JP2000063597A - Soft polyolefin resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition having good heat resistance and good flexibility and having excellent transparency, when processed into a film, etc. SOLUTION: This soft polyolefin resin composition contains (A) 100 pts.wt. of a polypropylene-based polymer having a melting point of 15-80 J/g measured with a differential scanning calorimeter(DSC) and a melting peak temperature(Tpm) of >150 deg.C and (B) 30-400 pts.wt. of a poly.1-butene-based polymer, and a multi-layered film contains a layer comprising the same.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a soft polyolefin resin composition having both heat resistance and flexibility, and a film using the same. In particular, the present invention relates to a resin composition for film suitable for stretch packaging and a film using the same.

[0002]

2. Description of the Related Art Foods such as fruits and vegetables, fresh fish, meat, prepared foods,
There are some required characteristics for a film (referred to as a stretch wrapping film) used when stretch-wrapping a product directly or placed on a plastic tray or the like.
Specifically, a) excellent stretchability (small elongation load and large elongation at break), b) film does not tear during packaging (high impact strength), c) excellent heat sealability, D) It has a display effect (the film is transparent, has gloss, and has good anti-fogging property).

As a film satisfying these required characteristics, JP-A-9-174774 discloses that both surface layers of ethylene-vinyl acetate copolymer (EVA) and the like, a stretching auxiliary layer, and crystalline polybutene-1 and a homotype. A polyolefin resin multilayer stretch film including a composition layer (heat resistant layer) with crystalline polypropylene has been proposed. This film is made of EVA having a melting point of about 90 ° C. so that the surface layer can be heat-sealed at a wide lower temperature limit, and has a high crystallinity and a melting point of 165 so that the heat-resistant layer can be heat-sealed at a wide upper temperature limit. It uses isotactic polypropylene at about ℃. Therefore, other commercially available films have a heat sealable temperature range of about 20 to 30 ° C., while this film has a heat sealable temperature of 55 ° C.
Excellent in degree and heat sealability. Also, 100% elongation load, which is a measure of stretchability, is 250 in the machine direction (MD).
~ 550g / cm width, transverse direction (TD) 50-200g
With a width of about / cm, it is suitable for the projecting type packaging machine at the time of proposal, for example, A-18X and A-18K manufactured by Fujikikai.

However, hand wrapping and highly stretchable wrapping type machines, which have recently become popular rapidly,
For example, Ishida / Wmini-Zero series, Teraoka Seikosha / AW3600, FX3600, TEC / ELI
It was often unsuitable for XA etc. On the other hand, in order to achieve both heat resistance and stretchability, the heat-resistant layer is a composition layer containing a propylene-α / olefin random copolymer as a main component, and EVA layers are laminated on both surfaces of the composition layer to form three layers. Structured film (Japanese Patent Publication No. 4-50904)
Or a stretch film comprising a composition layer in which a copolymer of a vinyl aromatic compound and a conjugated diene or a hydrogenated derivative thereof is blended with a propylene random polymer (JP-A-4-270745 and JP-A-8-119319).
No. gazettes, etc.) are proposed.

[0005]

However, the above-mentioned heat-resistant layer composition has a melting peak temperature (Tp) as a propylene-based resin in order to impart transparency and gloss to the film.
Only those having m) of less than 150 ° C. and low crystallinity can be put to practical use. Therefore, the conventional composition described above could only provide a film having poor heat resistance as compared with the conventional film.

[0006] The present invention is a heat resistance of a film excellent in stretchability while maintaining the high level of impact resistance, high heat sealability and high displayability (specifically, transparency, glossiness and antifogging property) of the conventional level. An object is to provide a soft polyolefin resin composition having excellent heat resistance, which is suitable as a layer, and a film using the same.

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to achieve the above objects, and as a result, have accomplished the present invention. That is, the present invention (1) has a heat of fusion of 15 to 80 J measured by a differential scanning calorimeter (hereinafter referred to as DSC).
100 g by weight of polypropylene-based polymer (A) having a melting peak temperature (Tpm) of 150 ° C. or higher and poly.
1-butene polymer (B) 30 to 400 parts by weight of a soft polyolefin resin composition, (2) heat-resistant layer (H
Layer) has a heat of fusion measured by DSC of 15 to 80 J
100 g by weight of polypropylene-based polymer (A) having a melting peak temperature (Tpm) of 150 ° C. or higher and poly.
Melt peak temperature measured by DSC in addition to a multilayer film containing a soft polyolefin resin composition layer consisting of 1 to butene polymer (B) 30 to 400 parts by weight, (3) heat resistant layer (H layer) The multilayer film according to (2) above, which has both surface layers (S layers) containing a polyolefin resin having a (Tpm) of 100 ° C. or lower.

The present invention will be described in detail below. The composition of the present invention comprises a polypropylene-based polymer (A) and a poly / 1-butene-based polymer (B) having specific thermal properties. The polypropylene-based polymer (A) having the specific thermal characteristics is a propylene homopolymer having an isotacticity index of 90 or more, or a random copolymer of propylene and ethylene or an α-olefin having 4 or more carbon atoms ( Hereinafter, abbreviated as "random PP"), the "heat resistant component" having a melting peak temperature (Tpm) measured by DSC of 150 ° C or higher and the heat of fusion measured by DSC are 15 to 8
A so-called block copolymer or a propylene homopolymer having an isotacticity index of less than 90 consisting of "amorphous and flexible component" in a ratio of 0 J / g (hereinafter, both are collectively referred to as block PP). ).

Generally, the block PP is rarely used for film applications. The reason is high crystallinity and a melting point of 160.
This is because the heat-resistant component in the block PP is crystallized when it is formed into a film, and only a film having inferior transparency can be obtained, as in the case of isotactic polypropylene at about ° C. Even if the melt-extrusion is followed by rapid cooling to suppress the crystallization of the heat-resistant component, the block PP has an amorphous and flexible component island dispersed in the sea of the heat-resistant component in the order of several μm to sub-μm. When the film is stretched to form a film, the surface of the film is roughened, and as a result, the film tends to be opaque.

Therefore, the present inventors utilize the heat-resistant and flexible property of "polypropylene polymer (A) having specific thermal properties" = "specific block PP",
As a result of extensive studies on a composition that can give a transparent film when formed into a film, the above composition was found. The block PP referred to here is not only a block copolymer of propylene and an α-olefin having a carbon number other than 3, but also a homopolymer of propylene, each part of isotactic PP and atactic PP. A polymer having a fine domain structure can be included in the category of the substantial block PP due to the structure. In the latter case, boiling n
A propylene homopolymer having an isotactic index of less than 90 determined as a heptane-insoluble matter, more preferably a propylene homopolymer having an isotactic index of 55 to 85, and one example of this is JP Patent No. 253
It is disclosed in Japanese Patent No. 4370.

