JPH0759655B2 - Film for shrink wrapping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention has excellent low-temperature shrinkability, good transparency, gloss and blocking resistance, and a small solvent extraction amount, and is suitable for, for example, food hygiene applications. The present invention relates to a resin composition that can be used for a shrink wrapping film and the like, and a shrink wrapping film.

<Prior Art> At present, polyvinyl chloride, polyethylene, polypropylene, etc. are known as materials for shrink wrapping films, but they have advantages and disadvantages, respectively. Has not been done.

Polyvinyl chloride has excellent transparency and excellent low temperature shrinkability, but low temperature resistance and fusing seal part resistance are poor.
There are also food hygiene problems and disposal problems with plasticizers.

As polyethylene, a biaxially stretched film made of linear low density polyethylene has been released.
The transparency is poor and the low-temperature shrinkage has not reached a satisfactory level.

On the other hand, polypropylene-based materials include propylene-ethylene random copolymers copolymerized with about 3 to 5 wt% of ethylene, and 1 to 3 wt% of ethylene and butene-1.
A film obtained by biaxially stretching a propylene-ethylene-butene-1, ternary random copolymer (JP-A-52-16588) copolymerized with about 3 to 10 wt% of ethylene is known.
The low temperature shrinkability is unsatisfactory. In order to improve this low temperature shrinkability, the propylene-ethylene random copolymer with further increased ethylene content was used.
The transparency of the stretched film is lost, and some of them are not preferable because they are bleed whitened over time or have poor blocking resistance.

Next, among the same propylene-based copolymers, Japanese Patent Laid-Open No. 53-
Japanese Patent Laid-Open No. 113692 and Japanese Patent Laid-Open No. 60-127133 disclose films obtained by subjecting a specific propylene-α-olefin copolymer to a stretching treatment, but have good low-temperature shrinkability and transparency. However, the amount of solvent extracted is large, and the former has poor blocking resistance.

Japanese Patent Publication No. 57-24375 discloses propylene-butene-1.
A film obtained by stretching a composition of a random copolymer and isotactic polypropylene is shown.
However, according to the knowledge of the present inventor, what is shown therein is that the low-temperature stretchability is deteriorated and the low-temperature shrinkage is not obtained due to the large amount of solvent extraction and the incorporation of isotactic polypropylene. Things
It also has poor blocking resistance.

A method of blending a propylene-based copolymer with a petroleum resin (Japanese Patent Laid-Open No. 49-99645 and Japanese Patent Laid-Open No. 62-4735) is also known. Although the low temperature shrinkability is improved, the blocking resistance when exposed to temperature becomes poor, and the film tends to spontaneously shrink over time, which is preferable. In addition, petroleum resin is more expensive than propylene-based copolymers, which increases costs and is not preferable.

<Problems to be Solved by the Invention> In view of the above circumstances, the present inventors have remarkably excellent low-temperature shrinkability, excellent transparency, gloss and blocking resistance, and have a solvent extraction amount of The present invention provides a shrink-wrapping film that is small in number and is suitable for, for example, food hygiene.

<Means for Solving Problems> The present invention provides a resin composition comprising a specific propylene-α-olefin copolymer and a specific propylene random copolymer, which is used to form at least one uniaxial direction after film formation. It was found that a film for shrink wrapping having all of the above-mentioned properties can be obtained by stretching the film, and the present invention has been completed.

That is, the present invention relates to (A) a propylene random copolymer having a comonomer content of 4 to 15 wt%, a Vicat softening point of 122 ° C. or lower, and a cold xylene-soluble portion of 15 wt% or lower, and (B) ) Propylene and α-olefin having 4 or more carbon atoms,
Alternatively, a copolymer of propylene, an α-olefin having 4 or more carbon atoms and ethylene, wherein the α-olefin having 4 or more carbon atoms is 8 to 35 mol%, the ethylene content is 5 mol% or less, cold xylene. It consists of two components (A) and (B) whose soluble portion is 15 to 70 wt%, and (A) 5
TECHNICAL FIELD The present invention relates to a shrink wrapping film obtained by forming a resin composition containing ˜9 wt% and (B) 95 to 10 wt% and then stretching the film in at least uniaxial direction.

Hereinafter, the present invention will be described in detail.

The propylene random copolymer (A) used in the composition of the present invention is a periodic crystalline ethylene-propylene random copolymer, ethylene-butene-1-propylene random terpolymer or the like, but the comonomer content is Is a 4 to 15 wt%, and a so-called slurry polymerized product in which components soluble in an (inert) solvent are removed is preferable.

