temperature was measured in accordance with JIS K-2207.

(6) Heat Shrinkage After aging the stretched film at 40 ° C. for 24 hours,
A square having a size of 0 cm × 10 cm is cut out so that one side thereof is parallel to the flow direction of the film, and this is placed in a water tank heated to a predetermined temperature (80 ° C., 90 ° C. or 100 ° C.).
Soaked for seconds. 25 ° C separately prepared immediately after 10 seconds
After immersion in a water tank for 20 seconds, the lengths of the film in the flow direction and in the orthogonal direction were measured.

Example 1 100 parts by weight of a resin mixture consisting of 99.5 parts by weight of PP powder and 0.5 part by weight of an alicyclic hydrocarbon resin (Escolets 228F, manufactured by Tonex Corporation, softening point temperature: 137 ° C.) On the other hand, 0.05 parts by weight of calcium stearate, 0.1 parts by weight of a phenolic antioxidant (Ciba Geigy, trade name Ir1010), 0.1 parts by weight of a phosphorus antioxidant (Ciba Geigy, trade name Ir168) 0.1
Parts by weight, average particle size 2.5 μ as an anti-blocking agent
After mixing 0.1 part by weight of synthetic silica with a Henschel mixer, the mixture was granulated with a 50 mm single screw extruder to obtain a resin composition. The obtained resin composition was used as a raw material and formed into a label film by the method described above. The minimum preheatable temperature at which the film could be formed was 93 ° C. Table 1 shows the evaluation results of the obtained label films.

Example 2 97 parts by weight of PP powder and an alicyclic hydrocarbon resin (Alcon P. manufactured by Arakawa Chemical Industries, Ltd.)
140, softening point 140 ° C.) 100 parts by weight of a resin mixture consisting of 3 parts by weight, 0.05 parts by weight of calcium stearate, 0.1 part by weight of a phenolic antioxidant (Ciba Geigy, trade name Ir1010), phosphorus 0.1 part by weight of an antioxidant (Ciba Geigy Co., trade name Ir168) and 0.1 part by weight of synthetic silica having an average particle size of 2.5 μm as an antiblocking agent were mixed with a Henschel mixer.
Granulation was performed with a 0 mm single screw extruder to obtain a resin composition. The obtained resin composition was used as a raw material and formed into a label film by the above-described method. The minimum preheatable temperature during film formation was 85 ° C. Table 1 shows the evaluation results of the obtained films.

Comparative Example 1 A propylene / ethylene random copolymer (PP) was prepared using a normal Ziegler catalyst.
Was manufactured. The obtained propylene / ethylene random copolymer had the following physical properties. MFR:
2.30 g / 10 min, ethylene content: 3.60% by weight,
_{T p: 138.3 ℃, T 50} : 130 ℃. A resin composition was obtained in the same manner as in Example 1 except that PP powder was replaced with PP powder. The obtained resin composition was used as a raw material and formed into a label film by the method described above. The minimum preheatable temperature for film formation is 1
00 ° C. Table 1 shows the evaluation results of the obtained films. Although the specific gravity was small, the heat shrinkage was smaller than that of Example 1, and the packaging suitability was poor.

[Comparative Example 2] 85 parts by weight of PP powder and an alicyclic hydrocarbon resin (Alcon P manufactured by Arakawa Chemical Industries, Ltd.)
140, 100 parts by weight of a resin mixture consisting of 15 parts by weight of a softening point, 0.05 parts by weight of calcium stearate, 0.1 parts by weight of a phenolic antioxidant (Ciba Geigy, trade name Ir1010), phosphorus 0.1 parts by weight of an antioxidant (Ciba Geigy Co., trade name Ir168) and 0.1 parts by weight of synthetic silica having an average particle size of 2.5 μm as an antiblocking agent were mixed with a Henschel mixer.
Granulation was performed with a 0 mm single screw extruder to obtain a resin composition. The obtained resin composition was used as a raw material and formed into a label film by the method described above. The minimum preheatable temperature during film formation was 85 ° C. Table 1 shows the evaluation results of the obtained films. Although the heat shrinkage and packaging suitability were good, the specific gravity increased.

[0074]

[Table 1]

[0075]

The resin composition for a heat-shrinkable polypropylene shrink label of the present invention and a film using the same have an extremely low specific gravity as compared with other conventional films.
Since the heat shrinkage is greatly improved and the low temperature shrinkage is also improved, it is suitable for use as a shrink label. In particular, the shrink label of the present invention has a specific gravity of less than 1.0 even after being subjected to secondary processing such as printing, and more preferably 0.92 to 0.92.
Since it can be set to about 0.98, it contributes to weight reduction of various containers and enables floating separation from PET bottles by water.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 3/04 G09F 3/04 C // (C08L 23/14 (C08L 23/14 57:02) 57: 02) B29K 23:00 B29K 23:00 105: 02 105: 02 B29L 7:00 B29L 7:00 F term (reference) 4F071 AA15 AA15X AA20 AA20X AA21 AA21X AA82 AA83 AA87 AA88 AF61 AH04 BA01 BB06 BB07 BB08 BC01 4F210 A01 AG01 RA03 RC02 RG02 RG04 RG43 4J002 BA012 BB141 BB151 GG02

Claims (6)

[Claims] An alicyclic compound having a propylene-based crystalline propylene / α-olefin random copolymer of more than 95 to less than 100% by weight and a softening point temperature of 110 ° C. or more, satisfying the following characteristics. 5% by weight of hydrocarbon resin
A heat shrinkable polypropylene resin composition for shrink labels comprising: Characteristics: melt flow rate (230 ° C, 2.16 kg
Load) is 0.5 to 10 g / 10 min. Characteristics: Main melting peak temperature (T _p ) determined by a differential scanning calorimeter (DSC) is in the range of 100 to 140 ° C. Characteristics: T ₅₀ ≦ 125 ° C. (where T ₅₀ is the temperature at which the total heat of fusion of the polypropylene resin composition determined by DSC is ΔHm and the heat of fusion calculated from the low temperature side is 50% of ΔHm) (° C).) 2. The resin composition for a heat-shrinkable polypropylene shrink label according to claim 1, wherein the crystalline propylene / α-olefin random copolymer is a propylene / ethylene random copolymer. 3. The heat-shrinkable polypropylene shrink label resin composition according to claim 1, wherein the crystalline propylene / α-olefin random copolymer is a copolymer obtained by polymerization with a metallocene catalyst. 4. A resin composition for a heat-shrinkable polypropylene shrink label, wherein the density of the resin composition according to claim 1 is 0.91 g / cm ³ or less. 5. A heat-shrinkable polypropylene shrink label film which is stretched at least twice in at least one axial direction using the resin composition according to claim 1. 6. A polyethylene terephthalate bottle to which a shrink label obtained by processing the heat-shrinkable polypropylene shrink label film according to claim 5 is attached.