A concrete example will be described below with reference to a first embodiment.
Run. No. 1 film and Comparative Example 1, Run. N
o. In comparison with the film of No. 2, as shown in Table 1,
Run. Using a composition comprising a polypropylene-based polymer (A) having a specific thermal property and a poly / 1-butene-based polymer (B) in a heat-resistant layer. No. The transparency of film No. 1 is ○
(Haze = 1.8%) ◎ (GLOSS = 13)
0%), which was excellent in optical characteristics, while Run. N
o. 1 in which only the polypropylene-based polymer (A) used in No. 1 was used in the heat-resistant layer. No. The transparency of film No. 2 is ×
(Haze = 3.8%), gloss is x (GLOSS = 1)
(05%), the optical characteristics were clearly inferior.

Further, in place of the poly-1-butene polymer (B), an extremely low density ethylene-α-olefin copolymer was used in Comparative Example 1, Run. No. In film 3
Haze = 5.2%, GLOSS = 95%, and the film was inferior in transparency as compared with the case where only the polypropylene polymer (A) was used. Furthermore, Comparative Example 1 using a polystyrene-based hydrogenated block copolymer instead of the poly-1-butene-based polymer (B), Run. No. As shown in Table 1, in the film of No. 4, the impact strength, which is one of the characteristics of the polypropylene-based polymer (A), was reduced, and the tear strength and impact resistance were reduced, resulting in wrapping property. It was a poor film.

From the above, a composition comprising a polypropylene-based polymer (A) having a specific thermal property and a poly-1-butene-based polymer (B) has a polypropylene-based polymer having a specific thermal property. It can be seen that the composition takes advantage of the heat-resistant and flexible property of (A), and when it is formed into a film, a transparent film is obtained. Poly 1-
The amount of the butene-based polymer (B) is required to be in a range in which the transparency improving effect is exhibited and the polypropylene polymer (A) is not impaired in properties such as heat resistance and flexibility. (A) Poly 1-based on 100 parts by weight
The butene polymer (B) needs to be 30 to 400 parts by weight, and preferably 50 to 200 parts by weight.

If a concrete example is shown, the second embodiment will be described later.
Run. No. 7 film and Comparative Example 2, Run. N
o. In comparison with the film of No. 9, as shown in Table 2,
Ru in which the amount of the poly-1-butene polymer (B) is 33 parts by weight based on 100 parts by weight of the polypropylene polymer (A).
n. No. The film No. 7 has a transparency of ○ (Haze = 2.
0%) The gloss was good (GLOSS = 125%), which was excellent in optical characteristics, while the same proportion was 25 parts by weight Ru.
n. No. The transparency of film No. 9 is Δ (Haze = 3.
0%), and the gloss was inferior as Δ (GLOSS = 110%).

In Example 2, Run. No. 8 film and Comparative Example 2, Run. No. In comparison with the film of No. 10, as shown in Table 2, the poly.1-butene-based polymer (B) was 400 parts by weight based on 100 parts by weight of the polypropylene-based polymer (A). No. The same ratio as in the film of No. 8 was 566 parts by weight in Run. No. 10
Film was inferior in impact resistance and heat resistance during heat sealing (heat sealable maximum temperature: T2 = 130 ° C.).

From the above, it can be seen that the poly-1-butene polymer (B) needs to be 30 to 400 parts by weight based on 100 parts by weight of the polypropylene polymer (A). Next, the polypropylene polymer (A) used in the present invention has a heat of fusion of 15 to 80 as measured by DSC.
The melting peak temperature (Tpm) is 150 ° C. or higher at J / g.

As described above, polypropylene polymer (A)
Is a so-called block PP. From the viewpoint of heat resistance, the heat of fusion must be 15 J / g or more and Tpm must be 150 ° C. or more, and the heat of fusion is 80 J / g or less from the viewpoint of flexibility. Need to be As a specific example, Run. No. 11 film and Comparative Example 3, Run. No. In comparison with the film of No. 13, as shown in Table 3, there is almost no difference in melting point, but the heat of fusion of the polypropylene-based polymer (A) is 23.7 J / g.
(Tpm = 155 ° C.) Run. No. The film No. 11 had a heat sealing property of ◯ (T2 = 140 ° C.), which was at a practical level, whereas the heat of fusion of the polymer (A) was 1
Run. 3.9 J / g (Tpm = 153 ° C.). N
o. The film of No. 13 has a heat sealability of × (T2 = 13
It was inferior in heat resistance to 0 ° C. In particular, the difference becomes clear as the heat-sealing time becomes longer. For example, when the heat resistance during heat-sealing is evaluated by setting the sealing time to 10 seconds, Run. No. Film 11 has T2 of 135 ° C
(The heat sealability is Δ: a practical level depending on the conditions), while the Run. No. In the film of No. 13, there was no heat sealable temperature condition.

In Comparative Example 3, Run. No. 15, the heat of fusion of the propylene-based polymer (A) was 61.9 J / g and R
un. No. Greater than 11, but with Tpm of 139 ° C and 15
It was lower than 0 ° C. and was inferior in heat sealability as shown in Table 3 (T2 = 130 ° C.). In Example 3, Run. N
o. From the viewpoint of heat resistance at the time of heat sealing of the film, the heat of fusion of the polypropylene polymer (A) is 15 J /
It can be seen that g or more and Tpm are required to be 150 ° C. or more.

Further, as will be described later in Example 3, Run. No.
12 film and Comparative Example 3, Run. No. Comparing with No. 14, the melting point of polypropylene-based polymer (A) is almost the same, but the heat of fusion of polypropylene-based polymer (A) is 77.5 J / g (Tpm = 16).
3 ° C. Run. No. As compared with the film of No. 12, the heat of fusion of the polymer (A) was 84.7 J / g (Tpm = 165
C.). No. The No. 14 film was poor in flexibility to the polypropylene polymer (A). Therefore, the resulting film had a small elongation at break in a tensile test and a small tear strength, and thus was a film having a poor wrapping property.

In Example 3, Run. No. From the viewpoint of balance of stretchability and impact strength, the heat of fusion of the polypropylene polymer (A) is 80 J from the film of No. 12
It can be seen that it is necessary to be less than / g. From the above, the heat of fusion of the polypropylene polymer (A) of the present invention is 15 to 80 J / g, preferably 20 to 80 J.
/ G, and more preferably 30 to 75 J / g.

The melting peak temperature (Tpm) is 150 ° C. or higher from the viewpoint of heat resistance of the composition, preferably Tp.
m is 155 degreeC or more. Here, the heat of fusion and the melting peak temperature (Tpm) of the polypropylene-based polymer (A) were measured using DSC-7 manufactured by Perkin Elmer Co., Ltd.
Regarding the heat of fusion, the amount of sample was measured in accordance with JIS-K7122 under the conditions of a sample amount of 5 to 10 mg and a temperature rising rate of 10 ° C./min, and the peak was obtained from the highest temperature. The melting peak temperature (Tpm) Was measured in accordance with JIS-K7121 with a sample amount of about 5 mg and a temperature rising rate of 10 ° C./min, and was determined from the peak that appeared at the highest temperature.