Propylene random copolymer (A) in the present invention
The Vicat softening point of (hereinafter abbreviated as copolymer (A)) is 12
The temperature is 2 ° C or lower, preferably 120 ° C or lower. If the copolymer (A) having a Vicat softening point exceeding the upper limit is used, the low temperature stretchability becomes poor and the low temperature shrinkability becomes poor. In order to improve the low temperature shrinkability, the amount of the copolymer (B) which is another component becomes very large, and the resistance to booking becomes poor, and the solvent extraction amount becomes large, which is not preferable. The present inventors have discovered that when the Vicat softening point of the copolymer (A) is 122 ° C. or lower, the composition with the specific copolymer specified by the copolymer (B) is surprisingly found. In this case, excellent low-temperature shrinkability is achieved while suppressing the solvent extraction amount to a satisfactory level.

The cold xylene-soluble portion (hereinafter, abbreviated as CXS) of the copolymer (A) in the present invention is 15 wt% or less, preferably 13 wt% or less, and more preferably 10 wt% or less. When CXS exceeds the upper limit, the amount of solvent extracted becomes large, which is not preferable.

The melt index (g / 10 minutes) of the copolymer (A) in the present invention is preferably 0.5 to 50 g / 10 minutes.

Propylene and α-olefin having 4 or more carbon atoms used in the composition of the present invention or propylene and α-olefin having 4 or more carbon atoms
The copolymer (B) of olefin and ethylene (hereinafter, abbreviated as the copolymer (B)) is a solvent polymerization method of polymerizing in a solvent,
Alternatively, it can be produced by a gas phase polymerization method in which the polymerization is carried out in a gas phase. In particular, the gas phase polymerization method in which the polymerization is carried out under the condition that a liquid solvent is not substantially present is a copolymer (B) ( It is also economically superior because it is easy to obtain a suitable cold xylene soluble part), and the polymer drying step or solvent purification step can be omitted or greatly simplified. Since it is obtained in the form of powder, it is preferable because the additives are well dispersed in preparing the composition.

Further, it is preferable not to take measures such as peroxide decomposition before preparing the composition, because the powdery state can be maintained.

When producing by gas phase polymerization, it can be carried out using a Kochi fluidized bed reactor, a fluidized bed reactor with a stirrer, a reactor with a stirrer, or the like. Also, it is essential that the polymerization is carried out under the conditions of temperature and pressure at which the gas does not liquefy in the reactor and the polymer particles do not melt and agglomerate.
Preferred polymerization conditions include a temperature range of 40 to 100 ° C and 1
It is a pressure range of up to 50 kg / cm ² (gauge pressure, hereinafter abbreviated as G), more preferably 50 to 80 ° C. and ^{2 to 20} kg / cm ² G. Further, for the purpose of controlling the melt fluidity of the obtained polymer, it is preferable to add a molecular weight modifier such as hydrogen. Polymerization can be carried out by either batch polymerization, continuous polymerization, or a combination of both methods.
The monomer and the molecular weight modifier consumed in the polymerization can be fed to the reactor continuously or intermittently. or,
For the copolymerization, a random copolymer in which a monomer and a comonomer are simultaneously supplied in a constant composition for polymerization is preferably used, but the composition of the monomer to be polymerized can be changed stepwise and continuously. After the polymerization, the obtained copolymer can be washed with an alcohol or a hydrocarbon solvent for the purpose of removing a catalyst residue or a low molecular weight polymer.

The catalyst system used for producing the copolymer (B) used in the composition of the present invention is a known catalyst for stereoregular polymerization of α-olefin, that is, a so-called Ziegler-Natta catalyst, that is, the periodic table It is composed of a catalyst system containing a group IV-VIII transition metal compound and an organic compound of a group I-III typical metal of the periodic table, and preferably contains a third component such as an electron-donating compound. The metal compound or the catalyst component containing the metal compound is preferably solid.

TiCl ₃ is a transition metal compound, but it is known to have α, β, γ, and δ type crystallinity.
In order to stereoregularly polymerize the above α-olefins,
Α, γ, and δ type TiCl ₃ having layered crystallinity are preferable.