A resin satisfying the above characteristics has a Tpm of 1
Highly crystalline polypropylene component (a
1) and an amorphous and flexible component (a2), which are polymerized in a single-stage or multi-stage reactor, and a1 and a
It does not include those obtained by mechanically melt-mixing 2. More specifically, as a1, highly crystalline, isotactic propylene homopolymer having a melting point of about 160 ° C., or propylene containing ethylene, an α-olefin having 4 or more carbon atoms, or the like.
A random copolymer obtained by copolymerizing about 7 mol% or less may be used.

Further, a2 is an amorphous and / or semi-crystalline atactic propylene homopolymer or a copolymer of propylene and ethylene or an α-olefin having 4 or more carbon atoms, and generally has a weight average molecular weight of a1. Of about 1/10 or more, preferably about half or more, more preferably about 1 or more. If you show a concrete example,
"Adf manufactured by Monterey's Catalloy process
“Plex”, “PER” by Tokuyama Corporation, “NEWCON” by Chisso Corporation, “Idemitsu TPO” by Idemitsu Petrochemical Co., Ltd., and the like.

Among these, the difference (T) between the melting peak temperature (Tpm) measured by DSC and the extrapolation melting start temperature (Tim)
It is preferable that pm-Tim) is 12.5 ° C or higher. Here, the extrapolation melting start temperature (Tim) is JIS-K.
According to 7121, the sample amount is about 5 mg, and the heating rate is 10
It was measured under the condition of ° C / min, and the peak was expressed at the highest temperature. The peaks or shoulders within the range of 10 ° C. from the highest temperature peak were collectively considered as one peak, and the peak or shoulder on the lowest temperature side among the peaks or shoulders was extrapolated based on the reference.
The extrapolation melting start temperature (Tim) is shown as Onset temperature in DSC-7 manufactured by Perkin Elmer.

In the polypropylene-based polymer (A) having a lower Tim relative to Tpm, in other words, a broader low temperature side of the melting peak, the amorphous component is compatible with the crystalline component at the molecular level, and It is believed that the high melting point and high crystalline component and the flexible and amorphous component do not simply form a sea-island structure, but interact at the molecular level. The parts that worked together,
Alternatively, it can be inferred that there is a transition area part between them. In forming this portion, it is considered advantageous that the two have similar chemical structures. For example, when the highly crystalline component is a propylene homopolymer, the flexible amorphous component also has propylene and a carbon number other than 3. A propylene homopolymer is more preferable than a copolymer with α-olefin.

Such polypropylene polymer (A)
Improves the dispersibility in the poly-1-butene-based resin (B), thereby significantly improving the optical properties of the composition. If a specific example is shown, Ru, which will be described later in Example 4,
n. No. 18 and Examples, Run. No. 21. In comparison with Run No. 21, Run.Tm using the polypropylene-based polymer (A) having Tpm-Tim of 12.2 ° C. No. No. 18, Haze was 1.8%, and the film had a hazy appearance, whereas Run. Using a polypropylene-based polymer (A) having Tpm-Tim of 16.4 ° C. N
o. In No. 21, the transparency was remarkably excellent with Haze of 0.8%, and there was a clear feeling.

It should be noted that in addition to the polypropylene polymer (A) and the poly-1-butene resin (B), E
It is also excellent in transparency even in a composition in which VA, an ethylene-α / olefin copolymer, etc. are blended. Example 6, Run. No. 24, Tpm
40% by weight of polypropylene-based polymer (A) having a Tim of 16.4 ° C., 22% by weight of poly / 1-butene-based resin (B), 13% by weight of EVA, ethylene-α / olefin copolymer The film having a heat resistance of a composition containing 25% by weight of HASE was 0.9% in HAZE and the film had a clear feeling.

Looking at the compositions of the above examples comprising such a polypropylene polymer (A) and a poly-1-butene resin (B), Tpm-Tim is 1
Ru of 40% by weight of polypropylene polymer (A) and 60% by weight of poly-1-butene resin (B) at 2.2 ° C
n. No. 18 compositions have Tpm-Tim of 11.5 ° C.
On the other hand, 40% by weight of the polypropylene-based polymer (A) having a Tpm-Tim of 16.4 ° C. and 60% by weight of the poly-1-butene-based resin (B) in Run. No. The composition of 21 has a Tpm-Tim of 12.9 ° C. Thus, comparing Tpm-Tim of the polypropylene-based polymer (A), Tpm-Tim of the composition of 40% by weight of the polypropylene-based polymer (A) and 60% by weight of the poly-1-butene-based resin, Tpm-Tim The polypropylene-based polymer (A) having a larger value has a larger degree of change when the poly / 1-butene-based resin (B) is mixed (the degree of change of Run. The degree of change of 0.21 is 3.
5 ° C.), suggesting that the interaction between the polypropylene-based polymer (A) and the poly-1-butene-based resin (B) is greater, and from that also the polypropylene-based polymer having Tpm-Tim of 12.5 ° C. or higher. It is inferred that the film made of the composition of (A) and the poly-1-butene resin (B) has further excellent optical characteristics.

Next, the polypropylene-based polymer (A) of the present invention has a melt flow rate (MFR: 230 ° C.,
2.16 kg) is preferably 0.1 to 100 g / 10 minutes, more preferably 0.5 to 100 g / 10 minutes. The extrusion load tends to increase as the MFR decreases, and the resulting film has a tear strength in the longitudinal direction (M
The balance between D) and the lateral direction (TD) tends to be poor (weak in MD and strong in TD). When MFR is large, the balance between tear strength MD and TD tends to be good, but when it is too large, the melt tension during extrusion tends to be too small and stable tearing tends to be impossible. Particularly, in the double bubble method adopted in Examples 4 to 6 described later, 20 to 100 g / 10 min is most preferable.

Specific examples of the poly-1-butene polymer (B) include 1-butene homopolymer, 1-butene and ethylene, propylene, and α-olefins having 5 or more carbon atoms. Examples thereof include polymers, and of these, a poly-1-butene-based polymer having a melting peak temperature of 110 ° C. or less in which 4 mol% or more of a comonomer is copolymerized is preferable. The poly-1-butene-based polymer (B) has a melt index (MI: 190).
C., 2.16 kg) is preferably 0.1 to 50 g / 10 minutes, more preferably 0.5 to 50 g / 10 minutes for the same reason as the above polypropylene-based polymer (A), more preferably double bubbles. In the method, 2 to 10 g / 10 minutes is most preferable.