TiCl ₃ is generally obtained as a TiCl ₃ composition by reducing TiCl ₄ with hydrogen, metallic aluminum, metallic titanium, an organic aluminum compound, an organic magnesium compound, or the like. A preferred TiCl ₃ composition is so-called TiCl ₃ · AA, which is obtained by reducing TiCl ₄ with metallic aluminum and further activated by mechanical grinding, etc., and reducing TiCl ₄ with an organoaluminum compound, and further adding a complexing agent and a halogen compound. The activated TiCl ₃ composition is more preferred. Also, Ti (OR) _n X
_4-n (R represents a hydrocarbon group having 1 to 20 carbon atoms. N
Represents a number from 0 to 4. An alkoxy group-containing trivalent titanium halide obtained by reducing) with an organoaluminum compound and then treating with an ether compound and TiCl ₄ can be more preferably used.

A TiCl ₃ composition or an alkoxy group-containing trivalent titanium halide is to be combined with diethylaluminum chloride in the presence of hydrogen in liquefied propylene and polymerized at 65 ° C for 4 hours to produce 6,000 g or more of polypropylene per 1 g. Those capable of satisfying are preferable. Such TiCl ₃ composition is disclosed in JP-A-34478, JP-B-55-27085,
It can be produced by the method disclosed in Japanese Patent Application Nos. 57-26508 and 58-138471. Further, trivalent titanium halide containing an alkoxy group is disclosed in JP-A-59-12.
It can be produced by the method disclosed in Japanese Patent No. 6401 or Japanese Patent Laid-Open No. 60-228504.

When a transition metal compound is used as a catalyst component supported on a suitable carrier, various solid polymers, especially α
Polymers of olefins, various solid organic compounds, especially solid hydrocarbons, various solid inorganic compounds, especially oxides, carbonates, halides, etc. can be used. Preferred carriers are magnesium compounds, ie magnesium halides, oxides, hydroxides, hydroxyhalides and the like. The magnesium compound can be used as a complex with other solid substances mentioned above. Commercially available magnesium compounds may be used as they are, but they may be mechanically pulverized, dissolved in a solvent and then precipitated, or treated with an electron-donating compound or an active hydrogen compound, or an organic compound such as a Grignard reagent. A magnesium compound obtained by decomposing a magnesium compound is preferable. In many cases, the operations for obtaining these preferable magnesium compounds are preferably used in combination, and these operations may be carried out at the time of producing the carrier in advance or at the time of producing the catalyst component. A particularly preferred magnesium compound is a halogen compound of magnesium, and a particularly preferred transition metal compound is the halogen compound of titanium described above. Such titanium, magnesium,
A supported catalyst component containing halogen as a main component is one of the more preferable catalyst components in the present invention.
It can be produced by the method disclosed in JP 30407, JP-A-57-599150, or the like. In the present invention, among these, the carrier-containing catalyst component containing an electron-donating compound and containing titanium, magnesium, or halogen as a main component is
It is one of the more preferable catalyst components.

A composite catalyst containing titanium, magnesium, halogen, or an electron-donating compound as a main component, which is not a carrier-supported type, is also one of the more preferable catalyst components in the present invention. It can be produced by the method disclosed in Japanese Patent Application No. 60-59792.

Preferred as the organic compound of a typical metal of Group I to Group III of the Periodic Table is an organic compound of aluminum, particularly a compound represented by the general formula ReAlX _3-e (where R is a hydrocarbon group having 1 to 20 carbon atoms, X
Represents hydrogen or halogen, and e is a number from 1 to 3. ) Is preferred. Specific examples of such compounds include triethyl aluminum, triisobutyl aluminum, diethyl aluminum hydride, diethyl aluminum chloride, diethyl aluminum bromide, ethyl aluminum sesquichloride, ethyl aluminum dichloride and the like.

The most preferred compounds are triethyl aluminum, diethyl aluminum chloride, and mixtures thereof.

Examples of the electron-donating compound in the present invention include ethyl acetate, e-caprolactone, methyl methacrylate, ethyl benzoate, ethyl p-anisate, methyl p-toluate, esters such as phthalic anhydride, or acid anhydrides, diesters, and the like. Examples thereof include ether compounds such as -n-butyl ether, diphenyl ether, and digram, and organic phosphorus compounds such as tri-n-butyl phosphite, triphenyl phosphite, and hexamethylene phosphoric triamide. In addition, ketones, amines, amides, thioethers, alkoxysilanes having a Si—O—C bond, or organosilicon compounds such as aryloxysilane can be used. The solid catalyst component may be preliminarily polymerized by treating with a small amount of olefin in the presence of an organoaluminum compound or an electron donating compound prior to the vapor phase polymerization. I don't care.