The composition of the present invention includes EVA, ethylene / α-olefin copolymer, hydrogenated terpene resin, in addition to the polypropylene polymer (A) and the poly-1-butene polymer (B). A hydrogenated cyclopentadiene-based resin, a petroleum resin, a copolymer of an aromatic compound and a conjugated diene, or a hydrogenated product thereof may be blended. Hydrogenated products of copolymerization of an aromatic compound and a conjugated diene include a hydrogenated conjugated diene portion and a hydrogenated aromatic compound (ring hydrogenation). It is preferable that the refractive index of the polyolefin and the compatibility thereof are close to each other so that the composition and the film having high transparency can be obtained.

The heat of fusion of the composition measured by DSC is preferably 7 J / g to 35 J / g, more preferably 8 to 35 J / g. If it is less than 7 J / g, heat resistance and elastic modulus of the composition are insufficient, and if it is 35 J / g.
If it exceeds, the stretchability tends to be poor. The heat of fusion of the composition occupying the whole film is 3.5 J / g to 19
J / g is preferable, and further 4 J / g to 14 J
/ G.

Here, the heat of fusion of the composition and the heat of fusion of the composition occupying the entire film may be determined from the peak which appears at the highest temperature when the composition and the film itself are measured by DSC, or the composition It may be calculated from the proportion of the polypropylene-based polymer (A) in the total. The multilayer film of the present invention has a heat-resistant layer (H
As a layer), a layer containing the above composition is contained.

In addition to the heat-resistant layer (H layer) made of a soft polyolefin resin composition composed of the polypropylene-based polymer (A) and the poly-1-butene-based polymer (B) described above, the preferable film structure is as follows. , A melting point temperature (Tpm) measured by DSC is 100 ° C. or less, and is a multilayer film containing both surface layers (S layer) made of a polyolefin resin.

Specific examples of the polyolefin resin having Tpm of 100 ° C. or less include ethylene-vinyl acetate copolymer (EVA), ethylene-ester monomers such as ethylene-ethyl acrylate and the like, aliphatic unsaturated monocarboxylic acid. , A copolymer with a monomer selected from the alkyl monocarboxylic acid ester, or at least a part of a polymer obtained by saponifying a part or more of the copolymer of the monomer and ethylene, for example, Na, Zn , A polymer ionically bonded with a metal ion such as Mg, an ethylene-α-olefin copolymer having a density of about 0.87 to 0.90 g / cm ³ , and the like.

Specific examples of the ethylene-α-olefin copolymer include α-ethylene and propylene, 1-butene, 1-pentene, 1-hexene, 4-methylpentene-1,1-octene, and the like. It may be a copolymer with an olefin, or a copolymer of this with a cyclopentadiene-based monomer, a norbornene-based monomer, or the like. Furthermore, the molecular weight distribution is narrow (Mw / Mn is 3.0 or less), and Tpm is 100.
It is more preferable that the film surface is not sticky even though it is as low as ℃ or less.

The film may have a three-layer structure of S / H / S, or may include S / M / H / S and S / M / containing other layers (M layers).
H / M / S, S / M / H / M / H / M / S, and further S /
M1 / H / M2 / S, S / M1 / H / M2 / H / M1 /
S (however, M1 ≠ M2) or the like may be used. Among the above, the S layer has a vinyl acetate content of 12 to 18 which is excellent in antifogging property and transparency.
A film using EVA of about wt% as an M layer and using an ethylene-α-olefin copolymer excellent in tensile strength and tear strength is preferable. Also, M layer, preferably S / M1
It can also be used as a resin (rework resin) obtained by collecting and re-pelletizing the film in the M2 layer of / H / M2 / H / M1 / S.

The thickness ratio of each layer is such that the S layer is 5 to 5 per layer.
45%, H layer is 10 to 90%, and M layer is 5 to 40%. In addition, the total thickness of the multilayer film is generally 5 to 25.
The thickness is about 7 μm, and is preferably 7 to 15 μm from the viewpoint of handleability and stretchability. An antifogging agent, an antistatic agent, an antibacterial agent, a defrosting agent, an ultraviolet absorber, an antioxidant and the like may be added to the above S layer, H layer and M layer, and further silicone oil or its oil may be added to the film surface. Emulsion, surfactant, powder,
A polymer or the like may be coated.

Preferred examples of the antifogging agent include saturated C1
2 fatty acids: C10 fatty acids: C8 fatty acids = 2: 4: 4 ~
Examples thereof include esters of mixed fatty acids of about 8: 1: 1 and diglycerin, and polyoxyethylene lauryl esters having HLB of 12 or more. In particular, it is more preferable to add the latter to the S layer and the former to the H layer or the M layer.
Examples of the method for obtaining the film of the present invention include a T-die cast method, a tenter biaxial stretching method (including simultaneous and sequential), a direct inflation method, a double bubble inflation method and the like. Of these, the double bubble inflation method is preferable.

The preferred double bubble inflation method will be described below. First, the resin composition of each layer is melt-extruded by a separate extruder, and combined and laminated by a multilayer circular die. This laminated body is rapidly cooled and solidified with a refrigerant to form a tube-shaped original sheet, which is folded and taken out. As a result, the degree of crystallinity of each resin layer is suppressed to a low level, and a highly transparent and highly glossy film can be obtained as compared with the direct inflation method. A surfactant, silicone oil (including emulsion), or the like may be filled in the tube-shaped raw material. Next, air is injected into the collected original fabric to form a tube again, and the polypropylene resin (A) having a melting point equal to or higher than that of the resin used for the S layer and having an H layer is used.
It is heated to a temperature equal to or lower than the melting point of, and stretched to an area ratio of 4 to 36 times. After stretching, it is folded and taken out, and if necessary, heat treatment, corona discharge treatment or the like is performed.