The copolymer (B) used in the composition of the present invention uses a very small amount of an α-olefin having 4 or more carbon atoms or ethylene as a comonomer. Examples of α-olefins having 4 or more carbon atoms include butene-1, pentene-1, hexene-1,
4-methylpentene-1 and the like may be used alone or in combination. Butene-1 is most preferable because it is difficult to liquefy when gas phase polymerization is carried out and a high partial pressure can be obtained.

The content of α-olefin having 4 or more carbon atoms in the copolymer (B) used in the composition of the present invention is 8 to 35 mol%,
% Is preferable, and 10 to 26 mol% is more preferable. Carbon number 4
If the above α-olefin content is below the lower limit, the effect of improving the low-temperature shrinkability of the shrink film is insufficient, which is not preferable, and if it is above the upper limit, the blocking resistance of the shrink film is poor. Moreover, the amount of solvent extraction increases, which is not preferable.

The ethylene content of the copolymer (B) used in the composition of the present invention is 5 mol% or less, preferably 3 mol% or less.

If the ethylene content exceeds the upper limit, the transparency of the shrinkable film deteriorates over time, which is not preferable. The reason for this is
Although it is not clear, the bleeding of the atactic component seems to be the cause.

The CXS of the copolymer (B) used in the composition of the present invention is 15 to
It is 70 wt%, preferably 1 to 50 wt%, more preferably 15 to 35 wt%.

If CXS is below the lower limit, the effect of improving the low-temperature shrinkability of the shrink film is insufficient, which is not preferable, and if it exceeds the upper limit, the blocking resistance of the shrink film is deteriorated.
Moreover, the amount of solvent extracted is large, which is not preferable.

The ΔHaze of the copolymer (B) used in the composition of the present invention is 5
% Or less is preferable, 4% or less is more preferable, and 3% or less is further preferable.

When the ΔHaze exceeds the upper limit, the transparency of the shrink film is deteriorated with time, and the blocking resistance is deteriorated, which is not preferable.

The solvent extraction amount of the copolymer (B) used in the composition of the present invention is not particularly limited, but is preferably 40 wt% or less,
20 wt% or less is more preferable.

If the solvent extraction amount is less than the upper limit, the solvent extraction amount of the composition can be increased even if the blending ratio of the copolymer (B) is increased at the time of blending with the copolymer (A) or the like. ， It is preferable because it has the advantage that it can be reduced. What the present inventor has discovered is that when the above-mentioned specific copolymer (A) is used, the solvent extraction amount as a composition becomes a value much smaller than the value obtained from the additivity of both. That's what it means.

The composition used in the present invention contains 5 to 90 wt% of the copolymer (A).
%, The copolymer (B) 95 to 10 wt% is blended, and the copolymer (A) is 10 to 85 wt% and the copolymer (B) is
90 to 15 wt% is preferable.

When the blending amount of the copolymer (A) exceeds the upper limit, the blending amount of the copolymer (B) has to be reduced, and as a result, low temperature shrinkability cannot be achieved, which is not preferable. If the blending amount of the copolymer (A) is less than the lower limit, the blending amount of the copolymer (B) must be increased, and the solvent extraction amount becomes large, which is not preferable.

The melt index (g / 10 minutes) of the composition formulated as described above is preferably 0.3 to 30 g / 10 minutes. If the melt index is below the lower limit, the extrusion processability will be poor, and if it is above the upper limit, the film processability will be poor, which is not preferable.

In the present invention, the above composition can be obtained by uniformly dispersing it by any known method. For example, an extrusion melt blending method, a Banbury blending method, and the like. It is also possible to obtain the above composition by a so-called multi-stage polymerization method in which the polymerization conditions are changed stepwise.

The composition of the present invention may be blended with small amounts of other polymeric materials. Further, additives such as antistatic agents, antiblocking agents, lubricants, stabilizers and nucleating agents can be added.

As a method of film-forming the composition of the present invention, known processing methods such as T die casting method and water cooling inflation method can be adopted. Moreover, as a method of performing the stretching treatment,
Known uniaxial stretching methods such as roll stretching, roll rolling and tenter transverse uniaxial stretching, and known biaxial stretching methods such as tenter biaxial stretching and tubular biaxial stretching can be employed. The stretching temperature is from room temperature to the melting point (main peak) of the composition or less, but in order to improve the low temperature shrinkability of the obtained film, it is preferably as low as possible within the range where uniform stretching can be performed. The draw ratio is 2-10 for uniaxial stretching.
In the case of biaxial stretching, each axis is preferably 1.5 to 10 times. In this case, the MD (longitudinal direction) and TD (horizontal direction) draw ratios do not necessarily have to be balanced, and can be arbitrarily selected according to each application.