Here, the evaluation method of the present application will be described below. (1) Heat of fusion The heat of fusion was measured using DSC-7 manufactured by Perkin Elmer Co., Ltd., and the sample amount was 5 to 5 in accordance with JIS-K7122.
First, the temperature was raised from room temperature to 200 ° C. and held for 5 minutes, the temperature was cooled from 200 ° C. to −10 ° C. and held for 5 minutes, and then the temperature was raised to 200 ° C. again. It was determined from the peak area developed at the highest temperature. (2) Melting peak temperature (Tpm) The melting peak temperature (Tpm) is based on JIS-K7121, the sample amount is about 5 mg, and the temperature rising and cooling rate is 10 ° C./min. The temperature was held for 5 minutes, cooled from 200 ° C to -10 ° C, held for 5 minutes, and then again raised to 200 ° C. (3) Extrapolation melting start temperature (Tim) The extrapolation melting start temperature (Tim) is approximately 5 mg in accordance with JIS-K7121, and the temperature rising and cooling rates are 10 ° C /
As a minute, first, the temperature was raised from room temperature to 200 ° C. and held for 5 minutes, and after cooling from 200 ° C. to −10 ° C. and held for 5 minutes, it was determined from the peak that appeared at the highest temperature when the temperature was raised to 200 ° C. again. It was The peaks or shoulders within the range of 10 ° C. from the highest temperature peak were collectively regarded as one peak, and the peaks or shoulders on the lowest temperature side among the peaks or shoulders were extrapolated on the basis. The extrapolation melting start temperature (Tim) is shown as an Onset temperature in DSC-7 manufactured by Perkin Elmer. (4) Elongation load (g / cm width) A sample film was cut into a length of 100 mm and a width of 10 mm in each of the machine direction (MD) and the transverse direction (TD), and a tensile tester set to 50 mm between chucks was used. 23 ° C,
Pulling at a speed of 200 mm / min under the condition of 50% RH,
When the film is 100% deformed (100m between chucks
The load of m) was 100% elongation load, and the load when it was deformed by 200% was 200% elongation load. (5) Breaking stress (kg / cm ² ) A tensile test was performed under the same conditions as the above-mentioned measurement of elongation load, and the value obtained by dividing the stress at break by the film cross-sectional area before pulling was adopted. (6) Elongation at Break (%) A tensile test was performed under the same conditions as the above-mentioned measurement of elongation load, and the amount of deformation at break was divided by the original film length and expressed as a percentage. (7) Tear strength (g) Based on JIS-K7128, it measured in the machine direction and the cross direction of the film by the light load tear strength test. (8) Transparency / Evaluation Method Haze (%) was measured according to ASTM-D1003.・ Evaluation criteria Scale symbol Remark Haze ≦ 1.3 ◎ Excellent transparency 1.3 <Haze ≦ 2.0 ○ Practical no problem level 2.0 <Haze ≦ 3.0 Δ or less, practical problem Haze> 3.0 x Not suitable for practical use (9) Gloss / Evaluation method According to JIS-K7105, 60 degree specular gloss (GL
OSS,%) was measured. -Evaluation Criteria Scale Symbol Remarks GLOSS ≥ 130 ◎ Excellent gloss 120 ≤ GLOSS <130 ○ Practical level 110 ≤ GLOSS <120 △ Level of light loss GLOSS <110 × Not suitable for practical use (10 ) Heat-sealing property / evaluation method 200 g of clay was placed on a PP tray and wrapped with a film sample. In that case, a single film portion, a double overlapping portion, a three overlapping portion, and a five overlapping portion were formed on the bottom of the tray. 2 Make sure that the bottom of the tray comes into contact with the hot plate whose temperature is set in advance.
It was left for a second and immediately taken to observe the heat-sealed state of the films at the bottom of the tray. The temperature is set in steps of 5 ° C, and the lower limit temperature (T1:
Heat-sealable lower limit temperature) and upper-limit temperature (T2: heat-seal upper limit temperature) at which melt holes cannot be formed even in one sheet
The difference ΔT (° C) = T2-T1 was calculated.・ Evaluation criteria Scale symbol Remark △ T> 50 ◎ Excellent heat-sealing property 40 <△ T ≦ 50 ○ Practical level 30 <△ T ≦ 40 △ Available level under specific conditions △ T ≦ 30 x Not suitable for practical use (11) Impact resistance / evaluation method Using RDT-5000 / DART manufactured by Toyo Seiki Co., Ltd. with a constant temperature bath, the film breaking energy ENG (unit: J)
I asked. The type of dirt is SMALL ALUMINI
UM DART (3.75 kg) with a dart diameter of 5/8
Inch (15.88mmφ), maximum load of cell is 100
Pound (45.53 kgf), pedestal inner diameter 2.5 inches (63.5 mmφ), dirt drop speed 3.87 m
/ Sec (fall height is 76 cm). Measurement temperature is 15 ℃
And -Evaluation Criteria Scale Symbol Remarks ENG ≧ 0.5J ◎ Excellent impact resistance 0.2J ≦ ENG <0.5J ○ Above, pass level 0.1J ≦ ENG <0.2J △ ENG film tears by impact ENG <0. 1J × film is broken by impact (12) Wrapping property / evaluation method A sample film wound into a film width of 380 mm was evaluated for hand wrapping property and machine wrapping property. As the machine, Wmini-Zero1 manufactured by Ishida was used. The tray is a standard tray made by Chuo Kagaku SK-2.
0F, LY-18-25 made by FP Corporation as a large tray,
GS-30-10C manufactured by FP Corporation was used as a San Matray, and 300 g of clay was placed thereon, and 10 pieces each were packaged.

The standard tray (SK-20F) is relatively easy to wrap, but the large tray (LY-18-25) is a tray which is usually wrapped with a film having a film width of 400 mm or more, and has excellent stretchability. Otherwise, the tray is difficult to package. See also San Matrei (GS
-30-10C) is a vertically long tray in which packaging wrinkles easily remain.

The evaluation was carried out by observing whether or not the film was broken during packaging, whether the film could be packaged without wrinkles, and whether or not the film was broken.・ Evaluation Criteria Scale Symbol Remarks All 3 types of trays can be neatly packaged ◎ 2 types of trays with excellent packaging ability can be neatly packaged ○ Above, only 1 type of trays with passing level can be neatly packaged △ Conventional film There was no tray that could be packaged as clean as the above. × Not suitable for practical use (13) Anti-fog property / Evaluation method Put 200g slices of pork loin on PSP tray FS-B5 manufactured by Chuo Kagaku Co., and wrap with each film sample. So
The display was observed for 2 days in an open showcase at a temperature of around 5 ° C.・ Evaluation Criteria Scale Symbol Remarks Water film is uniform and contents look neat ◎ Optimal for practical use Water film looks uneven when viewed properly ○ Above, practical level Water drops appear to distort contents △ Practical Inappropriate film is clouded by water vapor and the inside cannot be seen × Not suitable for practical use (14) Comprehensive evaluation / evaluation method Transparency, glossiness, heat sealability, impact resistance, wrapping property,
A comprehensive evaluation was made for each item of antifogging property.・ Evaluation criteria Scale symbol Remarks All items are "◎" ◎ Most suitable for practical use All items are "◎" or "○" ○ Above, even one practical level is "×" or "△" item There is x Not suitable for practical use

[0044]