The data and evaluations in the examples and comparative columns were performed according to the following method.

(1) α-Olefin content in copolymer It was determined from the mass balance during polymerization. The content of butene-1 was further quantified by an ordinary method from the characteristic absorption at 770 cm ^-1 using an infrared spectrophotometer.

In the measurement with the infrared spectrophotometer, a propylene-butene-1 copolymer was quantified by preparing a calibration curve from the quantitative value by ¹³ C-NMR.

(2) copolymer of 732 cm ^-1 using an ethylene content infrared spectrophotometer, was quantified by a conventional method from the characteristic absorption of 720 cm ^-1. The infrared spectrophotometer was used for quantification by preparing a calibration curve based on the quantified values of ¹⁴ C-labeled ethylene copolymer measured by radiation.

(3) Melt index (MI) Complies with ASTM-D1238.

(4) Vicat softening point (VSP) Compliant with ASTM-D1525.

(5) Cold xylene soluble part (CXS) Dissolve 5 g of polymer in 500 ml of xylene, and then slowly cool to room temperature. Then, after standing in a bath at 20 ° C. for 4 hours, the mixture is filtered, the filtrate is concentrated, dried, dried and weighed.

(6) Intrinsic Viscosity ([η]) Tetralin was measured at 135 ° C. according to a conventional method by changing the concentration to 0.4, 0.2, 0.133 and 0.1 g / dl at 4 points.

(7) Create a press sheet of △ Haze copolymer with a thickness of 100μ, and
It was expressed as the difference between the haze after annealing for a certain time and the haze before the annealing.

(8) Solvent extraction amount This is the n-hexane extraction amount at 50 ° C specified by FDA §177 ・ 1520.

(9) Haze value (Haze) According to ASTM-D1003.

(10) Heat shrinkage A film specimen with a 5 cm square is immersed in a glycerin bath at a predetermined temperature for 10 seconds to measure the MD and TD shrinkage.

(11) Blocking Put two films on top of each other and condition them at 35 ° C for 24 hours with a load of 7 kg per 100 cm ² area.

Then, after leaving it at 23 ℃ for 30 minutes, the two films were peeled in a direction perpendicular to the film surface at a load increasing rate of 10 g / min, and the maximum load (g) at that time was calculated and converted per 100 cm ^{2 of} film area. To represent.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples as long as the gist thereof is not exceeded.

Example 1 (1) Synthesis of solid product A flask having an internal volume of 500 ml equipped with a stirrer and a dropping funnel was replaced with argon, and then 83 ml of n-heptane, 16.1 ml of titanium tetrachloride, and 51.0 ml of tetra-n-butoxytitanium. Add to a flask and keep the temperature in the flask at 20 ℃ while stirring.
Kept at. A solution consisting of 162.1 ml of n-heptane and 37.8 ml of diethylaluminium chloride was added to the flask at a temperature of
While maintaining the temperature at 20 ° C., the solution was gradually added dropwise from the dropping funnel over 3 hours. After the dropping was completed, the temperature was raised to 50 ° C. and the mixture was stirred for 1 hour. The mixture was left standing at room temperature for solid-liquid separation, washed 4 times with 20 ml of n-heptane, and dried under reduced pressure to give 64.7 g of a reddish brown solid product.
Got

(2) Synthesis of prepolymerized solid After a flask with a capacity of 300 ml equipped with a stirrer was replaced with argon, n-heptane 241 ml, triethylaluminum 0.34
g and 19.7 g of the solid product prepared in the above (1) were charged into a flask, and the temperature was kept at 50 ° C. Then, while stirring, ethylene was maintained at a partial pressure of 0.2 kg / cm ² and gradually fed into the suspension at 50 ° C. for 20 minutes to carry out a prepolymerization treatment. After the treatment, solid-liquid separation was performed, washing with 50 ml of n-heptane was repeated twice, and then drying under reduced pressure. Prepolymerization amount is 1g of solid product
The weight of the polymer was 0.09 g.

(3) Synthesis of solid catalyst component After replacing the flask with an internal volume of 100 ml with argon, 12.1 g of the prepolymerized solid prepared in (2) above and 42.3 ml of n-heptane were put into the flask, and the temperature in the flask was adjusted to 30. ℃
Kept at. Next, 14.4 ml of di-iso-amyl ether was added, and the mixture was treated at 30 ° C for 1 hour and then heated to 75 ° C. 75 ° C
Then, 15.7 ml of titanium tetrachloride was added and the reaction was carried out at 75 ° C for 1 hour. After solid-liquid separation, washing with 50 ml of n-heptane was repeated 4 times, followed by vacuum drying to obtain a solid component.

Further, after replacing the flask having an inner volume of 100 ml with argon, 9.9 g of the above solid component and 38 ml of n-heptane were charged into the flask and the temperature inside the flask was kept at 30 ° C. Next, 8.5 ml of di-iso-amyl ether was added, and the mixture was treated at 30 ° C for 1 hour and then heated to 75 ° C. Titanium tetrachloride (11.5 ml) was added at 75 ° C, and the reaction was carried out at 75 ° C for 1 hour. After solid-liquid separation, washing with 50 ml of n-heptane was repeated 4 times, followed by drying under reduced pressure to obtain a solid catalyst component.

(4) Copolymerization (Copolymer (B)) Copolymerization of propylene and butene-1 was carried out using a fluidized bed reactor equipped with a stirrer and having an internal volume of 1 m ³ . First, 60 parts of propylene-butene-1 copolymer particles for catalyst dispersion were placed in a reactor.
kg was fed, then the reactor was purged with nitrogen and then with propylene. Pressure up to 5 kg / cm ² G with propylene, 80 m
Circulating gas was supplied from the bottom of the reactor at a flow rate of ³ / hr to keep the polymer particles in a fluidized state, and then the catalyst shown below was supplied to the reactor. As the catalyst components (b) and (c), a solution diluted with heptane was used.

(A) Solid catalyst component 21g (b) Diethylaluminum chloride 156g (c) Triethylaluminum 22g (d) Methyl methacrylate 15g Then hydrogen, propylene, butene-1 so that the hydrogen concentration is 1.7vol%, butene-1 29vol%. Supply 10 kg / cm
^The pressure was raised to ² G and the temperature of the fluidized bed was adjusted to 70 ° C to initiate polymerization. Hydrogen, propylene and butene-1 were supplied so that the concentrations of hydrogen and butene-1 and the pressure were kept constant during the polymerization. When the amount of polymerization reached 75 kg, 60 kg of polymer particles were left in the reactor for catalyst dispersion for the next polymerization, the remaining polymer particles were transferred to a stirring and mixing tank, and 210 g of propylene oxide and 100 g of methanol were added. And treated at 80 ℃ for 30 minutes. Then, it was dried to obtain a white powdery polymer. The same polymerization was repeated 3 times, and the physical properties of the finally obtained polymer (copolymer (B)) were measured. Butene-1 content is
20.3 mol%, CXS was 23.9%, △ Haze was 0.9%, the solvent extraction amount was 7.3%, and the intrinsic viscosity was 1.8 dl / g.

(5) Composition Preparation Copolymer (A) Sumitomo Noblene RW160 was used. RW160 containing ethylene
The abundance is 4.8 wt%, the Vicat softening point is 118 ° C,
Melt index is 8.8g / 10min, CXS is 4.3%.
It was.

40 wt% of the copolymer (A) and 60 wt% of the copolymer (B) obtained in (4) were subjected to uniform melt blending with a 65φ extruder. BHT 0.1 part was added as an antioxidant, fine powder aluminosilicate 0.4 part was added as an anti-blocking agent, and erucic acid amide 0.2 part was added as a lubricant.

About this resin composition, a 400μ sheet was obtained by the pressing method, and then a 90-square sheet was sampled under the following conditions:
An axially stretched film was obtained.

Stretching machine: Desktop biaxial stretching machine manufactured by Toyo Seiki Temperature: 80 ℃ Preheating time: 3 minutes Stretching ratio: MD5 times, TD5 times Stretching speed: 15m / min (simultaneous biaxial stretching) About 15μ thick film obtained above The physical properties of and are shown in Table 1 together with the physical properties of the composition. The shrinkage ratio is shown as the average value of MD and TD.

This biaxially stretched film was made of a resin with a small solvent extraction amount, and was excellent in transparency, low-temperature shrinkage, and blocking resistance.