EXAMPLES First, the polymers used in this example are shown below. EVA1: ethylene-vinyl acetate copolymer [vinyl acetate content = 14% by weight, MI = 2.0 g / 10 minutes, melting point =
93 ° C.] EVA2: ethylene-vinyl acetate copolymer [vinyl acetate content = 15% by weight, MI = 7.0 g / 10 minutes, melting point =
90 ° C.) TPO1: propylene-ethylene block copolymer [heat of fusion = 34.3 J / g, Tpm = 164.7 ° C., T
im = 155.0 ° C., MFR = 0.8 g / 10 minutes (Montel-JPO, Adflex KS-081P)] TPO2: propylene-ethylene block copolymer [heat of fusion = 36.6 J / g, Tpm = 165.1 ° C, T
im = 152.9 ° C., MFR = 30 g / 10 minutes (Montel-JPO, Adflex KS-084P)] TPO3: propylene-ethylene block copolymer [heat of fusion = 61.9 J / g, Tpm = 139] 0.0 ° C, T
im = 117.4 ° C., MFR = 6.0 g / 10 min (Montel-JPO, Adflex C200F)] TPO4: propylene-ethylene block copolymer [heat of fusion = 23.7 J / g, Tpm = 154] 0.8 ° C, T
im = 142.9 [deg.] C., MFR = 1.5 g / 10 min (TOKUYAMA, P.E.R.R410E)]-TPO5: propylene-ethylene block copolymer [heat of fusion = 13.9 J / g, Tpm] = 153.0 ° C, T
im = 134.0 ° C., MFR = 1.5 g / 10 min (TOKUYAMA CORPORATION, PER T310J)] TPO6: propylene-ethylene block copolymer [heat of fusion = 84.7 J / g, Tpm] = 164.8 ° C, T
im = 158.7 ° C., MFR = 20 g / 10 min (Chisso Corporation, NEWCON / NK6120)] TPO7: propylene homopolymer consisting of isotactic polypropylene and atactic polypropylene [heat of fusion = 77.5 J / g, Tpm = 162.9 ° C., T
im = 147.3 ° C., MFR = 4.5 g / 10 min (Idemitsu Petrochemical Co., Ltd., Idemitsu TPO F3900)] TPO8: Propylene homopolymer consisting of isotactic polypropylene and atactic polypropylene [heat of fusion = 67 0.3 J / g, Tpm = 159.3 ° C., T
im = 140.3 ° C., MFR = 2.5 g / 10 min (Idemitsu Petrochemical Co., Ltd., Idemitsu TPO • E2700)] ・ TPO9: The above E2700 was reduced in molecular weight by adding a peroxide in an extruder [ Heat of fusion = 58.8 J / g, Tpm = 160.5 ° C., Tim = 1
41.6 ° C., MFR = 35 g / 10 minutes] TPO10: a low molecular weight by adding a peroxide to a propylene homopolymer (E2800, Idemitsu Petrochemical Co., Ltd.) consisting of isotactic polypropylene and atactic polypropylene in the extruder. The one that turned into.
[Heat of fusion = 61.6 J / g, Tpm = 160.4 ° C., T
im = 144.0 ° C., MFR = 75 g / 10 minutes] TPO11: 50% by weight of PP1 below and propylene.
1-butene copolymer [density = 0.87 g · cm ³ , melt viscosity (190 ° C.) = 8000 cps (Ube Lexen,
APAO / UT2780)] and 50 wt% thereof are melt-kneaded by a twin-screw extruder. -PP1: propylene homopolymer [heat of fusion = 102.5
J / g, Tpm = 163.1 ° C., Tim = 154.2
C, MFR = 4.0 g / 10 minutes (JPO, J-ALL
OMER-PL500A)]-PP2: propylene-ethylene-random copolymer [heat of fusion = 111.7 J / g, Tpm = 150.4 ° C,
Tim = 140.0 ° C., MFR = 1.0 g / 10 minutes (J
PO company, J-ALLOMER.EG110)]-PB1: 1-butene-propylene-random copolymer [Tpm = 72.5 ° C, Tim = 52.5 ° C, MI =
2.0 (Mitsui Chemicals, Tuffmer BL2281)] PB2: 1-butene ethylene random copolymer [Tpm = 97.9 ° C., Tim = 92.6 ° C., MI =
4.0 (Mitsui Chemicals Inc., TAFMER · BL3450)] · PE1: ethylene-1-octene random copolymer [density ^{= 0.868g · cm 3, Tpm =} 55.7 ℃,
MI = 0.5 (Dow Chemical Company, ENGAGE EG8
0.99)] - PE2: ethylene-1-octene random copolymer [density ^{= 0.902g · cm 3, Tpm =} 98.0 ℃,
MI = 3.3 (Dow Chemical Company, AFFINITY P
L1850)] · PE3: ethylene-1-octene random copolymer [density ^{= 0.875g · cm 3, Tpm =} 67.1 ℃,
MI = 3.0 (Dow Chemical Company, ENGAGE KC8
852)] TPS: hydrogenated product of styrene-isoprene-styrene triblock copolymer [styrene content = 20%, MFR
= 6g / 10 minutes (Kuraray Co., Ltd., High Blur HVS-
3)]

[0045]

Example 1 TPO1 of 60% by weight and PB1 as an H layer
Is used as an S layer for EVA1
1. A 1: 1 mixture of diglycerin oleate (Riken Vitamin Co., Rikemar O-71D) and monoglycerin oleate (Riken Vitamin Co., Rikemar OL100) was added to 2.
Each layer was mixed with S / H / S (=
(30% / 40% / 30%) was extruded from a circular die having a die lip diameter of 120 mm and a lip opening of 1.2 mm at a discharge rate of 22.5 kg / hr.
Air is injected while pulling this upward, pulling speed 17.8 m / min, blow-up ratio (BUR) =
Direct inflation molding was performed at 3.0 times to obtain a film having a thickness of 15 μm (Run. No. 1).

The obtained film was evaluated by the above method.

[0047]

[Comparative Example 1] In Example 1, only TPO1 in the H layer (Run. No. 2), PB1 in the H layer replaced with PE1 (Run. No. 3), and similarly replaced with TPS (Run). No. 4) was used, and the same experiment as in Example 1 was repeated. Further, only TPO11 was used for the H layer (Run. No. 5), TPO11: PB1 = 60: 4.
The same experiment as in Example 1 was repeated except that 0 (weight ratio) of the composition was used (Run. No. 6).

As described above, Run. No. 1-Run. No.
The results of No. 6 are summarized in Table 1. The following Table 1 is used for the first time according to the present invention to "polypropylene polymer (A)".
= "Block PP" is "heat resistant and flexible"
It will be explained that a "transparent" film can be obtained by utilizing the characteristics and forming a film. First, Example 1, Ru
n. No. The film No. 1 is a film using the composition of the present invention, and is excellent in heat sealing property and wrapping property by utilizing the characteristic of the block PP that is “heat resistant and flexible”, and has transparency (Haze). = 1.8%) and gloss (GLOSS = 130%).

On the other hand, Run. No. In the film No. 2, the heat-resistant layer (H layer) is a layer of block PP alone containing no poly-1-butene polymer (B), and has transparency (HAZE = 3.8%) and gloss (GLOSS =). 10
5%). Moreover, in place of the poly-1-butene polymer (B), an extremely low density ethylene / 1-octene copolymer (PE1) was used. No. The film of 3 also has transparency (HAZE = 5.2%) and gloss (GLOS).
S = 95%), and the optical characteristics were further inferior to the block PP alone.