Example 2 Using the same copolymers (A) and (B) as used in Example 1, except that the blending ratio in the composition preparation and the stretching temperature were changed to 90 ° C., A biaxially stretched film was obtained under the same conditions as in Example 1. The blending ratio, the physical properties of the composition, and the physical properties of the film are shown in Table 1. This biaxially stretched film had good special properties as in Example 1.

Examples 3 and 4 (1) Polymerization of copolymer (B) The same polymerization conditions as in Example 1 were used, except that the catalyst system used in Example 1 was used and the amount of butene-1 charged was changed. To obtain a copolymer.

The obtained copolymer (B) had a butene-1 content of 15.8 mol%, CXS of 19.5 wt%, △ Haze of 0.4%, and solvent extraction of 6.2.
%, The intrinsic viscosity was 1.8 dl / g.

(2) Preparation of composition and production of stretched film Copolymer (A) Sumitomo Noblene FL6711N was used. FL6711N
Content is 6.2wt%, Vicat softening point is 109 ℃, melt
The index was 5.5g / 10min and CXS was 9.5wt%.

Using the above copolymer (A) and copolymer (B), the mixing ratio in the composition preparation and the stretching temperature could be changed to 90 ° C. A stretched film was obtained.

The blending ratio, the physical properties of the composition, and the physical properties of the film are shown in Table 1. These biaxially stretched films had good properties as in Example 1.

Example 5 (1) Polymerization of Copolymer (B) Using the catalyst system used in Example 1, except that the amount of butene-1 charged was changed and the polymerization pressure was changed to 7 kg / cm ² G, A copolymer was obtained under the same polymerization conditions as in Example 1.

The content of butene-1 in the obtained copolymer (B) was 24.5 mol%, CXS was 33.5 wt%, △ Haze was 1.4%, and the solvent extraction amount was 14.5%.
%, The intrinsic viscosity was 2.0 dl / g.

(2) Preparation of composition and production of stretched film The same copolymer (A) as that used in Example 1 was used.

Biaxially stretched film under the same conditions as in Example 1 except that the blending ratio in the composition preparation and the stretching temperature were changed to 90 ° C. by using the copolymer (A) and the copolymer (B). Got

The blending ratio, the physical properties of the composition, and the physical properties of the film are shown in Table 1. This biaxially stretched film had good properties as in Example 1.

Example 6 (1) Polymerization of Copolymer (B) The same catalyst system was used except that triethylaluminum was removed from the catalyst system used in Example 1 and the amount of methyl methacrylate was reduced to 8 g. Using butene-1
A copolymer was obtained under the same polymerization conditions as in Example 1 except that the charged amount was changed and ethylene was newly introduced. The resulting copolymer (B) had a butene-content of 16.1 mol% and ethylene. Content is 2.0 mol%, CXS is 24.5 wt%, ΔHa
ze is 1.3%, solvent extraction is 12.5%, intrinsic viscosity is 2.0 dl /
It was g.

(2) Preparation of composition and production of stretched film The same copolymer (A) as that used in Example 1 was used.

Biaxially stretched film under the same conditions as in Example 1 except that the blending ratio in the composition preparation and the stretching temperature were changed to 90 ° C. by using the copolymer (A) and the copolymer (B). Got

The blending ratio, the physical properties of the composition, and the physical properties of the film are shown in Table 1.

This biaxially stretched film had good properties as in Example 1.

Comparative Example 1 The copolymer (B) itself used in Example 3 was used.

A biaxially stretched film was obtained under the same conditions as in Example 1 except that the stretching temperature was changed to 90 ° C. In addition, stretching below 90 ° C was impossible. The physical properties of the film are shown in Table 1. This biaxially stretched film was inferior in blocking resistance and in that it was made of a resin having a large amount of solvent extraction.

Comparative Example 2 (1) Preparation of Composition and Production of Stretched Film Copolymer (A), Copolymer (B) The same as in Example 1 was used.

A biaxially stretched film under the same conditions as in Example 1 except that the blending ratio in the composition preparation and the stretching temperature were changed to 110 ° C. by using the copolymer (A) and the copolymer (B). Got Note that stretching below 110 ° C was impossible.

The blending ratio, the physical properties of the composition, and the physical properties of the film are shown in Table 1.

This biaxially stretched film was unfavorable because of its low temperature shrinkage.

Comparative Example 3 (1) Preparation of composition and production of stretched film Copolymer (A) Sumitomo Noblene RW140 was used. RW140 containing ethylene
The abundance is 3.7 wt% and the Vicat softening point is 125 ° C.
The melt index is 8.3g / 10 minutes, and CXS is 3.8.
%.

 Copolymer (B) The same as in Example 1 was used.

A biaxially stretched film under the same conditions as in Example 1 except that the blending ratio in the composition preparation and the stretching temperature were changed to 110 ° C. by using the copolymer (A) and the copolymer (B). Got Note that stretching below 110 ° C was impossible. The blending ratio, the physical properties of the composition, and the physical properties of the film are shown in Table 1.

This biaxially stretched film was unfavorable because of its poor low temperature shrinkability.

Comparative Example 4 (1) Preparation of Composition and Production of Stretched Film Copolymer (A) The same as in Example 1 was used.

Copolymer (B) Obtained by a slurry polymerization method using n-heptane as a solvent, which is a propylene-butene-1 copolymer from which components soluble in n-heptane have been removed and which contains butene-1. The amount is 15.1 mol%, CXS is 10.1 wt%, △ Haze is 0.5%, solvent extraction is 3.0 wt%, and intrinsic viscosity is 1.9 dl / g.

A biaxially stretched film under the same conditions as in Example 1 except that the blending ratio in the composition preparation and the stretching temperature were changed to 100 ° C. by using the copolymer (A) and the copolymer (B). Got Note that stretching below 100 ° C was impossible. The blending ratio, the physical properties of the composition, and the physical properties of the film are shown in Table 1.

This biaxially stretched film had poor low temperature shrinkability and was not preferred.

Comparative Example 5 (1) Preparation of composition and production of stretched film Copolymer (A) Sumitomo Noblene RW120 was used. RW120 containing ethylene
The abundance is 2.3 wt% and the Vicat softening point is 137 ° C.
The melt index is 9.1g / 10 and CXS is 3.2%.
is there.

 Copolymer (B) Mitsui Petrochemical Tuffmer XR110T propylene-bute
N-1 random copolymer was used. Tuffmer used
XR110T has a butene-1 content of 26.5 mol% and CXS of 62 wt.
%, △ Haze is 2.5%, solvent extraction is 69wt%, intrinsic viscosity
Is 1.8 dl / g.

A biaxially stretched film under the same conditions as in Example 1 except that the blending ratio in the composition preparation and the stretching temperature were changed to 90 ° C. by using the copolymer (A) and the copolymer (B). Got
The blending ratio, the physical properties of the composition, and the physical properties of the film are shown in Table 1.

This biaxially stretched film was not preferable because it was made of a resin having a large solvent extraction amount as a raw material and was inferior in blocking resistance.

Comparative Example 6 A biaxially stretched film was obtained under the same conditions as in Example 1, except that the copolymer (A) used in Example 1 was used and the stretching temperature was changed to 110 ° C. Note that stretching below 110 ° C was impossible. The physical properties of the film are shown in Table 1.

This biaxially stretched film had poor low temperature shrinkability.

Comparative Example 7 A biaxially stretched film was obtained under the same conditions as in Example 1, except that the copolymer (A) used in Example 3 was used and the stretching temperature was changed to 100 ° C. Note that stretching below 100 ° C was impossible. The physical properties of the film are shown in Table 1.

This biaxially stretched film had poor transparency and poor low temperature shrinkability.

<Effects of the Invention> The resin composition of the present invention has excellent low-temperature shrinkability, and
A shrink-wrapping film made of a raw material with excellent transparency and blocking resistance, and with a small amount of solvent extracted was obtained.

Claims (3)

[Claims] 1. A propylene random copolymer (A) having a comonomer content of 4 to 15 wt% Vicat softening point of 122 ° C. or less and a cold xylene-soluble portion of 15 wt% or less, and (B) A copolymer of propylene and an α-olefin having 4 or more carbon atoms, or propylene, an α-olefin having 4 or more carbon atoms, and ethylene, wherein the α-olefin having 4 or more carbon atoms has a content of 8 ~ 35 mol% ethylene content 5 mol% or less The cold xylene-soluble part is composed of two components (A) and (B) of 15 to 70 wt%, and (A) 5 to
A film for shrink wrapping, which is obtained by forming a resin composition containing 90 wt% and (B) 95 to 10 wt% and then stretching the resin composition in at least a uniaxial direction. 2. The shrink-wrapping film according to claim 1, wherein the component (B) has ΔHaze of 5% or less. 3. The shrink-wrapping film according to claim 1, wherein the solvent extraction amount of the component (B) is 40 wt% or less.