Further, in place of the poly-1-butene polymer (B), a hydrogenated product of a block copolymer of styrene and a conjugated diene was used. No. The film of No. 4 had the same level of optical characteristics as the film of the present invention, but was inferior in impact resistance, and as a result, inferior in wrapping property. In addition, Run. N
o. 5 and Run. No. No. 6 is a film using a polypropylene homopolymer (PP1) and an amorphous and flexible resin APAO mechanically melt-blended (TPO11) instead of the block PP. N
o. 5 is a block PP independent use (Run. No. 2),
Run. No. Block 6 is a blend of block PP and poly-1-butene polymer (B) (Run. No. 1)
Corresponding to.

As is clear from a comparison between the two cases, it is clear that the block P in the simple polymer blend is
It can be seen that the characteristics like P cannot be exhibited.

[0052]

Example 2 In Example 1, TPO1 and PB of the H layer
The ratio with 1 was sequentially changed to 75% by weight / 25% by weight (R
un. No. 7) and the same 20 wt% / 80 wt% (Run. No. 8), except that the same experiment as in Example 1 was repeated.

[0053]

COMPARATIVE EXAMPLE 2 In Example 1, TPO1 and PB of the H layer
The ratio with 1 was sequentially changed to 80% by weight / 20% by weight (R
un. No. 9) and the same 15 wt% / 85 wt% (Run. No. 10) except that the same experiment as in Example 1 was repeated. As described above, Run. No. 7-Run. No. 1
The results of 0 are summarized in Table 2.

Hereinafter, polypropylene-based polymer (A) 10
3 parts by weight of poly-1-butene polymer (B) relative to 0 parts by weight.
The necessity of 0 to 400 parts by weight will be described. Ru
n. No. 7 and Run. No. The film of No. 8 was a film using the composition of the present invention in the H layer, and was at or above the passing level in all items. On the other hand, Run.
No. The film of No. 9 is a poly-1-butene polymer (B) based on 100 parts by weight of the polypropylene polymer (A).
Is as small as 25 parts by weight, and therefore transparency (HAZE = 3.
0%), gloss (GLOSS = 110%) and other optical properties are inferior, and the above poly-1-butene polymer (B) is used.
It can be seen that the effect of blending is not exhibited.

Run. No. The film of No. 10 was made of poly
1-Butene polymer (B) is in excess of 566 parts by weight, and heat resistance (heat-seal upper limit temperature T2 = 130 ° C.) and flexibility (impact resistance) which are characteristics of polypropylene polymer (A) are utilized. I know there isn't. From the above, poly.
It can be seen that the 1-butene polymer (B) needs to be 30 to 400 parts by weight.

[0056]

Third Embodiment In the first embodiment, the TPO1 of the H layer is replaced with TP.
Replaced with O4 (Run. No. 11), similarly TPO7
(Run. No. 12), but the same experiment as in Example 1 was repeated.

[0057]

Comparative Example 3 In Example 1, the TPO1 of the H layer is replaced with TP.
Replaced with O5 (Run. No. 13), similarly TPO6
(Run. No. 14), similarly to TPO3 (Run. No. 15), and similarly to PP2 (Run. No. 16), the same experiment as in Example 1 was repeated. .

As described above, Run. No. 11-Run. N
o. The results of 16 are summarized in Table 3. The polypropylene-based polymer (A) has a heat of fusion of 15 to 80 J / g and a melting peak temperature (Tpm) of 15 as measured by DSC.
The necessity of being 0 ° C. or higher will be described.

Run. No. 11 and Run. No. 1
2 is a film using the composition of the present invention in the H layer, and was excellent in all evaluations. Especially Tpm-Tim is 15.6.
Run. Using TPO7 at 0 ° C. No. 12 is HAZ
E. = 1.5% and Run. No. It was most excellent in transparency among 1 to 16.

On the other hand, Run. No. In the film of No. 13, the heat of fusion of the polypropylene polymer of the H layer is 13.
9 J / g (The heat of fusion for the whole film is 3.3 J / g
heat resistance (T2) and heat resistance (T2)
= 130 ° C). In addition, Run. No. In the film No. 14, the heat of fusion of the polypropylene polymer in the H layer is as large as 84.7 J / g, and therefore, the resin itself is poor in flexibility because the soft component in the resin is small, and as a result, the elongation at break is small. The film was inferior in wrapping property.

Furthermore, Run. No. 15 films are
H-layer polypropylene polymer has a heat of fusion of 61.9 J /
Although it has a large g, Tpm is as low as 139 ° C., so the heat resistance is also inferior, and the film has heat sealability (T2
= 130 ° C). Run. No. 16 is a film using propylene-ethylene / random copolymer (PP2) as a polypropylene polymer for the H layer, having a Tpm of 150 ° C. or higher and a heat of fusion of 111.7J.
The heat sealability is not as good as that of the film using the resin of the present invention, and the transparency (HAZE = 2.2%) and the gloss are obtained even though the copolymer having relatively high heat resistance is used. The optical characteristics (GLOSS = 120%) were also inferior to those of the film using the resin of the present invention.

Since the heat of fusion was as high as 111.7 J / g, the flexibility was insufficient and the packaging property was poor. If the ethylene content is reduced to increase Tpm and the heat of fusion is increased in order to improve the heat sealability, Run. No. It becomes a film with inferior optical characteristics like the film of No. 6, and conversely, if the ethylene content is increased to improve the optical characteristics and flexibility, only a film with inferior heat resistance can be obtained, and both are satisfied. It is clear from this experiment that there is no region that can be created.

From the above, the heat of fusion of the polypropylene polymer (A) measured by DSC is 15 to 80 J / g.
It can be seen that the melting peak temperature (Tpm) needs to be 150 ° C. or higher.

[0064]

[Example 4] As the S layer, 1.0 wt% of polyoxyethylene lauryl ester having an HLB of about 13 was kneaded in EVA2 as the S layer, and PE2 was saturated with C12 fatty acid: C10 fatty acid: C8 fatty acid = 6 as the M layer. : 2.0% by weight of an ester (HLB = about 6.5) of a mixed fatty acid of 2: 2 and diglycerin (HLB = about 6.5) was kneaded, and TPO2 was 6 as an H layer.
0% by weight and 40% by weight of PB2 (Run.N.
o. 17) is melt-kneaded with three extruders, and the die lip diameter is 200 mm and the lip opening is 1.1 m.
S / M / H / M / S (=
(10% / 25% / 30% / 25% / 10%), and the mixture is extruded at a discharge rate of 15.0 kg / hr, and water having a temperature of 20 ° C. is discharged from an annular lip to quench the laminate. It was solidified into a tube-shaped original fabric, which was folded and taken out. At this time, a 10% aqueous solution of polyoxyethylene lauryl ester having an HLB of about 13 used for the S layer was enclosed in the tube.

Bubbles were formed in the tube-shaped original fabric (thickness: about 140 μm) by injecting air again and rotating it with a twister to further blow air through a heating furnace having an ambient temperature of about 120 ° C. The stretching ratio was 4.2 times in the machine direction (MD) and 3.1 times in the transverse direction (TD), and the film thickness was 11 μm. The resulting film was evaluated by the above method.

Similarly, the composition of the H layer was changed to TPO2: P.
B2 = 40: 60 (weight ratio) replaced (Run.N
o. 18), the composition of the H layer was TPO8: PB2 = 40:
Replaced with 60 (weight ratio) (Run. No. 19),
Replacing the composition of the H layer with TPO9: PB2 = 40: 60 (weight ratio) (Run. No. 20), TP of the H layer
O10: PB2 = 40: 60 (weight ratio) was replaced (Run. No. 21), and the layer structure was S / M / H.
The same experiment was repeated except that / M / S = 10% / 20% / 40% / 20% / 10%.

Run. No. 17-Run. No.
The results of No. 21 are summarized in Table 4. Run. No. 17
The film of Run. No. Compared with film No. 1, transparency (Haze = 1.2%), gloss (GLOSS = 13)
5%) and other optical characteristics were further excellent. In addition, Run. N
o. The film of No. 1 had to be pulled strongly in order to remove the wrinkles of the film when carrying out the hand wrapping. No. The film of No. 17 is Run. No. 1
The wrinkles on the film could be removed more easily than on the other film.
Moreover, the balance between MD and TD of tear strength of the film was excellent, the cutting property by the cutting blade in the packaging machine was excellent, and the generation of scraps was small. Furthermore, the antifogging property was also excellent.

Run. No. 19 and Run. No. 20
In comparison with Run. No. 20 is Run. N
o. The polypropylene-based polymer (A) having a larger MFR than 19 was used, and the MD elongation at break and tear strength of the film were large, and the film was excellent in wrapping property.
Run. No. 18 and Run. No. In comparison with Run. No. The polypropylene-based polymer (TPO2) of 18 had Tpm-Tim = 12.2 ° C.,
See also Run. No. That of 21 is 16.4 ° C.

When the Tpm-Tim is a value larger than 16.4 ° C., Run. No. The 21st film is Haze
= 0.8%, GLOSS = 142%, and Run. No.
Haze of 18 films = 1.8%, GLOS = 1
Compared to 30%, both transparency and gloss were remarkably excellent. In addition, the Tpm-Tim of Run. No. 19
Haze = 0.7% and GLOSS for films 20 and 20
= 147%, both transparency and gloss were excellent.

[0070]

Example 5 Example 4, Run. No. At 20,
The resin for the S layer was replaced with PE3 (Run. No. 22), and similarly, the resin for the S layer was replaced with PE2 (Run. No. 2).
3) Others are described in Example 4, Run. No. An experiment similar to 20 was repeated.

As described above, Run. No. 20, 22, and 23
The results are summarized in Table 5. Hereinafter, it will be described that both surface layers (S layer) of the film of the present invention are preferably made of a polyolefin resin having Tpm of 100 ° C. or less. The Tpm of the resin of the S layer is Run. No. 22 is about 67 ° C. and Run. No. 20 ° C or more lower than 90 ° C of 20 and therefore has heat sealability (heat seal lower limit temperature =
(75 ° C) has improved significantly.

On the other hand, Run. No. The film of No. 23 had a high Tpm of the resin for the S layer of about 98 ° C., and the heat sealability was slightly lowered. In addition, the S layer is made of an ethylene-α / olefin copolymer of Run. No. 22 is the Run. No. Tear strength was larger than that of No. 20 and was preferable, but it was inferior in antifogging property. In addition, the transparency was inferior to some extent (Haze: Run. No. 20 = 0.7).
%, Run. No. 22 = 0.9%).

[0073]

Example 6 Example 4, Run. No. At 21,
40% by weight of HPO layer, 22% by weight of PB2,
EVA2 is 13% by weight and PE2 is 25% by weight, and the layer thickness ratio is S / M / H / M / S = 10%.
The same experiment was repeated except that it was set to / 20% / 40% / 20% / 10% (Run. No. 24).

Next, in Example 4, Run. No. 21, the M layer is a composition comprising 70% by weight of PE2, 15% by weight of EVA, 6% by weight of TPO10 and 9% by weight of PB2, and the layer thickness ratio is S / M / H / M / S = 10
% / 30% / 20% / 30% / 10%, but in Example 4, Run. No. The same experiment as in No. 21 was repeated (Run. No. 25).

As described above, Run. No. 21, 24 and 25
The results are collectively shown in Table 6. In this experiment, a method for collecting and reusing a film (rework) was examined. Run. No. 21 is a case where rework is not performed at all, and Run. No. 24 is the H layer, Ru
n. No. 25 is the case where reworking was performed on the M layer.
For rework, about 20% by weight of the entire film was collected and reused (rework rate = 20%).

Run. No. 24, Run. No. Two
Although the transparency (HAZE = 0.9%) and the glossiness (GLOSS = 140%) were slightly inferior to those of No. 1, almost the same evaluation results were obtained. Run. No. 25, Run.
No. It was a film having excellent characteristics similar to 24.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

[Table 3]

[0080]

[Table 4]

[0081]

[Table 5]

[0082]

[Table 6]

[0083]

According to the present invention, the high impact of the conventional level,
For the first time, it is possible to provide a soft polyolefin resin composition having excellent heat resistance that can impart stretchability while maintaining high heat-sealing properties and high display properties (specifically, transparency, glossiness, and antifogging properties). By using the composition, it is possible to provide a film which is much more convenient to use than conventional films.

Needless to say, the composition of the present invention is useful not only for stretch packaging but also for shrink packaging and other applications requiring heat resistance and flexibility.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29K 23:00 B29L 9:00

Claims (3)

[Claims] 1. The heat of fusion measured by a differential scanning calorimeter (DSC) is 15 to 80 J / g, and the melting peak temperature (Tp
m) 100 parts by weight of a polypropylene-based polymer (A) having a temperature of 150 ° C. or higher and a poly / 1-butene-based polymer (B)
A soft polyolefin resin composition comprising 30 to 400 parts by weight. 2. The heat resistant layer (H layer) has a heat of fusion of 15 to 80 J / g measured by a differential scanning calorimeter (DSC),
Contains a soft polyolefin resin composition layer consisting of 100 parts by weight of a polypropylene-based polymer (A) having a melting peak temperature (Tpm) of 150 ° C. or higher and 30 to 400 parts by weight of a poly-1-butene-based polymer (B) Multi-layer film to do. 3. Both surface layers (S layer) containing, in addition to the heat resistant layer (H layer), a polyolefin resin having a melting peak temperature (Tpm) measured by a differential scanning calorimeter (DSC) of 100 ° C. or less. The multilayer film according to claim 2, which comprises: