JP5487025B2 - Propylene-based resin multilayer sheet and package for heat treatment using the same - Google Patents

Description

  The present invention relates to a multilayer sheet and a package for heat treatment using the multilayer sheet, and more specifically, even when heat treatment under pressure such as pressurized steam treatment or pressurized hot water treatment is performed, deformation, inner surface fusion, etc. The present invention relates to a propylene-based resin multilayer sheet having good transparency, flexibility and impact resistance while having excellent heat resistance, and a heat treatment packaging body using the same.

Performance required for packaging bags that need to be sterilized and sterilized by applying pressure treatment such as retort packaging and infusion bags for chemicals, etc. Transparency to confirm contents, drainage without opening air holes Flexibility to enable, low temperature storage to maintain the quality of contents, low temperature impact resistance not to break the bag during low temperature transportation, 121 ° C sterilization, heat resistance to prevent deformation and fusing even during sterilization processing, Examples include suitability for secondary processing such as heat sealing characteristics for easy bag-making.
Especially for infusion bags, vinyl chloride resin was once used as a material that satisfies the above-mentioned performance. However, there are problems such as elution of plasticizers and difficulty in disposal, and consideration for the global environment in recent years. Therefore, it has been replaced by polyolefin resin.

  The infusion bag mainly composed of polyethylene is excellent in flexibility and impact resistance but has poor heat resistance. At the sterilization temperature of 121 ° C., which is an overkill condition, appearance defects such as deformation occur and satisfy the performance as an infusion bag. It cannot be done (for example, Patent Document 1). On the other hand, an infusion bag mainly composed of polypropylene has good heat resistance, but it is hard as an infusion bag material and lacks impact resistance at low temperatures. (For example, Patent Document 2).

  Then, the technique which added the elastomer component to the polypropylene and provided the softness | flexibility and impact resistance is disclosed (for example, patent document 3). However, there is a problem that the heat resistance of polypropylene is sacrificed, and low molecular weight components after sterilization are bleed out and transparency is deteriorated. Although there is also a disclosure of a technique of adding a styrene elastomer as an elastomer component (for example, Patent Document 4), blocking tends to occur and it is difficult to say that the productivity is excellent. Styrenic elastomers are more expensive than olefinic elastomers, and there remains a problem with cost.

Separately, a polypropylene block copolymer has been developed in which an elastomer component is added by continuous polymerization using a Ziegler-Natta catalyst (for example, Patent Document 5). Is not good. On the other hand, a water-cooled inflation film composed of a propylene-ethylene block copolymer in which an elastomer component is added by continuous polymerization using a metallocene catalyst has been proposed, and bleedout improvement under 40 ° C. conditions has been seen ( For example, Patent Document 6) is still insufficient in impact resistance at low temperatures. Moreover, although the medical film containing a heterogeneous blend is proposed (for example, patent document 7), the impact resistance in low temperature was inadequate.
In other words, there is a need for a low-cost infusion bag material that has a sufficient balance of heat resistance, transparency, flexibility, and impact resistance, but the current situation is that no satisfactory material has been found. .

  In addition, the infusion bag bag forming process includes a process of fusing with spouts, injection parts such as a discharge port and an injection port, and it is necessary to melt the film for sufficient fusing. For this reason, extremely severe (high temperature, high pressure, long time, etc.) heat sealing is performed. In a sufficiently molten state, the molten resin sticks to the seal bar, and the productivity cannot be denied. Thus, a technique is disclosed in which the inner layer is melted while the outer layer remains solid by providing a melting point difference between the outer layer and the inner layer by lamination (for example, Document 7). However, since the inner layer is a polyethylene-based resin, it can withstand a sterilization temperature of 115 ° C., but sterilization at 121 ° C. causes the inner surfaces of the films to be fused together, and the heat resistance is not sufficient.

JP-A-9-308682 JP-A-9-99036 JP-A-9-75444 JP-A-9-324022 JP 2006-307072 Special table 2008-524391 JP2007-245490

To have a balance of transparency, heat resistance, and flexibility, which are the performance required for packaging bags for heat treatment, and a propylene-α-olefin random copolymer that exhibits heat resistance and flexibility without losing transparency It is effective to use a combination of propylene-ethylene random copolymer to which a specific amount of ethylene obtained by a metallocene-based catalyst that can be converted is added. In addition, polyolefins obtained using metallocene-based catalysts have very low low molecular weight components and low regularity components, so they are excellent in cleanliness and suitable for the food and medical fields. Impact resistance may be insufficient.
Therefore, the present invention provides a multilayer sheet that is excellent in flexibility, transparency, impact resistance, heat resistance, cleanliness, and can withstand severe heat seal conditions during bag making, and a packaging for heat treatment using the same. Is to provide.

  In order to solve the above problems, the present inventors conducted various studies and analyzes, arranged a propylene-based resin having a specific melting peak temperature in the outer layer, and propylene having a specific melting peak temperature in the inner layer. -Mixing a specific amount of a mixture of an α-olefin copolymer and a propylene-ethylene random copolymer having a specific ethylene content and an ethylene-α-olefin copolymer having a specific density and melt flow rate; It has been found that the above problems can be solved in a well-balanced manner by using a propylene-based resin composition containing a specific propylene-based resin composition and a specific ethylene-α-olefin copolymer as the layer. With the above resin composition and layer structure, the inventors have obtained the knowledge that the performance required for the heat treatment packaging body can be obtained in a well-balanced and high level, and the present invention has been achieved.

That is, according to the first invention of the present invention, there is provided a propylene-based resin multilayer sheet, which is a multilayer sheet composed of at least three layers in the order of an outer layer, an intermediate layer, and an inner layer, and each layer satisfies the following conditions: Provided.
(1) Intermediate layer The propylene resin composition (X) constituting the intermediate layer satisfies the following conditions (Ai) to (A-iii): 60 to 90 wt% of the propylene resin composition (A) , and An ethylene-α-olefin copolymer (B) satisfying the following conditions (Bi) to (B-ii) is contained in an amount of 40 to 10 wt%.
Propylene resin composition (A):
(Ai) 30 to 70 wt% of a propylene-α-olefin random copolymer (A1) having a melting peak temperature (Tm (A1)) of 125 to 145 ° C., an ethylene content obtained using a metallocene catalyst ( E [A2]) is obtained by mixing 70 to 30 wt% of a propylene-ethylene random copolymer (A2) having 7 to 17 wt% by a method other than the polymerization blend method.
(A-ii) Melt flow rate (MFR (A): 230 ° C., 2.16 kg) is in the range of 0.5 to 20 g / 10 min.
(A-iii) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the peak of the tan δ curve representing the glass transition observed in the range of −60 to 20 ° C. is less than 0 ° C. One peak is shown.
-Ethylene-α-olefin copolymer (B):
(Bi) The density is in the range of 0.860 to 0.910 g / cm ³ .
(B-ii) The melt flow rate (MFR (B): 190 ° C., 2.16 kg) is in the range of 0.1 to 20 g / 10 minutes.
(2) Outer layer The propylene-based resin composition (Y) constituting the outer layer contains a propylene-based resin (D) having a melting peak temperature Tm (D) in the range of 135 to 170 ° C.
(3) Inner layer The propylene-based resin composition (Z) constituting the inner layer is a propylene-based resin composition (G) that satisfies the following conditions (G-i) to (G-ii) (45) to 89 wt%, and the following condition (H The ethylene-α-olefin copolymer (H) satisfying -i) is contained in an amount of 10 to 30 wt%, and the propylene resin (I) satisfying the following condition (Ii) is contained in an amount of 1 to 25 wt%.
Propylene resin composition (G):
(Gi) Using a metallocene-based catalyst, 50 to 60 wt% of a propylene-α-olefin random copolymer component (G1) having a melting peak temperature Tm (G1) of 125 to 135 ° C. in DSC measurement in the first step. The propylene-ethylene block copolymer obtained by sequentially polymerizing 50-40 wt% of the propylene-ethylene random copolymer component (G2) having an ethylene content (E [G2]) of 8-14 wt% in the second step It is a coalescence.
(G-ii) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the peak of the tan δ curve representing the glass transition observed in the range of −60 to 20 ° C. is simply below 0 ° C. One peak is shown.
-Ethylene-α-olefin copolymer (H):
(Hi) The density is in the range of 0.860 to 0.910 g / cm ³ .
Propylene resin (I):
(Ii) The melting peak temperature Tm (I) is higher by 6 ° C. or more than the melting peak temperature Tm (G1).

  According to the second invention of the present invention, in the first invention, the propylene-α-olefin random copolymer component (A1) in the propylene-based resin composition (A) uses a metallocene catalyst. A propylene-based resin multilayer sheet characterized by being obtained is provided.

According to the third invention of the present invention, in the first or second invention, the propylene-based resin composition (X) constituting the intermediate layer further contains the following conditions (Ci) to (C-ii) Propylene-based resin (C) satisfying the composition, and the composition of the resin composition (X) is 45-89 wt% of the propylene-based resin composition (A), 10-30 wt% of the ethylene-α-olefin copolymer (B). And a propylene-based resin multilayer sheet characterized by being 1 to 25 wt% of the propylene-based resin (C).
Propylene resin (C):
(Ci) The melting peak temperature (Tm (C)) is 6 ° C. or more higher than the melting peak temperature (Tm (A1)) of the propylene-α-olefin random copolymer (A1).
(C-ii) The melt flow rate (MFR (C): 230 ° C., 2.16 kg) is in the range of 0.5 to 30 g / 10 minutes.

  Moreover, according to the 4th invention of this invention, the package for heat processing which uses the propylene-type resin multilayer sheet of any one of the 1st-3rd invention is provided.

  Furthermore, according to the fifth invention, in the fourth invention, there is provided a heat treatment package characterized in that the heat treatment package is an infusion bag.

  The basic requirements for the multilayer sheet of the present invention and the heat treatment packaging body using the multilayer sheet are as follows: a specific propylene resin composition (A) and a specific ethylene-α-olefin copolymer ( The propylene resin composition (X) containing B) is used, the outer layer (2) is a propylene resin composition (Y) using a specific propylene resin (D) as a main material, and the inner layer ( 3) is to use a propylene-ethylene block copolymer (G), a specific ethylene-α-olefin copolymer (H) and a specific propylene-based resin (I) obtained by sequential polymerization.

  The propylene-based resin composition (A) used for the propylene-based resin composition (X) constituting the intermediate layer (1) includes a propylene-α-olefin random copolymer (A1) having a melting peak temperature in a specific range and The propylene-ethylene random copolymer component (A2) obtained using a metallocene catalyst and having a specific ethylene content is obtained by mixing by a method other than the polymerization blend method, and has high flexibility, Since the glass transition temperature observed as the peak of the tan δ curve in the range of −60 to 20 ° C. in the solid viscoelasticity measurement is a propylene-based resin composition (A) showing a single peak at 0 ° C. or less, the resulting multilayer Transparency and flexibility can be imparted to the sheet in a balanced manner.

The ethylene-α-olefin copolymer (B) to be blended in the intermediate layer (1) is specified by density and melt flow rate, and the obtained multilayer sheet has flexibility without impairing transparency. Can be granted.
In a preferred embodiment, the intermediate layer (1) is further blended with a propylene resin (C). The propylene resin (C) used in this case is specified by the melting peak temperature and the melt flow rate. Yes, by making the melting point peak temperature 6 ° C. or more higher than that of the propylene-based resin composition (A), the resulting multilayer sheet does not cause appearance defects such as bleed out, and has poor appearance such as thickness fluctuation and interface roughness. The function which suppresses the thinning at the time of heat sealing can be provided.

  The propylene-based resin composition (Y) used for the outer layer (2) uses the propylene-based resin (D) specified by the melting peak temperature, and the multilayer sheet adheres to the seal bar during heat sealing. It is possible to prevent and impart bag making aptitude.

  The multilayer sheet of the present invention is a multilayer sheet comprising at least three layers having an inner layer (3) in the order of an outer layer (2), an intermediate layer (1), and an inner layer (3). The propylene-based resin composition (Z) used is composed mainly of the propylene-based resin composition (G), and the propylene-based resin composition (G) is a propylene-α-olefin random copolymer that exhibits a melting peak temperature in a specific range. Sequentially polymerizing the polymer component (G1) and the propylene-α-ethylene copolymer component (G2) obtained by using a metallocene catalyst and having a specific ethylene content that is highly flexible and does not deteriorate transparency Is obtained. By using this, transparency and flexibility can be imparted in a balanced manner to the resulting multilayer sheet.

The ethylene-α-olefin copolymer (H) used in the propylene-based resin composition (Z) is specified by density, and gives flexibility to the obtained multilayer sheet without impairing transparency. Can be made.
Furthermore, the propylene-based resin (I) used in the propylene-based resin composition (Z) is specified by the melting peak temperature, and the inner layer (3) is thermally fused to the resulting multilayer sheet during heat treatment. The heat resistance which prevents it can be given.

  Therefore, the propylene-based resin multilayer sheet of the present invention and the heat treatment package using the multilayer sheet are excellent in transparency, flexibility, impact resistance, cleanliness, etc. Since the deterioration of appearance such as roughening of the interface is suppressed and the thinning at the time of secondary processing is improved, it can be used particularly suitably for retort packaging and infusion bag applications.

The propylene-based resin multilayer sheet of the present invention uses the propylene-based resin composition (X) for the intermediate layer (1), the propylene-based resin composition (Y) for the outer layer (2), and further converts the inner layer (3) to the outer layer (3). 1), a multilayer sheet comprising at least three layers in the order of the intermediate layer (1) and the inner layer (3), and a heat treatment package obtained therefrom.
Hereinafter, each layer constituent of the propylene-based resin multilayer sheet of the present invention, production of each layer constituent, and a heat treatment package will be described in detail.

[I] Components constituting each layer of the propylene-based resin multilayer sheet Middle layer (1)
The intermediate layer (1) is formed from the following propylene resin composition (A) and a propylene resin composition (X) containing an ethylene-α-olefin copolymer (B). The propylene resin composition (X) preferably further contains a propylene resin (C).

(1) Propylene resin composition (A)
(1-1) Properties of Propylene Resin Composition (A) Propylene Resin Composition Used as a Component of Propylene Resin Composition (X) of Intermediate Layer (1) of the Propylene Resin Multilayer Sheet of the Present Invention ( A) (hereinafter sometimes referred to as component (A)) needs to have high transparency, flexibility and impact resistance. In order to satisfy these requirements at a high level, the component (A) needs to satisfy the following conditions (A-i) to (A-iii).

-Basic rules of propylene-based resin composition (A) Component (A) used in the present invention is a propylene-based resin composition (A) that satisfies the following conditions (Ai) to (A-iii).
(Ai) 30 to 70 wt% of a propylene-α-olefin random copolymer (A1) having a melting peak temperature (Tm (A1)) of 125 to 145 ° C., an ethylene content obtained using a metallocene catalyst (E [A2]) is obtained by mixing 70 to 30 wt% of propylene-ethylene random copolymer (A2) having 7 to 17 wt% by a method other than the polymerization blend method.
(A-ii) Melt flow rate (MFR (A): 230 ° C., 2.16 kg) is in the range of 0.5 to 20 g / 10 min.
(A-iii) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the peak of the tan δ curve representing the glass transition observed in the range of −60 to 20 ° C. is less than 0 ° C. One peak is shown.
The above conditions will be described in detail in the following (i) to (iv).

(Ai) Melting peak temperature of propylene-α-olefin random copolymer (A1) (Tm (A1))
A copolymer (A1) is a component which determines crystallinity in a propylene-type resin composition (A). In order to improve the heat resistance of the propylene-based resin composition (A), it is necessary that the copolymer (A1) has a high melting peak temperature Tm (A1) (hereinafter sometimes referred to as Tm (A1)). On the other hand, if Tm (A1) is too high, flexibility and transparency are hindered. Moreover, when Tm (A1) is too low, heat resistance will deteriorate and thinning will advance at the time of heat sealing. Tm (A1) needs to be in the range of 125 to 145 ° C, preferably 125 to 138 ° C, more preferably 128 to 135 ° C. The copolymer (A1) is preferably produced using a metallocene catalyst.

  Here, the melting peak temperature Tm is a value obtained by a differential scanning calorimeter (DSC manufactured by Seiko Co., Ltd.). Specifically, a sample amount of 5.0 mg is taken and held at 200 ° C. for 5 minutes, and then 40 ° C. It is a value obtained as a melting peak temperature when crystallization is performed at a temperature lowering speed of 10 ° C./min until further melting at a temperature rising speed of 10 ° C./min.

(Ii) Proportion of copolymer (A1) in propylene resin composition (A) Proportion W (A1) of copolymer (A1) in propylene resin composition (A) is propylene resin Although it is a component that imparts heat resistance to the composition (A), if there is too much W (A1), flexibility, impact resistance, and transparency cannot be sufficiently exhibited. Therefore, the proportion of the copolymer (A1) needs to be 70 wt% or less.
On the other hand, if the proportion of the copolymer (A1) is too small, the heat resistance is lowered even if the Tm (A1) is sufficient, and the copolymer (A1) may be deformed in the sterilization and sterilization processes. The proportion of A1) must be 30 wt% or more. A preferable range of W (A1) is 50 to 60 wt%.

(Iii) Ethylene content E [A2] in the propylene-ethylene random copolymer (A2)
The propylene-ethylene random copolymer (A2) is a component necessary for improving the flexibility, impact resistance, and transparency of the propylene-based resin composition (A), and is obtained using a metallocene-based catalyst. In general, in the propylene-ethylene random copolymer, the crystallinity is lowered and the flexibility improving effect is increased by increasing the ethylene content. Therefore, the ethylene content E [A2] (hereinafter referred to as the copolymer (A2)) is increased. , E [A2]) is required to be 7 wt% or more. When E [A2] is less than 7 wt%, sufficient flexibility cannot be exhibited, and it is preferably 8 wt% or more, more preferably 10 wt% or more.
On the other hand, if E [A2] is increased too much in order to lower the crystallinity of the copolymer (A2), the compatibility of the copolymer (A1) and the copolymer (A2) decreases, and the copolymer (A2 ) Form a domain without being compatible with the copolymer (A1). In such a phase separation structure, if the refractive index of the matrix and the domain are different, the transparency is drastically lowered. Therefore, E [A2] of the copolymer (A2) in the propylene-based resin composition (A) used in the present invention needs to be 17 wt% or less, preferably 14 wt% or less, more preferably 12 wt%. It is as follows.

(Iv) Proportion of propylene-ethylene random copolymer (A2) in the propylene-based resin composition (A) Proportion of propylene-ethylene random copolymer (A2) in the propylene-based resin composition (A) W When (A2) is too much, heat resistance is lowered, so W (A2) needs to be suppressed to 70 wt% or less.
On the other hand, if W (A2) becomes too small, the effect of improving the flexibility and impact resistance cannot be obtained, so W (A2) needs to be 30 wt% or more. A preferable range of W (A2) is 50 to 40 wt%.

(1-2) Method for Producing Propylene Resin Composition (A) The propylene resin composition (A) used in the present invention is a separately produced propylene-α-olefin random copolymer (A1) and propylene. -The ethylene random copolymer (A2) is produced by using a mixing apparatus without using the polymerization blending method. And the like, and the like.

(A-ii) Melt flow rate MFR of propylene-based resin composition (A) (A)
The melt flow rate MFR (230 ° C., 2.16 kg) (hereinafter sometimes referred to as MFR (A)) of the propylene-based resin composition (A) used in the present invention is 0.5 to 20 g / 10 min. It is necessary to take a range.
MFR (A) is also referred to as MFR corresponding to propylene-α-olefin random copolymer (A1) and propylene-ethylene random copolymer (A2) (hereinafter referred to as MFR (A1) and MFR (A2)). In the present invention, if MFR (A) is in the range of 0.5 to 20 g / 10 min, MFR (A1) and MFR (A2) are the objects of the present invention. It is optional as long as it does not impair. However, when the MFR difference between the two is greatly different, there is a risk of appearance failure or the like. Therefore, both MFR (A1) and MFR (A2) are preferably in the range of 4 to 10 g / 10 minutes.
If the MFR (A) is too low, the resistance to rotation of the molding machine screw increases, so that not only the motor load and the tip pressure increase, but also the problem arises that the appearance of the sheet deteriorates due to the rough surface of the sheet. Therefore, MFR (A) is preferably 4 g / 10 minutes or more, more preferably 5 g / 10 minutes or more.
On the other hand, if the MFR (A) is too high, the molding tends to become unstable and it becomes difficult to obtain a uniform sheet. Therefore, the MFR is preferably 10 g / 10 min or less, preferably 8 g / 10 min or less. is there.
Here, MFR is a value measured according to JIS K7210.

(A-iii) Temperature-loss tangent (tan δ) curve peak The propylene-based resin composition (A) used in the present invention is a temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA). It is necessary that the peak of the tan δ curve representing the glass transition observed in the range of 60 to 20 ° C. shows a single peak at 0 ° C. or lower.
When the propylene resin composition (A) has a phase separation structure, the glass transition temperature of the amorphous part contained in the propylene-α-olefin random copolymer (A1) and the propylene-ethylene random copolymer (A2) ) Have a plurality of peaks because the glass transition temperatures of the amorphous parts included in each are different. In this case, there arises a problem that the transparency is remarkably deteriorated.
Usually, the glass transition temperature in the propylene-ethylene random copolymer (A2) is observed in a range of −60 ° C. to 20 ° C., and whether or not a phase separation structure is taken is obtained by solid viscoelasticity measurement in this range. Avoidance of the phase separation structure that can be distinguished in the tan δ curve and affects the transparency of the sheet is brought about by having a single peak below 0 ° C.

  Here, the solid viscoelasticity measurement (DMA) is specifically performed by applying a sine distortion of a specific frequency to a strip-shaped sample piece and detecting the generated stress. The frequency is 1 Hz, and the measurement temperature is raised stepwise from −60 ° C. until the sample is melted and cannot be measured. Further, it is recommended that the magnitude of distortion is about 0.1 to 0.5%. From the obtained stress, the storage elastic modulus G ′ and the loss elastic modulus G ″ are obtained by a known method, and the loss tangent (= loss elastic modulus / storage elastic modulus) defined by this ratio is plotted against the temperature. In the temperature range of 0 ° C. or lower, a sharp peak is generally observed, and the peak of the tan δ curve at 0 ° C. or lower observes the glass transition of the amorphous part, and in the present invention, this peak temperature is expressed as the glass transition temperature Tg ( ° C).

(1-2) Proportion of propylene-based resin composition (A) in intermediate layer (1) The proportion of propylene-based resin composition (A) in the intermediate layer configuration is that of propylene-based resin composition (A) and ethylene-α. -It is necessary to be in the range of 60 to 90 wt%, preferably 65 to 85 wt% with respect to 100 wt% of the total amount of the olefin copolymer (B).
If the content of the propylene resin composition (A) is too small, good flexibility and transparency cannot be obtained. On the other hand, when the content of the propylene-based resin composition (A) is too large, there is a possibility that the thinning at the time of secondary processing such as heat sealing may occur more remarkably.

(2) Ethylene-α-olefin copolymer (B)
(2-1) Characteristics of ethylene-α-olefin copolymer (B) Ethylene-α used as one component of propylene resin composition (X) of intermediate layer (1) of the propylene resin multilayer sheet of the present invention The olefin copolymer (B) (hereinafter sometimes referred to as component (B)) is a copolymer obtained by copolymerizing ethylene and an α-olefin, preferably having 3 to 20 carbon atoms. Preferred examples of the α-olefin include those having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and 1-heptene. The ethylene-α-olefin copolymer (B) is a component that functions to improve the transparency and flexibility of the propylene-based resin composition (X), and includes the following (Bi) to (B-ii): ) Must be satisfied.

The propylene-based resin multilayer sheet of the present invention is required to have flexibility and transparency. Regarding the transparency, when the refractive index of the ethylene-α-olefin copolymer (B) is significantly different from that of the propylene-based resin composition (A), the transparency of the obtained sheet is deteriorated, so the refractive index is adjusted. It is also important. The refractive index can be controlled by the density, and in order to obtain the transparency required in the present invention, it is important that the density is in a specific range.
Moreover, in order to reinforce the further low temperature impact resistance of a propylene-type resin composition (A), addition of an ethylene-alpha-olefin copolymer (B) is required.

(Bi) Density The ethylene-α-olefin copolymer (B) used in the present invention needs to have a density in the range of 0.860 to 0.910 g / cm ³ .
If the density is too low, the difference in refractive index is increased and the transparency is deteriorated. Therefore, when the density is less than 0.860 g / cm ³ , the transparency necessary for the present invention cannot be ensured.
On the other hand, if the density is too high, due to the lack of flexibility in the crystallinity is high, must be at 0.910 g / cm ³ or less, preferably 0.905 g / cm ³ or less, more preferably 0.900 g / cm ³ or less.
Here, the density is a value measured according to JIS K7112.

(B-ii) Melt flow rate MFR (B) of ethylene-α-olefin copolymer (B)
The intermediate layer (1) of the present invention needs to have appropriate fluidity in order to ensure moldability. Therefore, if the melt flow rate MFR (190 ° C., 2.16 kg) (hereinafter sometimes referred to as MFR (B)) of the ethylene-α-olefin copolymer (B) is too low, the fluidity is insufficient. Transparency is reduced due to poor dispersion. Therefore, MFR (B) needs to be 0.1 g / 10 min or more, preferably 0.5 g / 10 min or more, more preferably 1.5 g / 10 min or more, particularly 2 g / 10 min. That's it.
On the other hand, if the MFR (B) is too high, the molding is unstable and the film thickness varies. Therefore, MFR (B) needs to be 20 g / 10 min or less, preferably 10 g / 10 min or less, and particularly preferably 9 g / 10 min or less.
Here, MFR is a value measured according to JIS K7210.

(2-2) Method for producing ethylene-α-olefin copolymer (B) The ethylene-α-olefin copolymer (B) used in the present invention is different in refractive index from the propylene-based resin composition (A). In order to reduce the density, it is necessary to reduce the density. Further, in order to suppress stickiness and bleed out, it is desirable that the distribution of crystallinity and molecular weight is narrow. Therefore, it is desirable to use a metallocene catalyst capable of narrowing crystallinity and molecular weight distribution for the production of the ethylene-α-olefin copolymer (B).
The metallocene catalyst and the polymerization method will be described below.

(I) Metallocene-based catalyst As the metallocene catalyst, various known catalysts used for polymerization of ethylene-α-olefin copolymers can be used.
Specific examples include metallocene catalysts described in JP-A-58-19309, JP-A-59-95292, JP-A-60-35006, and JP-A-3-16388. .

(Ii) Polymerization method Specific polymerization methods include a slurry method, a gas phase fluidized bed method and a solution method in the presence of these catalysts, or a pressure of 200 kg / cm ² or more and a polymerization temperature of 100 ° C. or more. And high pressure bulk polymerization. A preferable production method includes high-pressure bulk polymerization.
In addition, an ethylene-alpha-olefin copolymer (B) can also be suitably selected from what is marketed as a metallocene polyethylene, and can also be used. As commercial products, trade names “Affinity” and “engage” manufactured by DuPont Dow, trade names “KERNEL” manufactured by Nippon Polyethylene Co., Ltd., and trade names “EXACT” manufactured by ExxonMobil are used. Etc. In these uses, a grade satisfying the density and MFR which are the requirements of the present invention may be appropriately selected.

(2-3) Ratio of ethylene-α-olefin copolymer (B) in intermediate layer configuration The proportion of ethylene-α-olefin copolymer (B) in the intermediate layer configuration is determined based on the propylene resin composition (A ) And the ethylene-α-olefin copolymer (B) in a total amount of 100 wt%, it is necessary to be in the range of 10 to 40 wt%.
When there is too little content of an ethylene-alpha-olefin copolymer (B), provision of low temperature impact resistance is inadequate. On the other hand, when the content of the ethylene-α-olefin copolymer (B) is excessively large, the thickness of the sheet is uneven and a sheet having a good appearance cannot be obtained.
Therefore, the proportion of the ethylene-α-olefin copolymer (B) in the intermediate layer structure needs to be in the range of 10 to 40 wt%, and in the case of less than 10 wt%, flexibility is insufficient. In the case where it exceeds 40 wt%, the moldability is insufficient, so that it cannot be used. The preferable content of the ethylene-α-olefin copolymer (B) is 15 to 35 wt% with respect to 100 wt% of the total amount of the propylene-based resin composition (A) and the ethylene-α-olefin copolymer (B). It is.

(3) Propylene resin (C)
(3-1) Properties of propylene-based resin (C) The propylene-based resin (C) preferably used as a component of the propylene-based resin composition (X) of the intermediate layer of the present invention has moldability, poor appearance, and reduced thickness. Used as an inhibitory component.
The propylene resin composition (A) used as the main component of the propylene resin composition (X) of the intermediate layer is extremely effective for imparting high flexibility and transparency to the laminated sheet. Since the -α-olefin random copolymer (A1) is a resin having a relatively low melting point, there are few high crystal components, and there are problems such as thinning during heat sealing. In particular, what is obtained using a metallocene catalyst has a sharp crystallinity distribution.

Therefore, if the crystallinity distribution of the propylene-based resin composition (A) is expanded and the relatively high crystal component is increased, the low crystal component is inevitably increased. As a result, the bleed out to the surface of the laminated sheet results. This causes problems such as stickiness and poor appearance, and is not suitable for applications requiring transparency.
By adding a specific amount of the propylene resin (C) to the propylene resin composition (A) having a small amount of the high crystal component, the high crystal component and the high molecular weight component can be added without increasing the low crystal component and the low molecular weight component. As a result, it is possible to suppress appearance defects such as thickness fluctuation and interface roughness and thinning during heat sealing without causing appearance defects such as bleed out.
The propylene-based resin (C) is preferably a propylene-based resin that satisfies the following conditions (Ci) to (C-ii), and more preferably the propylene-based (co) polymer component (C1) and propylene -A propylene resin composition comprising an ethylene random copolymer component (C2).

(Ci) Melting peak temperature Tm (C)
The propylene resin (C) preferably has a melting peak temperature (Tm (C)) of 6 from the melting peak temperature (Tm (A1)) of the propylene-α-olefin random copolymer component (A1). It is a propylene-based resin that has a high temperature of ℃ or higher. By increasing the melting peak temperature by 6 ° C. or more, the resulting multilayer sheet can be given a function of suppressing thinning during heat sealing without causing appearance defects such as bleed out. It is more preferable that Tm (C) is higher than Tm (A1) by 10 ° C. or more, particularly 20 ° C. or more.
The specific melting peak temperature Tm (C) of the component (C) is preferably in the range of 150 to 170 ° C, more preferably 155 to 167 ° C. If Tm (C) is less than 150 ° C., the high crystal component is insufficient, the fluidity cannot be sufficiently lowered, and the thinning suppression effect may not be obtained. Those having a Tm (C) exceeding 170 ° C. are difficult to produce industrially. More preferable Tm (C) is 155 to 165 ° C.

(C-ii) Melt flow rate MFR (C)
In addition, it is important for the propylene-based resin (C) to have an appropriate fluidity in order to ensure moldability. MFR (C)) is preferably in the range of 0.5 to 30 g / 10 minutes, more preferably 15 g / 10 minutes, even more preferably 12 g / 10 minutes, and particularly preferably MFR. The range is 2.5 to 12 g / 10 minutes.
When the MFR (C) is less than 0.5 g / 10 minutes, the dispersion is deteriorated and an appearance defect called gel or fish eye is likely to be caused. On the other hand, when it exceeds 30 g / 10 minutes, it is easy to produce the problem on physical properties, such as a softness | flexibility fall.
Here, MFR is a value measured according to JIS K7210.

(3-2) A composition comprising a propylene-based (co) polymer component (C1) and a propylene-ethylene random copolymer (C2) The propylene-based resin (C) is propylene that satisfies the following condition (C1-i) It is more preferable that the composition is composed of a system (co) polymer component (C1) and a propylene-ethylene random copolymer component (C2) that satisfies the following conditions (C2-i). In addition, the following (C-iii) It is preferable that the propylene resin (C) satisfies the condition of

  Here, the propylene-based (co) polymer component (C1) is a polypropylene-based component and a highly crystalline component. The propylene-based (co) polymer component (C1) (hereinafter sometimes referred to as component (C1)) has a higher melting peak temperature than the propylene-based resin composition (A), and the propylene-based resin composition (A). At the temperature at which melts and starts melt flow, it is in a crystalline state (solid state) and has the effect of suppressing the melt flow of the propylene-based resin composition (A). It is an effective ingredient to suppress. Therefore, the propylene-based (co) polymer component (C1) needs to be a polypropylene or a propylene-ethylene copolymer made of a copolymer having higher crystallinity than the propylene-based resin composition (A). However, the addition of the propylene-based (co) polymer component (C1) increases the crystallinity of the entire intermediate layer, resulting in a loss of flexibility. Therefore, by adding a propylene-ethylene random copolymer component (C2) (hereinafter also referred to as component (C2)), which is a propylene-ethylene random copolymer, which is a low crystalline component, flexibility is improved. It is effective to impart flexibility to the entire laminated sheet. That is, the propylene-ethylene random copolymer component (C2) is an effective component for suppressing the increase in rigidity due to the addition of the propylene-based (co) polymer component (C1), which is a highly crystalline component.

(C1-i) Ratio of component (C1) and component (C2) in propylene-based resin (C) Propylene-based resin (C) is a component ratio of propylene-based (co) polymer component (C1) (hereinafter referred to as W (Also referred to as (C1).) Is a mixture comprising 40 to 70 wt% and a component ratio of the ethylene-propylene copolymer component (C2) (hereinafter also referred to as W (C2)) of 30 to 60 wt%. Although it may exist, what is obtained by multistage polymerization in the point which disperse | distributes ethylene-propylene copolymer component (C2) uniformly finely is preferable.
Since the ethylene-propylene copolymer component (C2) is a low crystal component, if there is too much W (C2), it is difficult to obtain a thinning suppression effect, and if there is too little W (C2), flexibility is impaired. End up. Here, W (C1) and W (C2) can be obtained from the material balance.

(C2-i) Ethylene content (E [C2])
The propylene-ethylene random copolymer component (C2) is a flexibility-imparting component necessary to minimize the increase in rigidity due to the addition of the propylene-based (co) polymer component (C1), which is a highly crystalline component. Therefore, since the propylene-ethylene random copolymer component (C2) is controlled by the ethylene content (hereinafter sometimes referred to as E [C2]), the ethylene content E [C2] is set to 15 to 40 wt%. It is preferable to do.
If the ethylene content E [C2] is less than 15 wt%, it is in a region compatible with propylene, so that it is difficult to obtain a sufficient flexibility imparting effect when added in a small amount, and when the ethylene content exceeds 40 wt%. Further, the ethylene content E [C2] is excessively increased and the transparency of the entire intermediate layer (1) is likely to deteriorate.

(C-iii) Intrinsic viscosity ratio of component (C1) and component (C2) in component (C) In tetralin at 135 ° C. of propylene-ethylene random copolymer component (C2) in propylene-based resin (C) The measured intrinsic viscosity [η] C2 (hereinafter sometimes referred to as [η] C2) is 1.7 to 6.5 dl / g, preferably 1.7 to 4.0 dl / g, and the same. The intrinsic viscosity ratio [η] C2 / [η] C1 with the intrinsic viscosity [η] C1 (hereinafter sometimes referred to as [η] C1) of the propylene-based (co) polymer component (C1) measured under the conditions is , 0.6 to 1.2, particularly preferably in the range of 0.6 to 1.1.
[Η] C1 particularly affects processing characteristics such as sheet formability, and [η] C2 / [η] C1 is a propylene-based (co) polymer component of a propylene-ethylene random copolymer component (C2) ( C1) Affects dispersibility in the medium. If [η] C1 is too large, the formability of the sheet tends to deteriorate, which causes a problem in production. On the other hand, if [η] C2 is too small, sufficient flexibility is difficult to obtain, and if [η] C2 is too large, the transparency tends to deteriorate.

In addition, when component (C1) and component (C2) are continuously produced to obtain component (C), [η] C2 in component (C) cannot be directly measured, and thus can be directly measured [η]. It is obtained from the intrinsic viscosity [η] C (hereinafter also referred to as [η] C) of C1 and the component (C) and W (C2) by the following formula.
[Η] C2 =
{[Η] C- (1-W (C2) / 100) [η] C1} / (W (C2) / 100)
Here, continuously producing means that the component (C1) is produced in the first stage described later (first process), and then the component (C2) is produced continuously in the second stage (second process). Means.

Further, in the propylene-based resin (C) used in the present invention, the weight ratio (W (C2) / W (C1)) between W (C1) and W (C2) and the intrinsic viscosity ratio ([η ] ([Η] C2 / [η] C1) × (W (C1) / W (C2))) is 0.2 to 4.5, preferably 0.6 to 4 Preferably it is in the range of 0.0.
The product of the weight ratio and the intrinsic viscosity ratio indicates the dispersion state of the component (C2) dispersed in the component (C1), and being within the above range indicates that the domain of the component (C2) is molded. It is an indispensable condition to show a specific dispersion structure that sometimes exists in a state where the domain alone is stretched in the flow direction, or is connected to at least one other domain, and the value is within the above numerical range. It is preferable because the transparency and flexibility of the obtained sheet are improved.

(3-3) Producing method of propylene-based resin (C) The propylene-based resin (C) may be produced by any method as long as the above properties are satisfied. When the composition is produced from the propylene-based (co) polymer (C1) and the propylene-ethylene random copolymer (C2), the separately produced propylene-based (co) polymer (C1) and propylene-ethylene The propylene-based resin (C) may be produced from the random copolymer (C2) using a mixing device, and the propylene-based (co) polymer component (C1) is produced in the first step, followed by the second step. In the step, the propylene-ethylene random copolymer component (C2) may be produced in the presence of the propylene-based (co) polymer component (C1) to continuously produce the propylene-based resin (C).
As specific production methods, the production methods described in JP-A-2006-35516 and JP-A-2001-172454 can be preferably exemplified. It is assumed that it is incorporated in the specification.
In addition, propylene-type resin (C) can also be suitably selected from what is marketed, and can also be used. Examples of commercially available products include “NOVATECPP” (trade name) manufactured by Nippon Polypro Co., Ltd., “NEWCON” (trade name) manufactured by Nippon Polypro Corporation, and “ZELAS” (trade name) manufactured by Mitsubishi Chemical Corporation. In these uses, grades satisfying the melting peak temperature, MFR, and intrinsic viscosity ratio, which are the conditions in the present invention, may be appropriately selected.

  In the present specification, when the propylene-based resin composition is produced by the sequential polymerization method by the two-stage polymerization of the first step and the second step, the component 1 (hereinafter referred to as W1) obtained by the first step is used. And the amount of component 2 (hereinafter also referred to as W2) in the second step can be determined by temperature-temperature elution fractionation (TREF), and the ethylene content (or α) of component 1 and component 2 can be obtained. -Olefin content) E [W1], E [W2] can be determined by NMR measurement.

(A) Identification of W1 and W2 by temperature-temperature elution fractionation method (TREF) A technique for evaluating the crystalline distribution of propylene-ethylene random copolymer, etc. by temperature-temperature elution fractionation method (TREF) is well known to those skilled in the art. For example, a detailed measurement method is shown in the following document.
G. Glockner, J. et al. Appl. Polym. Sci. : Appl. Polym. Symp. 45, 1-24 (1990)
L. Wild, Adv. Polym. Sci. 98, 1-47 (1990)
J. et al. B. P. Soares, A .; E. Hamielec, Polymer; 36, 8, 1639-1654 (1995)

Specifically, in the present invention, the measurement is performed as follows.
A sample is dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) at 140 ° C. to obtain a solution. This is introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to −15 ° C. at a rate of 4 ° C./min, and held for 60 minutes. Then, a component of -15 ° C o-dichlorobenzene (containing 0.5 mg / ml BHT), which is a solvent, flows through the column at a flow rate of 1 ml / min, and is dissolved in -15 ° C o-dichlorobenzene in the TREF column. Is eluted for 10 minutes, and then the column is linearly heated to 140 ° C. at a heating rate of 100 ° C./hour to obtain an elution curve.
In the obtained elution curve, component 1 and component 2 show their elution peaks at the respective temperatures T (W1) and T (W2) due to the difference in crystallinity, and the difference is sufficiently large, so that the intermediate temperature T (W3 ) (= {T (W1) + T (W2)} / 2).
Here, if the integrated amount of the components eluted before T (W3) is defined as W (W2) wt%, and the integrated amount of the portion eluted at T (W3) or higher is defined as W (W1) wt%, W (W2) Corresponds to the amount of the component (W2), and the integrated amount W (W1) of the component eluted at T (W3) or higher corresponds to the amount of the component (W1) having relatively high crystallinity.

The equipment and specifications used for the measurement are shown below.
(TREF part)
TREF column: 4.3 mmφ × 150 mm stainless steel column Column packing material: 100 μm Surface inactive glass beads Heating method: Aluminum heat block Cooling method: Peltier element (Peltier element is cooled by water)
Temperature distribution: ± 0.5 ° C
Temperature controller: Chino Corporation Digital Program Controller KP1000 (Valve Oven)
Heating method: Air bath oven Measurement temperature: 140 ° C
Temperature distribution: ± 1 ° C
Valve: 6-way valve 4-way valve (sample injection part)
Injection method: Loop injection method Injection volume: Loop size 0.1ml
Inlet heating method: Aluminum heat block measurement temperature: 140 ° C

(Detection unit)
Detector: Fixed wavelength infrared detector FOXBORO MIRAN 1A
Detection wavelength: 3.42 μm
High-temperature flow cell: LC-IR micro flow cell Optical path length 1.5mm
Window shape 2φ × 4mm long circle Synthetic sapphire window measurement temperature: 140 ° C
(Pump part)
Liquid feed pump: SSC-3461 pump manufactured by Senshu Kagaku Co. [Measurement conditions]
Solvent: o-dichlorobenzene (containing 0.5 mg / ml BHT)
Sample concentration: 5 mg / ml
Sample injection volume: 0.1 ml
Solvent flow rate: 1 ml / min

(A) Identification of E [W1] and E [W2] The ethylene (or α-olefin) content E [W1] and the ethylene content E [W2] of each component are determined by using a preparative fractionation device. Each component is separated by a fractionation method, and the ethylene (or α-olefin) content of each component is determined by NMR.
The temperature rising column fractionation method is a measurement method disclosed in, for example, Macromolecules 21 314-319 (1988). Specifically, the following method was used in the present invention.

(C) Temperature rising column fractionation A cylindrical column having a diameter of 50 mm and a height of 500 mm is filled with a glass bead carrier (80 to 100 mesh) and maintained at 140 ° C. Next, 200 ml of a sample o-dichlorobenzene solution (10 mg / ml) dissolved at 140 ° C. is introduced into the column. Thereafter, the temperature of the column is cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./hour. After holding at 0 ° C. for 1 hour, the column temperature is heated to T (W3) (obtained for TREF measurement) at a heating rate of 10 ° C./hour and held for 1 hour. Note that the temperature control accuracy of the column through a series of operations is ± 1 ° C.
Next, while maintaining the column temperature at T (W3), by flowing 800 ml of T- (W3) o-dichlorobenzene at a flow rate of 20 ml / min, components soluble in T (W3) present in the column are obtained. Elute and collect.
Next, the column temperature is increased to 140 ° C. at a rate of temperature increase of 10 ° C./min, left at 140 ° C. for 1 hour, and then 800 ml of o-dichlorobenzene as a solvent at 140 ° C. is flowed at a flow rate of 20 ml / min. , T (W3) is eluted and recovered.
The polymer-containing solution obtained by fractionation is concentrated to 20 ml using an evaporator and then precipitated in 5 times the amount of methanol. The precipitated polymer is collected by filtration and dried overnight in a vacuum dryer.

(D) Measurement of ethylene content by 13C-NMR The ethylene content E [W2] for each component (W2) obtained by the above fractionation was measured according to the following conditions by the proton complete decoupling method. Obtained by analyzing the spectrum.
Model: GSX-400 manufactured by JEOL Ltd. or equivalent device (carbon nuclear resonance frequency of 100 MHz or more)
Solvent: o-dichlorobenzene / heavy benzene = 4/1 (volume ratio)
Concentration: 100 mg / ml
Temperature: 130 ° C
Pulse angle: 90 °
Pulse interval: 15 seconds Integration number: 5,000 times or more The attribution of the spectrum may be performed with reference to Macromolecules 17 1950 (1984), for example. The spectral attributions measured under the above conditions are shown in Table 1. In the table, symbols such as Sαα follow the notation of Carman et al. (Macromolecules 10 536 (1977)), P represents a methyl carbon, S represents a methylene carbon, and T represents a methine carbon.

Hereinafter, when “P” is a propylene unit in a copolymer chain and “E” is an ethylene unit, six types of triads of PPP, PPE, EPE, PEP, PEE, and EEE may exist in the chain. As described in Macromolecules 15 1150 (1982) and the like, the concentration of these triads and the peak intensity of the spectrum are linked by the following relational expressions (1) to (6).
[PPP] = k × I (Tββ) (1)
[PPE] = k × I (Tβδ) (2)
[EPE] = k × I (Tδδ) (3)
[PEP] = k × I (Sββ) (4)
[PEE] = k × I (Sβδ) (5)
[EEE] = k × {I (Sδδ) / 2 + I (Sγδ) / 4} (6)
Here, [] indicates the fraction of triads, for example, [PPP] is the fraction of PPP triads in all triads.
Therefore, [PPP] + [PPE] + [EPE] + [PEP] + [PEE] + [EEE] = 1 (7)
It is. Further, k is a constant, I indicates the spectral intensity, and for example, I (Tββ) means the intensity of the 28.7 ppm peak attributed to Tββ.
By using the relational expressions (1) to (7) above, the fraction of each triad is obtained, and the ethylene content is obtained from the following expression.
Ethylene content (mol%) = ([PEP] + [PEE] + [EEE]) × 100

  The propylene-ethylene random copolymer contains a small amount of propylene heterogeneous bonds (2,1-bonds and / or 1,3-bonds), thereby producing the minute peaks shown in Table 2.

In order to obtain an accurate ethylene content, it is necessary to include these peaks derived from heterogeneous bonds in the calculation, but it is difficult to completely separate and identify the peaks derived from heterogeneous bonds, and the amount of heterogeneous bonds is small. Therefore, the ethylene content of the present invention is obtained by using the relational expressions (1) to (7) as in the analysis of the copolymer produced with a Ziegler-Natta catalyst that does not substantially contain a heterogeneous bond. I will do it.
Conversion from mol% to wt% of ethylene content is performed using the following formula.
Ethylene content (% by weight)
= (28 * X / 100) / {28 * X / 100 + 42 * (1-X / 100)} * 100
(Here, X is the ethylene content in mol%.)

(3-4) Proportion of propylene-based resin (C) in intermediate layer component The proportion of propylene-based resin (C) in the intermediate layer (1) is the above-described propylene-based resin composition (A) and ethylene-α-. It is preferable that it is the range of 1-25 wt% with respect to a total of 100 wt% of an olefin copolymer (B) and propylene-type resin (C). The propylene-based (co) polymer component (C1) constituting the propylene-based resin (C) has a melting peak temperature higher than that of the component (A), and therefore maintains a crystalline state even at a temperature at which the component (A) melts. In addition, the propylene-ethylene random copolymer component (C2) constituting the component (C) is suppressed from flowing and the rigidity of the propylene-ethylene random copolymer component (C2) constituting the component (C) is minimized by adding the component (C1) which is a highly crystalline component. It has the effect of imparting flexibility to keep it to the limit.
At this time, if the amount of the propylene-based resin (C) is too small, the high crystalline component is insufficient, and it is difficult to obtain a sufficient thinning-inhibiting effect. 5 wt% or more. On the other hand, if the amount of the propylene resin (C) is too large, physical properties such as flexibility and transparency are likely to deteriorate significantly, and it is difficult to satisfy the quality required for the resin composition of the present invention. Therefore, it is preferably 25 wt% or less, more preferably 20 wt% or less.

(3-5) Proportion of components (A) and (B) when propylene resin (C) is contained in the intermediate layer Propylene resin composition when propylene resin (C) is contained in the intermediate layer component (A ), As the proportion of the ethylene-α-olefin copolymer (B), the component (A) is preferably 45 to 89 wt%, more preferably 100 wt% of the total of the components (A) to (C). Is 45 to 85 wt%, particularly preferably 50 to 80 wt%. Similarly, the component (B) is preferably 15 to 25 wt% with respect to the total of 100 wt% of the components (A) to (C).

2. Outer layer (2)
The outer layer (2) of the multilayer sheet of the present invention is formed from a propylene-based resin composition (Y).
(1) Properties of propylene-based resin composition (Y) Propylene-based resin composition (Y) used as the outer layer (2) of the propylene-based resin multilayer sheet of the present invention (hereinafter also referred to as component (Y)). Must have excellent transparency, flexibility, heat resistance, and impact resistance. In order to obtain transparency and flexibility as a multilayer sheet, not only the intermediate layer (1) but also the outer layer (2) must be made flexible and transparent. In addition, the outer layer (2) must also have heat resistance, must not be deformed even by heat treatment such as sterilization or sterilization, and must not stick to the heat seal bar in heat sealing that is a secondary process. is there. In addition, it is necessary to suppress the occurrence of notches (breaking origin) in the sheet base material in the bag drop test after processing the heat-treatment packaging bag, and also to have impact resistance.

In order to satisfy these requirements at a high level, the propylene-based resin composition (Y) may be referred to as a propylene-based resin (D) (hereinafter referred to as component (D)) that satisfies the following condition (Di). ).
Preferably, the propylene-based (co) polymer component (D1) (hereinafter sometimes referred to as the component (D1)) that satisfies the following conditions (D-ii) and (D1-i) and the following (D2- A composition comprising a propylene-ethylene random copolymer component (D2) (hereinafter sometimes referred to as component (D2)) that satisfies the conditions i) to (D2-iii) is preferred.
The propylene-based resin (D) itself has good impact resistance, but in order to give impact resistance at a low temperature of 0 to 5 ° C., the following ethylene-α-olefin copolymer is used. (D3) (hereinafter also referred to as component (D3)) may be added.

(Di) Melting peak temperature Tm (D)
The melting peak temperature Tm (D) of the propylene-based resin (D) needs to be in the range of 135 to 170 ° C., preferably 136 to 165 ° C., more preferably 136 to 163 ° C.
When Tm (D) is less than 135 ° C., the heat resistance is insufficient, and there is a risk of deformation if a heat treatment such as sterilization or sterilization is performed. Those having a Tm (D) exceeding 170 ° C. are difficult to produce industrially.

(D-ii) Melt flow rate MFR (D)
The propylene-based resin (D) needs to have appropriate fluidity in order to obtain easy moldability that does not cause interface roughness and surface roughness during lamination and does not cause thickness fluctuation. The melt flow rate MFR (230 ° C., 2.16 kg load) (hereinafter sometimes referred to as MFR (D)) is preferably in the range of 4 to 15 g / 10 min, more preferably 4 5-10 g / 10 min.
When the MFR (D) is less than 4 g / 10 minutes, the interface roughening and the surface roughening are likely to occur, and a sheet having a good appearance may not be obtained. On the other hand, when the MFR (D) exceeds 15 g / 10 minutes, the thickness is likely to fluctuate and the moldability is often difficult.
Here, MFR is a value measured according to JIS K7210.

(2) Composition comprising propylene-based (co) polymer component (D1) and propylene-ethylene random copolymer (D2) The propylene-based resin (D) is a propylene-based resin that satisfies the following (D1-i) A composition comprising a (co) polymer component (D1) and a propylene-ethylene random copolymer (D2) that satisfies the following conditions (D2-i) to (D2-iii) is preferable.
Here, the component (D1) is a polypropylene component and is a highly crystalline component. The component (D1) has a higher melting peak temperature than the component (D2) and has heat resistance. Since only the component (D1) is highly rigid, the flexibility of the multilayer sheet of the present invention is impaired. Therefore, imparting flexibility by adding the component (D2) which is a propylene-ethylene random copolymer and is a low crystal component is effective for softening the outer layer (2). That is, the component (D2) is an effective component for suppressing an increase in rigidity due to the component (D1) that is a highly crystalline component.

(D1-i) Ratio of component (D1) in propylene-based resin (D) The propylene-based resin (D) is sometimes referred to as a propylene-based (co) polymer component (D1) (hereinafter referred to as component (D1)). ) Component ratio (hereinafter also referred to as W (D1)) is 40 to 70 wt%, and component ratio of propylene-ethylene random copolymer component (D2) (hereinafter also referred to as component (D2)). (Hereinafter, it may be referred to as W (D2).) May be a mixture of 30 to 60 wt%, but those obtained by multi-stage polymerization are preferable in that the component (D2) is uniformly and finely dispersed.
Since the component (D2) is a low crystal component, if there is too much W (D2), it is difficult to obtain heat resistance, and if there is too little W (D2), flexibility is not sufficient.
Here, W (D1) and W (D2) can be obtained from the material balance.

(D2-i) Ethylene content (E [D2])
The propylene-ethylene random copolymer component (D2) is a flexibility-imparting component necessary to minimize the increase in rigidity due to the component (D1), which is a highly crystalline component. Therefore, since the component (D2) is controlled by the ethylene content (hereinafter sometimes referred to as E [D2]), the ethylene content is preferably 15 to 40 wt%.
If the ethylene content is less than 15 wt%, there is a problem that it is difficult to obtain a sufficient flexibility imparting effect because it is a compatible region with propylene. The deterioration of the transparency of the entire outer layer sheet is remarkable.

(D2-ii) Intrinsic viscosity Intrinsic viscosity [η] (hereinafter referred to as [η] D2) measured in 135 ° C. tetralin of the propylene-ethylene random copolymer component (D2) in the propylene-based resin (D) Is 1.7 to 6.5 dl / g, preferably 1.7 to 4.0 dl / g, and the intrinsic viscosity [η] of the component (D1) measured under the same conditions (hereinafter referred to as [ The intrinsic viscosity ratio [η] D2 / [η] D1 is preferably in the range of 0.6 to 1.2, particularly 0.6 to 1.1.
[Η] D2 particularly affects processing characteristics such as sheet formability, and [η] D2 / [η] D1 affects the dispersibility of component (D2) into component (D1). If [η] D2 is too large, the formability of the sheet is deteriorated, which causes a problem in production. On the other hand, if [η] D2 is too small, sufficient flexibility cannot be obtained, and if [η] D2 is too large, the transparency is deteriorated.

When the component (D1) and the component (D2) are continuously produced to obtain the propylene-based resin (D), [η] D2 in the propylene-based resin (D) cannot be directly measured, and thus can be directly measured. It calculates | requires by the following formula from [(eta)] D1 and intrinsic viscosity [(eta)] D (henceforth [(eta)] D) of component (D)), and W (D2).
[Η] D2 =
{[Η] D− (1−W (D2) / 100) × [η] D1} / (W (D2) / 100)
Here, continuously producing means that the component (D1) is produced in the first stage described later (first process), and then the component (D2) is produced continuously in the second stage (second process). means.

(D2-iii) Product of weight ratio and limiting viscosity ratio of (D1) and (D2) In the propylene-based resin composition (D) used in the present invention, the weight of W (D1) and W (D2) Product ([η] D2 / [η] D1) × (W (D2) / W (D1)) and the intrinsic viscosity ratio ([η] D2 / [η] D1) of the above-described quantitative components) × (W (D1) / W (D2)) is preferably in the range of 0.2 to 4.5, more preferably 0.6 to 4.0.
The product of the weight ratio and the intrinsic viscosity ratio indicates the dispersion state of the component (D2) dispersed in the component (D1), and being within the above range indicates that the domain of the component (D2) is molded. It is a condition for showing a specific dispersion structure that sometimes exists in a state where the domain alone is stretched in the flow direction or is connected to another domain at least at one place, and the value is within the above numerical range. And transparency and flexibility of the obtained sheet are improved.

(3) Method for Producing Propylene Resin Composition (D) The propylene resin (D) used in the present invention may be produced by any method as long as the above properties are satisfied. When producing a composition comprising a propylene-based (co) polymer component (D1) and a propylene-ethylene random copolymer (D2), the propylene-based (co) polymer (D1) and propylene produced separately are produced. -You may manufacture a propylene-type resin (D) from a ethylene random copolymer (D2) using a mixing apparatus.
In addition, a propylene-based (co) polymer component (D1) is produced, and then a propylene-ethylene random copolymer component (D2) is produced in the presence of the propylene-based (co) polymer component (D1). The system resin (D) may be continuously produced. As specific manufacturing methods, the manufacturing methods described in JP-A-2006-35516 and JP-A-2001-172454 can be preferably exemplified. It is assumed that it was taken in.
In addition, a propylene-type resin composition (D) can also be suitably selected from what is marketed, and can also be used. Examples of commercially available products include “NOVATECPP” (trade name) manufactured by Nippon Polypro Co., Ltd., “NEWCON” (trade name) manufactured by Nippon Polypro Corporation, and “ZELAS” (trade name) manufactured by Mitsubishi Chemical Corporation. In these uses, a grade satisfying the melting peak temperature, MFR, and intrinsic viscosity ratio, which are the conditions of the present invention, may be appropriately selected.

(4) Ethylene-α-olefin copolymer (D3)
The propylene-based resin (D) itself has good impact resistance, but in order to impart impact resistance at a low temperature of 0 to 5 ° C., the following ethylene-α-olefin copolymer (D3 ) May be added.
The ethylene-α-olefin copolymer (D3) that can be used for the outer layer (2) of the propylene-based resin multilayer sheet of the present invention is obtained by copolymerizing ethylene and preferably an α-olefin having 3 to 20 carbon atoms. Preferred examples of the α-olefin include those having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and 1-heptene. . The ethylene-α-olefin copolymer (D3) is a component that functions to improve the low-temperature impact resistance of the propylene-based resin composition (Y), and satisfies the following condition (D3-i). preferable.

(D3-i) Density The ethylene-α-olefin copolymer (D3) that can be suitably used in the present invention preferably has a density in the range of 0.860 to 0.910 g / cm ³ . If the density is too low, the difference in refractive index becomes large and the transparency deteriorates. Therefore, when it is less than 0.860 g / cm ³ , it is difficult to ensure the transparency required for the present invention.
On the other hand, if the density becomes too high, the crystallinity becomes high, resulting in insufficient low-temperature impact resistance. Also, as in the case where the density becomes too low, the refractive index difference becomes large even if the density becomes too high. Therefore, transparency is likely to deteriorate. More preferably, it is 0.905 g / cm ³ or less, and particularly preferably 0.900 g / cm ³ or less.
Here, the density is a value measured according to JIS K7112.

(5) Production method of ethylene-α-olefin copolymer (D3) The ethylene-α-olefin copolymer (D3) that can be suitably used in the present invention is different in refractive index from the propylene-based resin (D). In order to reduce the density, it is necessary to match the density. Further, in order to suppress stickiness and bleed out, it is desirable that the crystallinity and molecular weight distribution are narrow. Therefore, it is desirable to use a metallocene catalyst capable of narrowing crystallinity and molecular weight distribution for the production of the ethylene-α-olefin copolymer (D3).

As the metallocene catalyst, various known catalysts used for the polymerization of ethylene-α-olefin copolymers can be used, and those similar to those described for the ethylene-α-olefin copolymer (B) are used. Specific polymerization methods include a slurry method, a gas phase fluidized bed method and a solution method in the presence of these catalysts, or a high-pressure bulk at a pressure of 200 kg / cm ² or higher and a polymerization temperature of 100 ° C. or higher. Examples thereof include a polymerization method. A preferable production method includes high-pressure bulk polymerization.
In addition, an ethylene-alpha-olefin copolymer (D3) can also be suitably selected from what is marketed as a metallocene polyethylene, and can also be used. As commercial products, trade names “Affinity” and “engage” manufactured by DuPont Dow, trade names “KERNEL” manufactured by Nippon Polyethylene Co., Ltd., and trade names “EXACT” manufactured by ExxonMobil are used. Etc.
In these uses, a grade satisfying the density, which is a condition of the present invention, may be appropriately selected.

(6) Component ratio in propylene-based resin composition (Y) in outer layer (2) When using ethylene-α-olefin copolymer (D3) that can be suitably used in the present invention, propylene-based resin (D) The proportion of the component (D3) in the outer layer (2) is preferably in the range of 80 to 99 wt%, and the proportion of the component (D3) in the outer layer (2) is preferably in the range of 1 to 20 wt%. More preferably, the content of the component (D) is 85 to 95 wt%, and the content of the component (D3) is 5 to 15 wt%.
When the content of the component (D) is less than 80 wt%, that is, when the content of the component (D3) is 20 wt% or more, the heat resistance is insufficient and there is a risk of deformation in the heat treatment step. When the content of the component (D) is 99 wt% or more, that is, when the content of the component (D3) is less than 1 wt%, the low temperature impact resistance imparting effect is insufficient.

3. Inner layer (3)
The multilayer sheet of the present invention is a multilayer sheet comprising at least three layers having the inner layer (3) in the order of the outer layer (2), the intermediate layer (1), and the inner layer (3). It is preferably formed from the following propylene-based resin composition (Z).

(1) Properties of propylene-based resin composition (Z) The propylene-based resin composition (Z) (hereinafter sometimes referred to as component (Z)) used as the inner layer (3) of the multilayer sheet is transparent and flexible. And heat resistance to prevent inner surface fusion. In addition, since the inner layer (3) is in contact with the contents, the inner layer (3) is required to have cleanness that does not contaminate the contents and easy bag making that can be heat-sealed at a low temperature.
Further, in order to obtain a strong heat seal strength, a propylene-based resin composition (G) (hereinafter also referred to as component (G)) for obtaining more flexibility, an ethylene-α-olefin copolymer ( H) (hereinafter also referred to as component (H)) and propylene-based resin composition (Z) (hereinafter also referred to as component (I)) (hereinafter also referred to as component (I)). Z)))).

(2) Propylene resin composition (Z)
The propylene resin composition (Z) of the inner layer (3) is a composition comprising a propylene resin composition (G), an ethylene-α-olefin copolymer (H), and a propylene resin (I). It is suitable for obtaining a more flexible propylene-based resin multilayer sheet.

(2-1) Properties of the propylene-based resin composition (G) The propylene-based resin composition (G) has high transparency, flexibility, and high impact resistance, and also has inner surface fusion in the overheating process. Low temperature heat sealability is required to obtain heat resistance that does not occur and easy bag making. In order to satisfy these requirements at a high level, the component (G) is a propylene-based resin composition (G) that satisfies the following conditions (G-i) and (G-ii).
(Gi) Using a metallocene-based catalyst, 50 to 60 wt% of a propylene-α-olefin random copolymer component (G1) having a melting peak temperature Tm (G1) of 125 to 135 ° C. in DSC measurement in the first step. The propylene-ethylene block copolymer obtained by sequentially polymerizing 50-40 wt% of the propylene-ethylene random copolymer component (G2) having an ethylene content (E [G2]) of 8-14 wt% in the second step It is a coalescence.
(G-ii) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the peak of the tan δ curve representing the glass transition observed in the range of −60 to 20 ° C. is simply below 0 ° C. One peak is shown.

(Gi) Basic definition of component (G) The component (G) used in the present invention uses a metallocene catalyst, and the melting peak temperature Tm (G1) in DSC measurement in the first step is 125 to 135 ° C. 50 to 60 wt% of a propylene-ethylene random copolymer component (G1) (hereinafter also referred to as component (G1)) having an ethylene content E (G1) in the range of 1.5 to 3.0 wt%, Sequentially polymerizing 50 to 40 wt% of a propylene-ethylene random copolymer component (G2) (hereinafter also referred to as component (G2)) having an ethylene content E (G2) of 8 to 14 wt% in the second step. It is obtained by. The above conditions will be described in detail in the following (i) to (vi).

(I) Melting peak temperature Tm (G1) of component (G1)
The component (G1) produced in the first step is a component that determines crystallinity in the component (G) used in the present invention. In order to improve the heat resistance of the component (G), the melting peak temperature Tm (G1) of the component (G1) (hereinafter sometimes referred to as Tm (G1)) is required to be high, but Tm ( When G1) is too high, the heat seal temperature is increased, and the bag-making property is impaired. On the other hand, if Tm (G1) is too low, the heat resistance deteriorates and inner surface fusion occurs during heat treatment such as a sterilization step. Tm (G1) needs to be in the range of 125 to 135 ° C., and preferably 128 to 133 ° C. or less.
Here, the method for measuring the melting peak temperature Tm is as described above.

(Ii) Ethylene content E (G1) of component (G1)
The melting peak temperature Tm (G1) of the component (G1) is controlled by the ethylene content, and the ethylene content E (G1) of the component (G1) in the present invention (hereinafter sometimes referred to as E (G1)). , Preferably it is the range of 1.5-3.0 wt%. When E (G1) is less than 1.5 wt%, Tm (G1) becomes too high, and the low temperature heat sealability may be impaired. When it exceeds 3.0 wt%, Tm (G1) is It may become too low, and internal fusion may occur in the sterilization and sterilization processes.

(Iii) Ratio of component (G1) in component (G) Ratio W (G1) of component (G1) in component (G) is a component that imparts heat resistance to component (G), When there is too much W (G1), a softness | flexibility, impact resistance, and transparency cannot fully be exhibited. Therefore, the ratio of the component (G1) needs to be 60 wt% or less.
On the other hand, if the proportion of the component (G1) is too small, the heat resistance is lowered even if the Tm (G1) is sufficient, and there is a risk that inner surface fusion may occur in the sterilization and sterilization processes. The ratio must be 50 wt% or more.

(Iv) Ethylene content E (G2) in component (G2)
The component (G2) produced in the second step is a component necessary for improving flexibility, impact resistance, and transparency. In general, the ethylene content in the propylene-ethylene random copolymer is decreased, so that the crystallinity is lowered and the flexibility improving effect is increased. Therefore, the ethylene content E (G2) in the component (G2) (hereinafter referred to as E (G2) may need to be 8 wt% or more. When E (G2) is less than 8 wt, sufficient flexibility cannot be exhibited, and it is preferably 10 wt% or more.
On the other hand, if E (G2) is increased too much in order to lower the crystallinity of component (G2), the compatibility of component (G1) and component (G2) decreases, and component (G2) becomes compatible with component (G1). Domains are formed without solubilization. In such a phase separation structure, if the refractive index of the matrix and the domain are different, the transparency is drastically lowered. Therefore, E (G2) of the component (G2) in the component (G) used in the present invention needs to be 14 wt% or less, preferably 12 wt% or less.

(V) The ratio of the component (G2) in the component (G) The ratio W (G2) of the component (G2) in the component (G) is too low, so that the heat resistance decreases. Therefore, it is necessary to suppress the content to 50 wt% or less.
On the other hand, if W (G2) becomes too small, the effect of improving the flexibility and impact resistance cannot be obtained, so W (G2) needs to be 40 wt% or more.
Here, W (G1) and W (G2) are values obtained by temperature rising elution fractionation (TREF), and ethylene contents E (G1) and E (G2) are obtained by NMR as described above. Value.

(G-ii) Temperature-loss tangent (tan δ) curve peak The component (G) used in the present invention is -60 to 20 ° C. in a temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA). It is necessary that the peak of the tan δ curve representing the glass transition observed in the range of 0 shows a single peak at 0 ° C. or lower.
When the component (G) has a phase separation structure, the glass transition temperature of the amorphous part contained in the component (G1) and the glass transition temperature of the amorphous part contained in the component (G2) are different from each other. Multiple. In this case, there arises a problem that the transparency is remarkably deteriorated.
Usually, the glass transition temperature in the propylene-ethylene random copolymer is observed in the range of −60 to 20 ° C., and whether or not the phase separation structure is taken is determined in the tan δ curve obtained by the solid viscoelasticity measurement in this range. Possible avoidance of the phase separation structure that affects the transparency of the sheet is brought about by having a single peak below 0 ° C.

Melt flow rate MFR (Z) of propylene resin composition (Z)
In addition, the propylene-based resin composition (Z) needs to have appropriate fluidity in order to obtain easy moldability that does not cause interface roughness or surface roughness during lamination and does not cause thickness variation. The melt flow rate MFR (230 ° C., 2.16 kg load) (hereinafter sometimes referred to as MFR (Z)), which is a measure of fluidity, is preferably in the range of 2 to 15 g / 10 min. Preferably it is 2.5-10 g / 10min.
When MFR (Z) is less than 2 g / 10 minutes, it is likely that interface roughness and surface roughness are likely to occur, and a sheet having a good appearance may not be obtained. On the other hand, when MFR (Z) exceeds 15 g / 10 min, thickness variation is likely to occur, and moldability is difficult.
Here, MFR is a value measured according to JIS K7210.

Method for Producing Component (G) The method for producing component (G) used in the present invention comprises using a metallocene catalyst to polymerize component (G1) in the first step and sequentially producing component (G2) in the second step. Although it can be obtained by polymerization, the method described in JP-A-2005-132799 can be preferably used.
Here, the solid viscoelasticity measurement method is defined in the same manner as described above.

(G) Ratio of component (G) in component (Z) The ratio of component (G) to component (Z) must be in the range of 45 to 89 wt%, preferably 40 to 80 wt%. . When the content of the component (G) is too small, good flexibility and transparency cannot be obtained. On the other hand, if the content of the component (G) is too large, more preferable impact resistance and heat resistance may not be obtained.

(2-2) Ethylene-α-olefin copolymer (H)
Characteristics of Component (H) The ethylene-α-olefin copolymer (H) contained in the propylene-based resin composition (Z) is obtained by copolymerizing ethylene and preferably an α-olefin having 3 to 20 carbon atoms. The resulting copolymer, preferably α-olefin, having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, etc. It can be illustrated. The component (H) is a component that functions to improve the transparency and flexibility of the propylene-based resin composition, and it is necessary to satisfy the following condition (Hi).
The propylene-based resin composition (Z) used in the present invention is required to have flexibility and transparency. Regarding the transparency, when the refractive index of the component (H) is significantly different from that of the component (G), the transparency of the resulting sheet is deteriorated, so it is also important to match the refractive indexes. The refractive index can be controlled by the density, and in order to obtain the transparency required in the present invention, it is important that the density is in a specific range.
The component (G) is excellent in flexibility, but the flexibility is impaired by the addition of the propylene-based resin (component (I)). Therefore, it is necessary to add a component (H) that can improve flexibility.

(Hi) Density The component (H) used in the present invention needs to have a density in the range of 0.860 to 0.900 g / cm ³ .
If the density is too low, the difference in refractive index is increased and the transparency is deteriorated. Therefore, when the density is less than 0.860 g / cm ³ , the transparency necessary for the present invention cannot be ensured.
On the other hand, if the density becomes too high, the crystallinity becomes high and the flexibility becomes insufficient, so 0.900 g / cm ³ or less is necessary, and preferably 0.885 g / cm ³ or less.
Here, the density is a value measured according to JIS K7112.

Production method of component (H) The component (H) used in the present invention needs to have a low density in order to reduce the difference in refractive index from the component (G), and further, it has no stickiness or bleed out. In order to suppress, it is desirable that crystallinity and molecular weight distribution are narrow. Therefore, it is desirable to use a metallocene catalyst capable of narrowing crystallinity and molecular weight distribution for the production of component (H).
Regarding the metallocene catalyst and the polymerization method, the description of the ethylene-α-olefin copolymer (B) can be applied as it is.
In addition, a component (H) can also be suitably selected from what is marketed as a metallocene polyethylene, and can also be used. Examples of commercially available products include DuPont Dow's trade name affinity and engagement, Nippon Polyethylene's trade name kernel, ExxonMobil's trade name EXACT, and the like.
In these uses, a grade satisfying the density, which is a condition of the present invention, may be appropriately selected.

Ratio of component (H) in component (Z) The ratio of component (H) in component (Z) needs to be in the range of 10 to 30 wt%.
When there is too little content of a component (H), provision of a softness | flexibility is inadequate and the sacrifice of a softness | flexibility by addition of propylene-type resin (I) cannot be recovered. On the other hand, if the content of the component (H) is too large, the thickness of the sheet is uneven and it is difficult to obtain a sheet having a good appearance.
Therefore, the proportion of the component (H) in the component (Z) needs to be in the range of 10 to 30 wt%, and in the case of less than 10 wt%, the flexibility is insufficient and 30 wt% is reduced. If it exceeds, the moldability is insufficient, so it cannot be used.

(2-3) Propylene resin (I)
Properties of Component (I) The propylene resin (I) used in the present invention is a component for improving moldability and a component for suppressing inner surface fusion that may occur in a heat treatment step such as a sterilization step. Used as
In the present invention, the component (G) used as the main component is extremely effective for imparting high flexibility and transparency to the laminated sheet, but is produced by a metallocene catalyst, so that the molecular weight distribution is narrow. In addition, there is a problem of causing appearance defects such as thickness fluctuation suppression during stacking and interface roughness due to a small amount of high crystalline component and high molecular weight component. In addition, the component (G) alone remains uneasy about heat resistance and is highly likely to cause inner surface fusion.
Therefore, if the molecular weight distribution of the component (G) is expanded to increase the relatively high crystalline component and the high molecular weight component, the low crystalline component and the low molecular weight component are inevitably increased, and as a result, it is applied to the laminated sheet surface. This causes problems such as stickiness due to bleed out and poor appearance, and is not suitable for applications requiring transparency. Moreover, since the increase in the high crystal component deteriorates the low-temperature heat-sealing property, the bag-making property cannot be obtained and this is also not suitable.

By adding a specific amount of component (I) to component (G) having a small amount of high crystal component and high molecular weight component, the amount of high crystal component and high molecular weight component is increased without increasing the amount of low crystal component and low molecular weight component. As a result, it is possible to suppress appearance defects such as thickness fluctuation and interface roughness without causing appearance defects such as bleed out. Moreover, the addition of a specific amount of a high crystalline component makes it easier to adjust the balance between heat resistance and low temperature heat sealability that suppresses inner surface fusion than expanding the crystallinity distribution.
Therefore, the component (I) is not particularly limited as long as it is a propylene resin satisfying the following condition (I-i), but is preferably a propylene-based (co) polymer component (I1) and a propylene-ethylene random copolymer. It is a propylene resin made of the polymer (I2).

(Ii) Melting peak temperature Tm (I)
The melting peak temperature Tm (I) of the propylene-based resin (I) needs to be 6 ° C. or more higher than the melting peak temperature Tm (G1) of the propylene-α-olefin random copolymer component (G1). By making the melting peak temperature 6 ° C. or more higher than the component (G1), the resulting multilayer sheet can be given a function of suppressing thinning during heat sealing without causing appearance defects such as bleed out. . More preferably, Tm (I) is higher than Tm (G1) by 10 ° C. or more, particularly 20 ° C. or more.

Component (I) is a propylene-based resin composition having a melting peak temperature Tm (I) preferably in the range of 150 to 165 ° C, more preferably 155 to 165 ° C.
When Tm (I) is less than 150 ° C., the high crystal component is insufficient and sufficient heat resistance cannot be imparted. Those having a Tm (I) exceeding 165 ° C. are difficult to produce industrially.

The propylene-based resin component (I) comprising the propylene-based (co) polymer component (I1) and the propylene-ethylene random copolymer (I2) is a propylene-based (co) polymer that satisfies the following condition (I1-i) It is preferably a propylene-based resin composed of a propylene-ethylene random copolymer (I2) that satisfies the conditions of the component (I1) and the following (I2-i), and in addition, a propylene-based resin that satisfies the following conditions (I-ii) Resin (I) is preferred.

  Here, the component (I1) is a polypropylene component and is a highly crystalline component. Component (I1) (hereinafter also referred to as component (I1)) has a melting peak temperature higher than that of component (G), and at a temperature at which component (G) melts and starts melt flow, the crystalline state ( Since it is in a solid state and has an action of suppressing the melt flow of the component (G), it is an effective component for suppressing inner surface fusion in a heating process such as sterilization. Therefore, the component (I1) needs to be a polypropylene or a propylene-ethylene copolymer made of a copolymer having higher crystallinity than the component (G). However, the addition of component (I1) increases the crystallinity of the entire intermediate layer, resulting in a loss of flexibility. Therefore, the addition of the component (I2) (hereinafter also referred to as component (I2)), which is a propylene-ethylene random copolymer and is a low crystalline component, imparts flexibility to the entire laminated sheet. It is effective for flexibility. The component (H) is also added to obtain the same effect. However, if the amount of the component (H) is too large, the moldability deteriorates, it is difficult to obtain a sheet having a uniform thickness, and the addition amount has an upper limit. Addition of component (I2) is effective when component (H) alone cannot fully compensate for flexibility. That is, the component (I2) is an effective component for suppressing the increase in rigidity due to the addition of the component (I1), which is a highly crystalline component.

(I1-i) Ratio of component (I1) and component (I2) in component (I) Component (I) is a component ratio of propylene-based (co) polymer component (I1) (hereinafter referred to as W (I1)) May be a mixture of 40 to 70 wt% and an ethylene-propylene copolymer component (I2) component ratio (hereinafter also referred to as W (I2)) of 30 to 60 wt%. However, those obtained by multistage polymerization are preferable in that the component (I2) is uniformly and finely dispersed.
Since the component (I2) is a low crystalline component, if there is too much W (I2), it is difficult to obtain a heat resistance reinforcing effect, and if there is too little W (I2), it is difficult to obtain a flexible reinforcing effect. Here, W (I1) and W (I2) can be obtained from the material balance.

(I2-i) Ethylene content (E (I2))
Component (I2) is a flexibility-imparting component necessary to minimize the increase in rigidity due to the addition of component (I1), which is a highly crystalline component. Therefore, since the component (I2) is controlled by the ethylene content (hereinafter sometimes referred to as E (I2)), the ethylene content is preferably 15 to 40 wt%.
If the ethylene content is less than 15 wt%, it is in a region compatible with propylene, so that it is difficult to obtain a sufficient flexibility imparting effect when added in a small amount. If the ethylene content exceeds 40 wt%, the ethylene content Too much and the transparency of the entire intermediate layer tends to deteriorate.
Here, E (I2) is a value obtained by the ¹³ C-NMR spectrum method described above.

(I-ii) Intrinsic viscosity ratio of component (I1) and component (I2) in component (I) Intrinsic viscosity [η] I2 (component (I2) in component (I) measured in 135 ° C. tetralin) Hereinafter, [η] I2 may also be 1.7 to 6.5 dl / g, preferably 1.7 to 4.0 dl / g, and the component (I1) measured under the same conditions. The intrinsic viscosity ratio [η] I2 / [η] I1 with the intrinsic viscosity [η] I1 (hereinafter sometimes referred to as [η] I1) is 0.6 to 1.2, particularly 0.6 to 1. A range of 1 is preferable.
[Η] I1 particularly affects processing characteristics such as sheet formability, and [η] I2 / [η] I1 affects dispersibility of the component (I2) into the component (I1). When [η] I1 is too large, the formability of the sheet is deteriorated, which causes a problem in production. On the other hand, if [η] I2 is too small, sufficient flexibility cannot be obtained, and if [η] I2 is too large, the transparency is deteriorated.

When component (I1) and component (I2) are continuously produced to obtain component (I), [η] I2 in component (I) cannot be directly measured, and thus [η] I1 can be directly measured. And the intrinsic viscosity [η] I of component (I) (hereinafter also referred to as [η] I) and W (I2), and the following formula.
[Η] I2 =
{[Η] I- (1-W (I2) / 100) [η] I1} / (W (I2) / 100)
Here, continuously producing means that the component (I1) is produced in the first stage described later (first process), and then the component (I2) is produced continuously in the second stage (second process). Means.

In the propylene-based resin (I) used in the present invention, the weight ratio of W (I1) and W (I2) (W (I2) / W (I1)) and the intrinsic viscosity ratio ([η]) Product ([η] I2 / [η] I1) × (W (I1) / W (I2))) with I2 / [η] I1) is preferably 0.2 to 4.5, more preferably 0.8. It is desirable to be in the range of 6 to 4.0.
The product of the weight ratio and the intrinsic viscosity ratio indicates the dispersion state of the component (I2) dispersed in the component (I1), and being within the above range indicates that the domain of the component (I2) is molded. It is an indispensable condition to show a specific dispersion structure that sometimes exists in a state where the domain alone is stretched in the flow direction, or is connected to at least one other domain, and the value is within the above numerical range. When it exists, the transparency of a sheet | seat obtained and a softness | flexibility will become favorable.

Method for Producing Component (I) The propylene resin (I) used in the present invention may be produced by any method as long as the above properties are satisfied. Of course, the propylene (co) polymers produced separately are used. Propylene-based (co) polymer (I1) is produced using a mixing device of (I1) and propylene-ethylene random copolymer (I2), and subsequently in the presence of propylene-based (co) polymer (I1). Propylene-ethylene random copolymer (I2) may be produced, and propylene-based resin (I) may be produced continuously. Specifically, the production methods described in JP 2006-35516 A and JP 2001-172454 A can be exemplified.
In addition, component (I) can also be suitably selected from what is marketed, and can also be used. Commercially available products include Nippon Polypro's brand name Newcon, Mitsubishi Chemical's brand name Zelas. In these uses, a grade satisfying the melting peak temperature, MFR, and intrinsic viscosity ratio, which are the conditions of the present invention, may be appropriately selected.

Ratio of Component (I) in Component (Z) The ratio of component (I) in component (Z) needs to be in the range of 1 to 25 wt%.
Since the component (I1) constituting the component (I) has a melting peak temperature higher than that of the component (G), the component (G) is melted and fluidized by maintaining a crystalline state even at a temperature at which the component (G) melts. The component (I2) constituting the component (I) has the effect of imparting heat resistance that suppresses the occurrence of flexibility, and the flexibility to minimize the increase in rigidity due to the addition of the component (I1), which is a highly crystalline component It has a grant effect.
At this time, if the amount of the component (I) is too small, the highly crystalline component is insufficient, and a sufficient heat resistance imparting effect cannot be obtained. Therefore, the amount must be 1 wt% or more, preferably 5 wt%. % Or more. On the other hand, if the amount of component (I) is too large, physical properties such as flexibility and transparency deteriorate significantly, and the quality required for the resin composition of the present invention cannot be satisfied. It is necessary to be below, preferably 20 wt% or less.

4). Other ingredients (additives)
The propylene resin compositions (X), (Y) and (Z) used for the intermediate layer (1), the outer layer (2) and the inner layer (3) in the propylene resin multilayer sheet of the present invention are suitable as a multilayer sheet. Therefore, any additive can be blended within a range that does not significantly impair the effects of the present invention, such as bleeding out. Examples of such optional components include antioxidants, crystal nucleating agents, clearing agents, lubricants, antiblocking agents, antistatic agents, antifogging agents, neutralizing agents, and metal inertness used in ordinary polyolefin resin materials. Examples thereof include an agent, a colorant, a dispersant, a peroxide, a filler, and a fluorescent brightening agent. Furthermore, an elastomer can be mix | blended as a component which provides a softness | flexibility in the range which does not impair the effect of this invention remarkably.
Various additive components are described in detail below.

(1) Antioxidants As antioxidants, specific examples of phenolic antioxidants include tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 1,1,3- Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, pentaerythrityl-tetrakis {3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate}, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10- Examples thereof include tetraoxaspiro [5,5] undecane, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid and the like.

Specific examples of phosphorus antioxidants include tris (mixed, mono and dinonylphenyl phosphite), tris (2,4-di-t-butylphenyl) phosphite, 4,4′-butylidenebis (3- Methyl-6-tert-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2-methyl-4-di-tridecylphosphite-5-tert-butylphenyl) butane, bis (2, 4-di-t-butylphenyl) pentaerythritol-di-phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t -Butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phos You can list s fights.
Specific examples of the sulfur-based antioxidant include di-stearyl-thio-di-propionate, di-myristyl-thio-di-propionate, pentaerythritol-tetrakis- (3-lauryl-thio-propionate), and the like. it can.
These antioxidants can be used singly or in combination of two or more as long as the effects of the present object are not impaired.

  The blending amount of the antioxidant is 0.01 to 1.0 part by weight, preferably 0.02 to 0.5 part by weight, and more preferably 0.05 to 0.1 part by weight with respect to 100 parts by weight of each resin. If the amount and the blending amount are less than the above ranges, the effect of thermal stability cannot be obtained, deterioration occurs during the production of the resin, and it becomes burned and causes fish eyes. On the other hand, when the above range is exceeded, it becomes a foreign substance and causes fish eyes, which is not preferable.

(2) Antiblocking agent As the antiblocking agent, those having an average particle diameter of usually 1 to 7 μm, preferably 1 to 5 μm, and more preferably 1 to 4 μm are used. If the average particle diameter is less than 1 μm, the slipperiness and openability of the resulting sheet are inferior, which is not preferable. On the other hand, if it exceeds 7 μm, the transparency and scratching property are remarkably inferior. Here, the average particle diameter is a value obtained by Coulter counter measurement.

Specific examples of the anti-blocking agent include, for example, inorganic or synthetic silica (silicon dioxide), magnesium silicate, aluminosilicate, talc, zeolite, aluminum borate, calcium carbonate, calcium sulfate, barium sulfate, and phosphoric acid. Calcium is used.
Also, as organic materials, polymethyl methacrylate, polymethylsilyl sesquioxane (silicone), polyamide, polytetrafluoroethylene, epoxy resin, polyester resin, benzoguanamine / formaldehyde (urea resin), phenol resin, etc. should be used. Can do.
In particular, synthetic silica and polymethyl methacrylate are preferable from the balance of dispersibility, transparency, blocking resistance, and scratch resistance.

The anti-blocking agent may be surface-treated, and as the surface treating agent, surfactant, metal soap, acrylic acid, oxalic acid, citric acid, tartaric acid and other organic acids, higher alcohols, esters, Silicone, fluororesins, silane coupling agents, hexametaphosphate soda, pyrophosphate soda, tripolyphosphate soda, trimetaphosphate soda, etc. can be used, especially organic acid treatment, especially citric acid treatment Those are preferred. The treatment method is not particularly limited, and a known method such as surface spraying or dipping can be employed.
The anti-blocking agent may have any shape, and may have any shape such as a spherical shape, a square shape, a column shape, a needle shape, a plate shape, or an indefinite shape.
These anti-blocking agents can be used singly or in combination of two or more in a range that does not impair the effects of this object.

  When the antiblocking agent is blended, the blending amount is usually 0.01 to 1.0 part by weight, preferably 0.05 to 0.7 part by weight, more preferably 0.1 to 100 parts by weight of the resin. 0.5 parts by weight. When the blending amount is less than the above range, the anti-blocking property, slipping property, and opening property of the sheet are likely to be inferior. If the above range is exceeded, the transparency of the sheet is impaired, and the sheet itself becomes a foreign substance, which causes fish eyes.

(3) Slip agent Examples of the slip agent include monoamides, substituted amides, bisamides, and the like, which can be used alone or in combination of two or more.
Specific examples of monoamides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide and the like as saturated fatty acid monoamides.
Examples of the unsaturated fatty acid monoamide include oleic acid amide, erucic acid amide, ricinoleic acid amide and the like.
Specific examples of substituted amides include N-stearyl stearic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid amide Etc.

Specific examples of bisamides include, as saturated fatty acid bisamides, methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bis stearic acid amide, ethylene bisisostearic acid amide, ethylene bishydroxystearic acid amide, Ethylene bisbehenic acid amide, hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bishydroxy stearic acid amide, N, N'-distearyl adipic acid amide, N, N'-distearyl Sepacic acid amide and the like can be mentioned.
Examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sepasin acid amide and the like.
Examples of the aromatic bisamide include m-xylylene bis stearic acid amide and N, N′-distearylisophthalic acid amide.
Among these, oleic acid amide, erucic acid amide, and behenic acid amide are particularly preferably used among the fatty acid amides.

  As a compounding quantity in the case of mix | blending a slip agent, it is 0.01-1.0 weight part with respect to 100 weight part of resin, Preferably it is 0.05-0.7 weight part, More preferably, it is 0.1-0. .4 parts by weight. If it is less than the said range, opening property and slipperiness will become inferior easily. If the above range is exceeded, the slip agent will be excessively raised, bleeding on the sheet surface and the transparency will deteriorate.

(4) Nucleating agent Specific examples of the nucleating agent include sodium 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphate, talc, 1,3,2,4-di (p-methyl). Benzylidene) sorbitol-based compounds such as sorbitol, hydroxy-di (t-butylbenzoic acid) aluminum, 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphoric acid and aliphatic having 8 to 20 carbon atoms And a monocarboxylic acid lithium salt mixture (trade name NA-21, manufactured by ADEKA Corporation).
As a compounding quantity in the case of mix | blending the said nucleating agent, 0.0005-0.5 weight part with respect to 100 weight part of each resin, Preferably it is 0.001-0.1 weight part, More preferably, it is 0.00. 005 to 0.05 parts by weight. Below the above range, the effect as a nucleating agent cannot be obtained. Exceeding the above range is undesirable because it itself becomes a foreign substance and causes fish eyes.

Moreover, a high density polyethylene resin can be mentioned as a nucleating agent other than the above. The density of the high-density polyethylene resin is 0.94 to 0.98 g / cm ³ , preferably 0.95 to 0.97 g / cm ³ . If the density is out of this range, the effect of improving transparency cannot be obtained. The 190 degreeC melt flow rate (MFR) of a high density polyethylene resin is 5 g / 10min or more, Preferably it is 7-500 g / 10min, More preferably, it is 10-100 g / 10min. When the MFR is less than 5 g / 10 min, the dispersion diameter of the high-density polyethylene resin is not sufficiently small, and it itself becomes a foreign matter and causes fish eyes. In order to finely disperse the high-density polyethylene resin, the MFR of the high-density polyethylene resin is preferably larger than the MFR of the propylene-based resin of the present invention.

  When used as a nucleating agent, the blending amount of the high-density polyethylene is 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, more preferably 0.1 to 1 part with respect to 100 parts by weight of the resin. Parts by weight. Below the above range, the effect as a nucleating agent cannot be obtained. Exceeding the above range is undesirable because it itself becomes a foreign substance and causes fish eyes.

(5) Neutralizing agent Specific examples of the neutralizing agent include calcium stearate, zinc stearate, hydrotalcite, Mizukarak (trade name, manufactured by Mizusawa Chemical Co., Ltd.), and the like.
When the neutralizing agent is blended, the blending amount is 0.01 to 1.0 part by weight, preferably 0.02 to 0.5 part by weight, more preferably 0.05 to 0.00 part by weight based on 100 parts by weight of the resin. 1 part by weight. If the blending amount is less than the above range, the effect as a neutralizing agent cannot be obtained, and the deteriorated resin inside the extruder is scraped off, causing fish eyes. On the other hand, when the above range is exceeded, it becomes a foreign substance and causes fish eyes, which is not preferable.

(6) Light Stabilizer As the light stabilizer, a hindered amine stabilizer is preferably used, and a structure in which all hydrogen bonded to carbons at the 2-position and 6-position of a conventionally known piperidine is substituted with a methyl group. Although the compound which has this is used without being specifically limited, the following compounds are specifically used preferably.

Specific examples include polycondensates of dimethyl oxalate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, tetrakis (1,2,2,6,6). -Pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, N, N-bis (3-aminopropyl) ) Ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4- Jil} {(2,2, , 6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,6-tetramethyl-4-piperidyl} imino], poly [(6-morpholino-s-triazine-2,4-diyl) And [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}].
These hindered amine stabilizers can be used singly or in combination of two or more in a range not impairing the effect of the present object.

When the hindered amine stabilizer is blended, the blending amount is 0.005 to 2 parts by weight, preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.5 parts by weight, based on 100 parts by weight of the resin. Is desirable.
When the content of the hindered amine stabilizer is less than 0.005 parts by weight, there is no effect of improving the stability such as heat resistance and aging resistance, and when it exceeds 2 parts by weight, the fish eye itself becomes a foreign substance. This is not preferable.

(7) Antistatic agent The antistatic agent can be used without particular limitation as long as it is a known antistatic agent or antistatic agent conventionally used, and examples thereof include anionic surfactants and cations. Ionic surfactants, nonionic surfactants, amphoteric surfactants and the like.

  Examples of the anionic surfactant include fatty acid or rosin acid soap, N-acyl carboxylate, ether carboxylate, carboxylate such as fatty acid amine salt; sulfosuccinate, ester sulfonate, N-acyl sulfonate Sulfonates such as salts; sulfated oils, sulfate esters, alkyl sulfate salts, sulfate sulfate polyoxyethylene salts, sulfate ether salts, sulfate ester salts such as sulfate amide salts; alkyl phosphate salts, alkyl polyoxyethylene phosphates Examples thereof include phosphoric ester salts such as salts, phosphoric acid ether salts and phosphoric acid amide salts.

  Examples of the cationic surfactant include amine salts such as alkylamine salts; alkyltrimethylammonium chloride, alkylbenzyldimethylammonium chloride, alkyldihydroxyethylmethylammonium chloride, dialkyldimethylammonium chloride, tetraalkylammonium salt, N, N-di Quaternary ammonium salts such as (polyoxyethylene) dialkylammonium salts and N-alkylalkanamide ammonium salts; 1-hydroxyethyl-2-alkyl-2-imidazoline, 1-hydroxyethyl-1-alkyl-2-alkyl Examples include alkyl imidazoline derivatives such as -2-imidazoline; imidazolinium salts, pyridinium salts, isoquinolinium salts, and the like.

  Examples of the nonionic surfactant include ether forms such as alkyl polyoxyethylene ether and p-alkylphenyl polyoxyethylene ether; fatty acid sorbitan polyoxyethylene ether, fatty acid sorbitol polyoxyethylene ether, fatty acid glycerin polyoxyethylene ether, etc. Ether ester form of fatty acid polyoxyethylene ester, monoglyceride, diglyceride, sorbitan ester, sucrose ester, dihydric alcohol ester, boric acid ester, etc .; dialcohol alkylamine, dialcohol alkylamine ester, fatty acid alkanolamide, N, N-di (polyoxyethylene) alkanamide, alkanolamine ester, N, N-di (polyoxyethylene) alkaneamine, amine oxy De, and the like as nitrogen and fabricated such as an alkyl polyethylene imine.

  Examples of the amphoteric surfactant include amino acid forms such as monoaminocarboxylic acid and polyaminocarboxylic acid; N-alkyl-β-alanine such as N-alkylaminopropionate and N, N-di (carboxyethyl) alkylamine salt. Forms: Betaine forms such as N-alkylbetaines, N-alkylamidobetaines, N-alkylsulfobetaines, N, N-di (polyoxyethylene) alkylbetaines, imidazolinium betaines; 1-carboxymethyl-1-hydroxy- And alkyl imidazoline derivatives such as 1-hydroxyethyl-2-alkyl-2-imidazoline and 1-sulfoethyl-2-alkyl-2-imidazoline.

  Among these, nonionic surfactants and amphoteric surfactants are preferable. Among them, monoglycerides, diglycerides, boric acid esters, dialcohol alkylamines, dialcohol alkylamine esters, amides and the like or nitrogen-containing non-type surfactants are preferred. Ionic surfactants; betaine amphoteric surfactants are preferred.

  In addition, as an antistatic agent, a commercial item can be used, for example, electro stripper TS5 (trade name, glycerin monostearate manufactured by Kao Corporation), electro stripper TS6 (trade name, stearyl manufactured by Kao Corporation). Diethanolamine), electrostripper EA (trade name, lauryl diethanolamine, manufactured by Kao Corporation), electrostripper EA-7 (trade name, polyoxyethylene laurylamine capryl ester, manufactured by Kao Corporation), Denon 331P (maruhishi oil ( Co., Ltd., trademark, stearyl diethanolamine monostearate), Denon 310 (manufactured by Maruhishi Oil Chemical Co., Ltd., trademark, alkyldiethanolamine fatty acid monoester), Register PE-139 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trademark) , Stearic acid mono & diglyceride Ester), Chemistat 4700 (Sanyo Chemical Industries Co., Ltd., trademark, alkyl dimethyl betaine), rheostat S (Lion Co., Ltd., trademark, alkyl diethanolamide), and the like.

  The blending amount when blending the antistatic agent is 0.01 to 2 parts by weight, preferably 0.05 to 1 part by weight, more preferably 0.1 to 0.8 parts by weight, based on 100 parts by weight of the resin. Most preferably, it is 0.2-0.5 weight part. These antistatic agents can be used singly or in combination of two or more in a range that does not impair the effects of this object. When the blending amount of the antistatic agent is less than 0.01 parts by weight, it is not possible to reduce the surface specific resistance and prevent the failure due to charging. When the amount is more than 2 parts by weight, powder blowing tends to occur on the sheet surface due to bleeding.

(8) Elastomer Preferred examples of the elastomer include a styrene elastomer, and a block or random copolymer of styrene and ethylene, propylene, 1-butene, butadiene, or isoprene, or a hydrogenated product thereof is preferable. Can be exemplified by Kuraray's trade name Hybra, JSR's trade name Dynalon, and the like.

[II] Production of each layer-constituting resin composition of propylene-based resin multilayer sheet The propylene-based resin composition (X) constituting the intermediate layer (1) in the propylene-based resin multilayer sheet of the present invention is the propylene-based resin composition ( A), an ethylene-α-olefin copolymer (B), optionally a propylene resin (C), and optionally other additives after mixing with a Henschel mixer, V blender, ribbon blender, tumbler blender, etc. It can be obtained by a kneading method using a kneader such as a single-screw extruder, a multi-screw extruder, a kneader, or a Banbury mixer.

  The propylene-based resin composition (Y) constituting the outer layer (2) in the propylene-based resin multilayer sheet of the present invention includes the above-described propylene-based resin (D) and, if necessary, other additives, a Henschel mixer, a V blender. After mixing with a ribbon blender, a tumbler blender or the like, it is obtained by a method of kneading with a kneader such as a single screw extruder, a multi-screw extruder, a kneader or a Banbury mixer.

The propylene-based resin composition (Z) constituting the inner layer (3) in the propylene-based resin multilayer sheet of the present invention includes the propylene-based resin composition (G), the ethylene-α-olefin copolymer (H), and the propylene-based resin. After mixing other additives with the propylene resin composition (Z) with the resin (I), if necessary, using a Henschel mixer, V blender, ribbon blender, tumbler blender, etc., single screw extruder, multi screw extruder And kneading with a kneader such as a kneader or a Banbury mixer.
Moreover, each component of each resin composition described above may be mixed at the same time, or may be mixed and kneaded after making a part as a master batch.

[III] Propylene resin multilayer sheet The propylene resin multilayer sheet of the present invention can be produced by a known method using the propylene resin composition. For example, it is manufactured by a known technique such as extrusion using a T die or a circular die.
The propylene-based resin multilayer sheet of the present invention is excellent in flexibility, transparency, impact resistance, heat resistance, cleanliness, can suppress deterioration in transparency due to poor appearance such as uneven thickness, rough interface, and heat seal etc. Heat treatment packaging bags that require heat treatment processes such as sterilization and sterilization, because thinning can be suppressed in the secondary processing of the above, so that mechanical strength is maintained and productivity is improved because of excellent low-temperature heat sealability. In particular, it is suitable for infusion bags and the like.

  The propylene-based resin multilayer sheet of the present invention is characterized by having excellent flexibility even after heat treatment, and it is desirable that the tensile elastic modulus, which is a measure of flexibility, is 330 MPa or less. When the tensile elastic modulus is 300 MPa or less, preferably 280 MPa or less, the feeling of stiffness is lost, so that the tactile feeling is good and a high-class feeling can be produced.

  The propylene-based resin multilayer sheet of the present invention has excellent transparency, and a haze as a measure of transparency is 20% or less, preferably 18% or less, preferably 15% or less after heat treatment. In this case, the contents can be clearly shown, and it is very excellent in that it is possible to confirm whether or not there are foreign objects in the contents.

  The propylene-based resin multilayer sheet of the present invention is excellent in impact resistance, particularly impact resistance at a low temperature of 0 to 5 ° C., and dropped from a height of 100 cm in a low temperature drop test that is a measure of low temperature impact resistance. It has excellent impact resistance that it does not break, and it is excellent in that it can be used as a product without being broken even if it is dropped in the transportation process or storage process. Preferably, the bag does not break even if dropped from 150 cm, and more preferably it does not break even if dropped from 200 cm.

  In addition, the propylene-based resin multilayer sheet of the present invention has excellent heat resistance, and has excellent heat resistance that does not cause deformation and inner surface fusion even when heat treatment at about 121 ° C. is performed. . The deformed one has a poor appearance and the product value is lowered, and the one fused on the inner surface cannot be used as a product because it may hinder the discharge when the contents are discharged.

  Moreover, the propylene-based resin multilayer sheet of the present invention has excellent cleanliness, and there are very few low molecular weight components and low regularity components that may contaminate the contents in the inner layer (3) in contact with the contents. It is desirable to use a propylene-based resin composition obtained using a metallocene catalyst.

Furthermore, the propylene-based resin multilayer sheet of the present invention is excellent in that it has excellent low-temperature heat sealing properties and can improve productivity. Excellent heat at a heat seal pressure of 3.4 gf / cm ² and a heat seal time of 5 seconds at a heat seal strength of 3,000 gf / 10 mm or higher, a heat seal temperature of 145 ° C. or lower, more preferably 140 ° C. or lower. Has sealing properties.

  In the following, in order to describe the present invention more specifically and clearly, the present invention will be described in contrast to Examples and Comparative Examples to demonstrate the rationality and significance of the constituent elements of the present invention. The invention is not limited to these examples. The physical property measurement methods, characteristic evaluation methods, and resin materials used in Examples and Comparative Examples are as follows.

1. Method for measuring resin physical properties (1) MFR: propylene resin composition (A), propylene resin (C), propylene resin (D), propylene resin composition (G), propylene resin (I) According to JIS K7210 A method condition M, test temperature: 230 ° C., nominal load: 2.16 kg, die shape: diameter 2.095 mm, length 8.00 mm.
The ethylene-α-olefin copolymer (B) and the ethylene-α-olefin copolymer (H) are in accordance with JIS K7210 A method condition D, test temperature: 190 ° C., nominal load: 2.16 kg, die shape: diameter. It was measured at 2.095 mm length 8.00 mm.
(2) Density: The density was measured by the density gradient tube method based on the JIS K7112 D method using the extruded strand obtained at the time of MFR measurement.
(3) Melting peak temperature: Using a Seiko DSC, take 5.0 mg of sample, hold at 200 ° C. for 5 minutes, crystallize to 40 ° C. at a rate of 10 ° C./min, and further 10 ° C./min. The melting peak temperature when melted at a rate of temperature rise of was measured.

(4) Measurement of solid viscoelasticity A sample cut into a strip of 10 mm width × 18 mm length × 2 mm thickness from a 2 mm thick sheet injection-molded under the following conditions was used. The apparatus used was ARES manufactured by Rheometric Scientific. The frequency is 1 Hz. The measurement temperature was raised stepwise from −60 ° C., and the measurement was performed until the sample melted and became impossible to measure. The strain was performed in the range of 0.1 to 0.5%.
[Preparation of specimen]
Standard number: JIS-7152 (ISO294-1)
Molding machine: Toshiba Machine EC-20 injection molding machine Setting temperature: 80, 80, 160, 200, 200, 200 ° C from below the hopper
Mold temperature: 40 ℃
Injection speed: 200 mm / sec (speed in the mold cavity)
Holding pressure: 20 MPa
Holding time: 40 seconds Mold shape: Flat plate (thickness 2 mm, width 40 mm, length 80 mm)

(5) 0 ° C. soluble content (S0) of the propylene-based resin composition (Z):
Measurement was performed by the method described above.

2. Evaluation method of propylene-based resin multilayer sheet (1) Heat resistance (appearance)
A cylindrical propylene-based resin multilayer sheet is cut into a size of 210 mm in the flow direction, and one of the cut out pieces is heat sealed (heat sealing condition: pressure 3.4 kgf / cm ² , time 5 seconds, temperature 160 ° C., tester A heat sealer manufactured by Sangyo Co., Ltd. was used to form a bag. Next, 500 ml of pure water was filled therein, and the other side was heat sealed using an impulse sealer and sealed. Sealing was performed such that the distance between the heat seal and the heat seal was 200 mm.

The sample bag thus obtained was put into a high-temperature and high-pressure cooking sterilization tester (manufactured by Nisaka Manufacturing Co., Ltd., RCS-40RTGN type) and then pressurized, and the ambient temperature was increased to 121 ° C. For 30 minutes. Then, it cooled to about 40 degreeC and took out this sample bag from the testing machine. (Hereinafter, the sterilized multilayer sheet (sample bag) may be referred to as “heat-treated multilayer sheet”).
The heat resistance evaluation of the multilayer sheet after the heat treatment was performed according to the following criteria.
Δ: Deformation, wrinkle, inner surface fusion occurred and cannot be used.
○-: Slightly deformed but usable level.
○: Deformation, wrinkling, and inner surface fusion are not caused, and it is in a good state.

(2) Transparency (HAZE)
Based on JIS K7136-2000, the transparency of the laminated sheet after heat treatment was measured with a haze meter. The smaller the value obtained, the better the transparency, and when this value is 20% or less, it is easy to confirm the contents and the display effect is excellent, and 18% or less is preferable, and 15% or less. Is particularly preferred.

(3) Flexibility (tensile modulus)
Based on JIS K-7127-1989, the tensile elasticity modulus about the flow direction (MD) of the laminated sheet after heat processing was measured on condition of the following. It means that the smaller the obtained value is, the better the flexibility is, and when this value is 330 MPa or less, it is excellent in terms of obtaining a high-quality feeling with a good touch feeling, preferably 300 MPa or less, particularly preferably 280 MPa or less. preferable.
Sample length: 150mm
Sample width: 15mm
Distance between chucks: 100mm
Crosshead speed: 1mm / min

(4) Low temperature impact resistance (cumulative falling bag test)
After heat treatment with water filled, the multilayer sheets (2 pieces) were conditioned at 4 ° C for 48 hours, then dropped twice from 50cm onto the iron plate at that temperature, and dropped from 100cm twice if not broken, If the bag was not broken, it was dropped from 150 cm twice, and if it was not broken, it was dropped from 200 cm twice. It is desirable that the bag does not break even if dropped from 100 cm. Preferably, the bag does not break even if dropped from 150 cm. More preferably, the bag does not break even if dropped from 200 cm. In addition, the thing which did not break a bag was set as (circle), and the thing which broke the bag was set as x.

(5) Easy bag making (low temperature heat sealability: heat seal strength)
A cylindrical propylene-based resin multilayer sheet is cut into a size of 100 mm in the flow direction, and one of the cut out pieces is heat sealed (heat sealing condition: pressure 3.4 kgf / cm ² , time 5 seconds, temperature 125 to 160 ° C. Was made into a bag shape and conditioned for 24 hours in an atmosphere of 23 ° C. and 50% RH. Next, 500 ml of pure water was filled therein, and the other side was heat sealed using an impulse sealer and sealed.
The sample bag thus obtained was put into a high-temperature and high-pressure cooking sterilization tester (manufactured by Nisaka Manufacturing Co., Ltd., RCS-40RTGN type) and then pressurized, and the ambient temperature was increased to 121 ° C. For 30 minutes. Then, it cooled to about 40 degreeC and took out this sample bag from the testing machine. Thereafter, the water is drained, the heat-sealed portion is cut into a strip of 10 mm width, a peeling test is performed at a peeling speed of 500 mm / min using a universal testing machine (Tensilon universal testing machine, manufactured by Orientec Co., Ltd.), and a laminated sheet The heat seal strength of was determined.
The higher the obtained numerical value, the stronger the heat-sealing between the laminated sheets. When this numerical value is 3,000 gf / 10 mm or more, the laminated sheet can be sufficiently used.
Further, the lower the heat seal temperature at which a heat seal strength of 3,000 gf / 10 mm or more can be maintained, the more the productivity is improved and the bag-making ability is excellent. Preferably it is 145 degrees C or less, More preferably, it is 140 degrees C.

3. Resin used (1) Propylene resin composition for intermediate layer (A)
(1-1) Propylene-based resin composition for intermediate layer by blending (A)
As propylene-α-olefin random copolymer (A1), propylene-α-olefin random copolymers (A1-1) to (A1-7) of the following <A1> are converted into propylene-ethylene random copolymers (A2). ), The following <A2> propylene-ethylene random copolymers (A2-1) to (A2-4) were used.

<A1>
A1-1: Commercial product Product name “WINTEC WFW4” manufactured by Nippon Polypro Co., Ltd.
(Propylene-ethylene random copolymer with metallocene catalyst)
A1-2: Produced according to the following Production Example A1-2.
AI-3: Commercial product Nippon Polypro's product name “NOVATEC PP FW4B”
(Propylene-α-olefin copolymer with Ziegler-Natta catalyst)
A1-4: Commercial product Nippon Polypro's product name “NOVATEC PP EG7F”
(Propylene-ethylene random copolymer with Ziegler-Natta catalyst)
A1-5: Commercially available product “VERSIFY3000” manufactured by Dow Chemical Co., Ltd.
(Propylene-ethylene random copolymer with metallocene catalyst)
A1-6: Produced according to the following Production Example A1-6.
A1-7: Commercial product “NOVATEC PP SA06A” manufactured by Nippon Polypro Co., Ltd.
(Propylene homopolymer with Ziegler-Natta catalyst)

<A2>
A2-1: Commercial product Product name “VISTAMAX3000” manufactured by ExxonMobil Chemical Co. (propylene-ethylene random copolymer with metallocene catalyst)
A2-2: Commercially available product “VERSIFY3000” manufactured by Dow Chemical Company
(Propylene-ethylene random copolymer with metallocene catalyst)
A2-3: Commercially available product “ADFLEX X100G” manufactured by Lion Del Basel
(Propylene-ethylene random copolymer with Ziegler-Natta catalyst)
A2-4: Commercially available product “VISTAMAXX2120” manufactured by ExxonMobil Chemical Co. (propylene-ethylene random copolymer with metallocene catalyst)

(Production Example A1-2)
(I) Synthesis of transition metal compound The synthesis of [(r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] zirconium] It carried out according to the Example as described in -226712 gazette.
(Ii) Chemical treatment of silicate To a glass separable flask equipped with a 10 liter stirring blade, 3.75 liters of distilled water and then 2.5 kg of concentrated sulfuric acid (96%) were slowly added. At 50 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle size = 25 μm, particle size distribution = 10 μm to 60 μm) was further dispersed, heated to 90 ° C., and maintained at that temperature for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake, and after reslurry, it was filtered. This washing operation was performed until the pH of the washing liquid (filtrate) exceeded 3.5.
The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 707 g.

(Iii) Drying of silicate The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: cylindrical, inner diameter 50 mm, heating zone 550 mm (electric furnace), rotation speed with lifting blade: 2 rpm, tilt angle: 20/520, silicate feed rate: 2.5 g / min, gas flow rate: nitrogen, 96 liters / hour, countercurrent, drying temperature: 200 ° C. (powder temperature)
(Iv) Preparation of catalyst 20 g of the dry silicate obtained as described above was introduced into a glass reactor equipped with a stirring blade having an internal volume of 1 liter, and 116 ml of mixed heptane and further a heptane solution of triethylaluminum (0. 60M) 84 ml was added and stirred at room temperature. After 1 hour, the mixture was washed with mixed heptane to prepare a silicate slurry to 200 ml.
Next, 0.96 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added to the silicate slurry prepared as described above and reacted at 25 ° C. for 1 hour. In parallel, 218 mg (0.3 mmol) of [(r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] zirconium] and mixed heptane To 87 ml, 3.31 ml of triisobutylaluminum heptane solution (0.71 M) was added, and the mixture reacted at room temperature for 1 hour was added to the silicate slurry. After stirring for 1 hour, 500 ml of mixed heptane was added. Prepared.

(V) Prepolymerization / Washing Subsequently, the previously prepared silicate / metallocene complex slurry was introduced into a stirring autoclave having an internal volume of 1.0 liter sufficiently substituted with nitrogen. When the temperature was stabilized at 40 ° C., propylene was supplied at a rate of 10 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours.
After completion of the prepolymerization, the residual monomer was purged, stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then the supernatant was decanted by 240 ml. Subsequently, 0.95 ml of a heptane solution of triisobutylaluminum (0.71 M / L) and 560 ml of mixed heptane were further added, stirred at 40 ° C. for 30 minutes, allowed to stand for 10 minutes, and then 560 ml of the supernatant was removed. This operation was further repeated 3 times. When the component analysis of the final supernatant was performed, the concentration of the organoaluminum component was 1.23 mmol / liter, the Zr concentration was 8.6 × 10 ⁻⁶ g / L, and the abundance in the supernatant relative to the charged amount was It was 0.016%.
Subsequently, 17.0 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added, followed by drying at 45 ° C. under reduced pressure. By this operation, a prepolymerized catalyst containing 2.0 g of polypropylene per 1 g of the solid catalyst component was obtained.

(Vi) Polymerization After the inside of a stirring autoclave having an internal volume of 200 liters was sufficiently substituted with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced. To this, 500 ml (0.12 mol) of a triisobutylaluminum / n-heptane solution, 0.32 kg of ethylene, and 2.5 liters of hydrogen (as a standard state volume) were added, and the internal temperature was maintained at 30 ° C. Subsequently, 1.90 g (as a solid catalyst component) of a metallocene polymerization catalyst was injected with argon to initiate polymerization, the temperature was raised to 70 ° C. over 40 minutes, and the temperature was maintained for 60 minutes. Here, 100 ml of ethanol was added to stop the reaction. The residual gas was purged to obtain 20.3 kg of a polypropylene polymer. This operation was repeated 5 times to obtain a propylene-ethylene random copolymer PP (A1-2).
The resin had an MFR of 7 g / 10 min, an ethylene content of 0.75 mol%, and a melting point of 142 ° C.

Production Example (A1-6)
(I) Production of Solid Component (A) A 10 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 2 L of purified n-heptane was introduced. Further, 250 g of MgCl ₂ and 1.8 L of Ti (On-Bu) ₄ were added, and a reaction was performed at 95 ° C. for 2 hours. The reaction product was cooled to 40 ° C. and 500 ml of methyl hydrogen polysiloxane (20 centistokes) was added. After 5 hours of reaction at 40 ° C., the precipitated solid product was thoroughly washed with purified n-heptane.
Subsequently, purified n-heptane was introduced to adjust the concentration of the solid product to 200 g / L. Here, 300 ml of SiCl ₄ was added and a reaction was carried out at 90 ° C. for 3 hours. The reaction product was thoroughly washed with purified n-heptane, and purified n-heptane was introduced so that the concentration of the reaction product was 100 g / L. A solution prepared by mixing 30 ml of phthalic dichloride with 270 ml of purified n-heptane was added thereto, and a reaction was performed at 90 ° C. for 1 hr. The reaction product was thoroughly washed with purified n-heptane, and purified n-heptane was introduced so that the concentration of the reaction product was 200 g / L. To this, 1 L of TiCl ₄ was added and a reaction was carried out at 95 ° C. for 3 hours. The reaction product was thoroughly washed with purified n-heptane to obtain a slurry of the solid component (A). A portion of this slurry was sampled and dried. As a result of analysis, the Ti content of the solid component (A) was 2.5 wt%.

(Ii) Preparation of Solid Catalyst Component (B) Next, a 20 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 100 g of the solid component (A) slurry was introduced as a solid component (A). Purified n-heptane was introduced to adjust the concentration of the solid component (A) to 20 g / L. Here, trimethyl vinyl silane 25 ml, was added 50g as (t-Bu) (Me) Si (OEt) 2 to 25 ml, _Et 3 Al of n- heptane dilution _Et 3 Al, were 2hr reaction at 30 ° C. . The reaction product was thoroughly washed with purified n-heptane, and a portion of the resulting slurry was sampled and dried. As a result of analysis, the solid component contained 2.1 wt% Ti and 6.1 wt% (t-Bu) (Me) Si (OEt) ₂ .
Prepolymerization was performed by the following procedure using the solid component obtained above. Purified n-heptane was introduced into the slurry, and the solid component concentration was adjusted to 10 g / L. After cooling the slurry to 10 ° C., and 10g added n- heptane dilution of _Et 3 Al as _Et 3 Al, were fed over 2hr of propylene 150 g. After the supply of propylene was completed, the reaction was further continued for 30 minutes. Next, the gas phase was sufficiently replaced with nitrogen, and the reaction product was thoroughly washed with purified n-heptane. The obtained slurry was extracted from the autoclave and vacuum dried to obtain a solid catalyst component (B). This solid catalyst component (B) contained 1.2 g of polypropylene per 1 g of the solid component. As a result of analysis, the solid catalyst component (B) excluding polypropylene contained 1.6 wt% Ti and 5.5 wt% (t-Bu) (Me) Si (OEt) ₂ .

(Iii) Polymerization The inside of a stirring autoclave having an internal volume of 200 L was sufficiently substituted with propylene, and 80 L of purified n-heptane was introduced. After the temperature was raised to 70 ° C., 1.5 g of n- heptane dilution of _Et 3 Al as _Et 3 Al, hydrogen 5.0NL, and the solid catalyst component (B) 0.25 g (provided that a prepolymerized polymer excluded) Was introduced. After raising the temperature to 75 ° C., propylene was supplied so that the pressure became 0.7 MPaG, and polymerization was started. During the polymerization, the supply of propylene was continued so as to maintain the pressure. After 3 hours, 1 L of butanol was added to terminate the polymerization. The remaining propylene was purged and fully replaced with nitrogen. The obtained slurry was filtered with a centrifugal separator and then dried with a dryer to obtain PP (A1-6).

Tables 3 and 4 below show the results of various analyzes of the PP (A1-1) to PP (A1-7) and PP (A2-1) to PP (A2-4).
PP (A1-1) to PP (A1-4) satisfy all the requirements of the present invention as a propylene-α-olefin random copolymer (A1). On the other hand, PP (A1-5) to PP (A1-7) do not satisfy the requirements of the present invention as the propylene-α-olefin random copolymer (A1).
PP (A2-1) and PP (A2-4) satisfy all the requirements of the present invention as a propylene-ethylene random copolymer (A2). On the other hand, PP (A2-3) to PP (A2-4) do not satisfy the requirements of the present invention as the propylene-ethylene random copolymer (A2).

  As the propylene-α-olefin random copolymer (A1), the propylene-α-olefin random copolymers (A1-1) to (A1-7) of the above <A1> and the propylene-ethylene random copolymer (A2) ), <A2> propylene-ethylene random copolymers (A2-1) to (A2-4) are weighed so as to have the composition ratios shown in Table 5 below, and stirred and mixed with a Henschel mixer. As a result, propylene resin compositions PP (A-1) to PP (A-16) were obtained.

Various analysis results of the composition are shown in Tables 5 and 6 below.
PP (A-1) to PP (A-6) satisfy all the requirements of the present invention as the propylene-α-olefin random copolymer (A1). On the other hand, PP (A-7) to PP (A-16) do not satisfy the requirements of the present invention as the propylene-based resin composition (A).

(2) Ethylene-α-olefin copolymer for intermediate layer (B)
Resins PE (B-1) to PE (B-6) obtained in the following production examples (B-1) to (B-6) and commercially available postscript PE (B-7) to PE (B-8) It was used.

(Production Example B-1)
A copolymer of ethylene and hexene-1 was prepared. The catalyst was prepared by the method described in JP-T-7-508545 (preparation of catalyst system). That is, to the complex dimethylsilylene bis (4,5,6,7-tetrahydroindenyl) hafnium dimethyl 2.0 mmol, tripentafluorophenyl boron was added in an equimolar amount to the above complex, and diluted to 10 liters with toluene. A catalyst solution was prepared.
A mixture of ethylene and 1-hexene was supplied to a stirred autoclave type continuous reactor having an internal volume of 1.5 liter so that the composition of 1-hexene was 73% by weight, and the pressure in the reactor was maintained at 130 MPa. The reaction was performed at 127 ° C. The polymer production per hour was about 2.5 kg.
After the reaction was completed, various analyzes of the obtained polymer were performed. Various analysis results of the obtained ethylene-α-olefin copolymer PE (B-1) are shown in Table 7.

(Production Examples B-2 to 6)
Catalyst preparation and polymerization were carried out in the same manner as in Production Example (B-1) except that the composition of 1-hexene and the polymerization temperature during polymerization were changed as shown in Table 7.
After the reaction was completed, various analyzes of the obtained polymer were performed.

The commercial products used are as follows.
B-7: Commercial product Nippon Polyethylene's trade name “KERNEL KF283”
(Ethylene-α-olefin copolymer by metallocene catalyst)
B-8: Commercial product, trade name “KERNEL KJ640T” manufactured by Nippon Polyethylene
(Ethylene-α olefin copolymer with metallocene catalyst)

Table 7 shows various analysis results of PE (B-1) to PE (B-8).
PE (B-1) to PE (B-6) satisfy all the requirements of the present invention as the component (B).
On the other hand, PE (B-7) and PE (B-8) do not satisfy the requirements of the present invention as the component (B).

(3) Propylene resin for intermediate layer (C)
Resins (PP (C-1) to PP (C-5) obtained in the following production examples (C-1) to (C-5) were used.PP (C-1) to PP (C-4) Is a homopolypropylene obtained by single-stage polymerization, and PP (C-5) is a block copolymerized polypropylene obtained by multistage polymerization.
The following commercially available polypropylene resins were used.
(C-6) Nippon Polypro's product name "WINTEC WFW4"
(Random polypropylene obtained by single-stage polymerization)
(C-7) Nippon Polypro's trade name “WINTEC WFX4”
(Random polypropylene obtained by single-stage polymerization)
(C-8) Nippon Polypro's product name "Novatec PP SA06A"
(Homopolypropylene obtained by single-stage polymerization)
The MFR and Tm are shown in Table 8.

(Production Example C-1)
(I) Production of Solid Component (A) A 10 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 2 L of purified n-heptane was introduced. Further, 250 g of MgCl ₂ and 1.8 L of Ti (On-Bu) ₄ were added, and a reaction was performed at 95 ° C. for 2 hours. The reaction product was cooled to 40 ° C. and 500 ml of methyl hydrogen polysiloxane (20 centistokes) was added. After 5 hours of reaction at 40 ° C., the precipitated solid product was thoroughly washed with purified n-heptane.
Subsequently, purified n-heptane was introduced to adjust the concentration of the solid product to 200 g / L. Here, 300 ml of SiCl ₄ was added and a reaction was carried out at 90 ° C. for 3 hours. The reaction product was thoroughly washed with purified n-heptane, and purified n-heptane was introduced so that the concentration of the reaction product was 100 g / L. A solution prepared by mixing 30 ml of phthalic dichloride with 270 ml of purified n-heptane was added thereto, and a reaction was performed at 90 ° C. for 1 hr. The reaction product was thoroughly washed with purified n-heptane, and purified n-heptane was introduced so that the concentration of the reaction product was 200 g / L. To this, 1 L of TiCl ₄ was added and a reaction was carried out at 95 ° C. for 3 hours. The reaction product was thoroughly washed with purified n-heptane to obtain a slurry of the solid component (A). A portion of this slurry was sampled and dried. As a result of analysis, the Ti content of the solid component (A) was 2.5 wt%.

(Ii) Preparation of Solid Catalyst Component (B) Next, a 20 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 100 g of the solid component (A) slurry was introduced as a solid component (A). Purified n-heptane was introduced to adjust the concentration of the solid component (A) to 20 g / L. Here, trimethyl vinyl silane 25 ml, was added 50g as (t-Bu) (Me) Si (OEt) 2 to 25 ml, _Et 3 Al of n- heptane dilution _Et 3 Al, were 2hr reaction at 30 ° C. . The reaction product was thoroughly washed with purified n-heptane, and a portion of the resulting slurry was sampled and dried. As a result of analysis, the solid component contained 2.1 wt% Ti and 6.1 wt% (t-Bu) (Me) Si (OEt) ₂ .
Prepolymerization was performed by the following procedure using the solid component obtained above. Purified n-heptane was introduced into the slurry, and the solid component concentration was adjusted to 10 g / L. After cooling the slurry to 10 ° C., and 10g added n- heptane dilution of _Et 3 Al as _Et 3 Al, were fed over 2hr of propylene 150 g. After the supply of propylene was completed, the reaction was further continued for 30 minutes. Next, the gas phase was sufficiently replaced with nitrogen, and the reaction product was thoroughly washed with purified n-heptane. The obtained slurry was extracted from the autoclave and vacuum dried to obtain a solid catalyst component (B). This solid catalyst component (B) contained 1.2 g of polypropylene per 1 g of the solid component. As a result of analysis, the solid catalyst component (B) excluding polypropylene contained 1.6 wt% Ti and 5.5 wt% (t-Bu) (Me) Si (OEt) ₂ .

(Iii) Polymerization The inside of a stirring autoclave having an internal volume of 200 L was sufficiently substituted with propylene, and 80 L of purified n-heptane was introduced. After the temperature was raised to 70 ° C., 1.5 g of n- heptane dilution of _Et 3 Al as _Et 3 Al, hydrogen 5.0NL, and the solid catalyst component (B) 0.25 g (provided that a prepolymerized polymer excluded) Was introduced. After raising the temperature to 75 ° C., propylene was supplied so that the pressure became 0.7 MPaG, and polymerization was started. During the polymerization, the supply of propylene was continued so as to maintain the pressure. After 3 hours, 1 L of butanol was added to terminate the polymerization. The remaining propylene was purged and fully replaced with nitrogen. The obtained slurry was filtered with a centrifugal separator and then dried with a dryer to obtain PP (C-1).

(Production Examples C-2 to C-4)
Except having changed the quantity of hydrogen used in superposition | polymerization, it implemented similarly to manufacture example C-1, and obtained PP (C-2) -PP (C-4). The results are shown in Table 8.

(Production Example C-5)
(I) Production of solid component catalyst 20 liters of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel with a stirrer having an internal volume of 50 liters purged with nitrogen, and then 4 moles of magnesium chloride and 8 moles of tetrabutoxytitanium were introduced. After reacting at 95 ° C. for 2 hours, the temperature was lowered to 40 ° C., 480 ml of methylhydropolysiloxane (20 centistokes) was added, and the mixture was further reacted for 3 hours. Was washed with n-heptane.
Subsequently, 15 l of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel equipped with a stirrer as described above, then 3 mol of solid component was added in terms of magnesium atom, and 8 mol of silicon tetrachloride was added to 25 ml of n-heptane. The added mixed solution was introduced at 30 ° C. over 30 minutes, the temperature was raised to 90 ° C., and the mixture was reacted for 1 hour. Then, the reaction solution was taken out, and the produced solid component was washed with n-heptane.

Further, 5 l of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel equipped with a stirrer as described above, and then 250 g of the titanium-containing solid component treated with silicon tetrachloride obtained above, 750 g of 1,5-hexadiene, t -Butyl-methyl-dimethoxysilane (130 ml), divinyldimethylsilane (10 ml) and triethylaluminum (225 g) were introduced and contacted at 30 ° C. for 2 hours. The reaction solution was taken out and washed with n-heptane to obtain a solid component catalyst. .
The obtained solid component catalyst had a prepolymerization amount of 1,5-hexadiene of 2.97 g per titanium-containing solid component.

(Ii) Propylene / propylene-ethylene two-stage polymerization Propylene and triethylaluminum and polymerization in a first-stage reactor having an internal volume of 550 l under pressure at a temperature of 70 ° C (about 3.2 MPa at 70 ° C) The solid component catalyst in an amount such that the production rate is 20 kg / hour is continuously supplied, and hydrogen is also continuously supplied as a molecular weight regulator, and the first stage polymerization is carried out in the liquid phase. did.
Subsequently, the produced polymer is introduced into a second-stage reactor having an internal volume of 1900 l via a propylene purge tank, and the composition ratio of the target copolymer is adjusted to a pressure of 3.0 MPa at a temperature of 60 ° C. Propylene and ethylene are continuously supplied according to the above, hydrogen is continuously supplied as a molecular weight regulator, and active hydrogen compound (ethanol) is supplied to the titanium atoms in the solid component catalyst supplied in the first stage. The polymer was fed in a 200-fold mole and 2.5-fold mole with respect to triethylaluminum, the polymerization was carried out in the gas phase, the product polymer was continuously transferred to a vessel, Nitrogen gas was introduced to stop the reaction (second stage polymerization).
Table 8 shows the analysis results of the obtained PP (C-5). The ethylene content in the propylene-ethylene copolymer was measured by the method described above.

  PP (C-1)-(C-5) satisfy | fills all the preferable requirements in this invention as propylene-type resin (C). On the other hand, PP (C-6) to (C-8) do not satisfy the preferable requirements of the present invention as the propylene-based resin (C).

(4) Propylene resin (D) for outer layer (2)
The following commercially available propylene-ethylene random copolymers and the resins obtained in the following production examples (D-2) to (D-4) were used. Table 9 shows MFR and Tm.
(D-1): Nippon Polypro's trade name “WINTEC WFW4”
(D-5): Nippon Polypro's trade name “WINTEC WFX4”
(D-2) to (D-3): Ziegler-Natta catalyst homopolypropylene produced by the following single-stage polymerization (D-4): Block copolymerized polypropylene produced by the following multistage polymerization

(Production Example D-2)
(I) Production of Solid Component (A) A 10 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 2 L of purified n-heptane was introduced. Further, 250 g of MgCl ₂ and 1.8 L of Ti (On-Bu) ₄ were added, and a reaction was performed at 95 ° C. for 2 hours. The reaction product was cooled to 40 ° C. and 500 ml of methyl hydrogen polysiloxane (20 centistokes) was added. After 5 hours of reaction at 40 ° C., the precipitated solid product was thoroughly washed with purified n-heptane.
Subsequently, purified n-heptane was introduced to adjust the concentration of the solid product to 200 g / L. Here, 300 ml of SiCl ₄ was added and a reaction was carried out at 90 ° C. for 3 hours. The reaction product was thoroughly washed with purified n-heptane, and purified n-heptane was introduced so that the concentration of the reaction product was 100 g / L. A solution prepared by mixing 30 ml of phthalic dichloride with 270 ml of purified n-heptane was added thereto, and a reaction was performed at 90 ° C. for 1 hr. The reaction product was thoroughly washed with purified n-heptane, and purified n-heptane was introduced so that the concentration of the reaction product was 200 g / L. To this, 1 L of TiCl ₄ was added and a reaction was carried out at 95 ° C. for 3 hours. The reaction product was thoroughly washed with purified n-heptane to obtain a slurry of the solid component (A). A portion of this slurry was sampled and dried. As a result of analysis, the Ti content of the solid component (A) was 2.5 wt%.

(Ii) Preparation of Solid Catalyst Component (B) Next, a 20 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 100 g of the solid component (A) slurry was introduced as a solid component (A). Purified n-heptane was introduced to adjust the concentration of the solid component (A) to 20 g / L. Here, trimethyl vinyl silane 25 ml, was added 50g as (t-Bu) (Me) Si (OEt) 2 to 25 ml, _Et 3 Al of n- heptane dilution _Et 3 Al, were 2hr reaction at 30 ° C. . The reaction product was thoroughly washed with purified n-heptane, and a portion of the resulting slurry was sampled and dried. As a result of analysis, the solid component contained 2.1 wt% Ti and 6.1 wt% (t-Bu) (Me) Si (OEt) ₂ .

Prepolymerization was performed by the following procedure using the solid component obtained above. Purified n-heptane was introduced into the slurry, and the solid component concentration was adjusted to 10 g / L. After cooling the slurry to 10 ° C., and 10g added n- heptane dilution of _Et 3 Al as _Et 3 Al, were fed over 2hr of propylene 150 g. After the supply of propylene was completed, the reaction was further continued for 30 minutes. Next, the gas phase was sufficiently replaced with nitrogen, and the reaction product was thoroughly washed with purified n-heptane. The obtained slurry was extracted from the autoclave and vacuum dried to obtain a solid catalyst component (B). This solid catalyst component (B) contained 1.2 g of polypropylene per 1 g of the solid component. As a result of analysis, the solid catalyst component (B) excluding polypropylene contained 1.6 wt% Ti and 5.5 wt% (t-Bu) (Me) Si (OEt) ₂ .

(Iii) Polymerization The inside of a stirring autoclave having an internal volume of 200 L was sufficiently substituted with propylene, and 80 L of purified n-heptane was introduced. After the temperature was raised to 70 ° C., 1.5 g of n- heptane dilution of _Et 3 Al as _Et 3 Al, hydrogen 5.0NL, and the solid catalyst component (B) 0.25 g (provided that a prepolymerized polymer excluded) Was introduced. After raising the temperature to 75 ° C., propylene was supplied so that the pressure became 0.7 MPaG, and polymerization was started. During the polymerization, the supply of propylene was continued so as to maintain the pressure. After 3 hours, 1 L of butanol was added to terminate the polymerization. The remaining propylene was purged and fully replaced with nitrogen. The obtained slurry was filtered with a centrifugal separator and then dried with a dryer to obtain PP (D-2).

(Production Example D-3)
Except having changed the quantity of hydrogen used in superposition | polymerization, it implemented similarly to manufacture example D-2, and obtained PP (D-3). The results are shown in Table 9.

(Production Example D-4)
(I) Production of solid component catalyst 20 liters of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel with a stirrer having an internal volume of 50 liters purged with nitrogen, and then 4 moles of magnesium chloride and 8 moles of tetrabutoxytitanium were introduced. After reacting at 95 ° C. for 2 hours, the temperature was lowered to 40 ° C., 480 ml of methylhydropolysiloxane (20 centistokes) was added, and the mixture was further reacted for 3 hours. Was washed with n-heptane.
Subsequently, 15 l of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel equipped with a stirrer as described above, then 3 mol of solid component was added in terms of magnesium atom, and 8 mol of silicon tetrachloride was added to 25 ml of n-heptane. The added mixed solution was introduced at 30 ° C. over 30 minutes, the temperature was raised to 90 ° C., and the mixture was reacted for 1 hour. Then, the reaction solution was taken out, and the produced solid component was washed with n-heptane.

Further, 5 l of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel equipped with a stirrer as described above, and then 250 g of the titanium-containing solid component treated with silicon tetrachloride obtained above, 750 g of 1,5-hexadiene, t -Butyl-methyl-dimethoxysilane (130 ml), divinyldimethylsilane (10 ml) and triethylaluminum (225 g) were introduced and contacted at 30 ° C. for 2 hours. The reaction solution was taken out and washed with n-heptane to obtain a solid component catalyst. It was.
The obtained solid component catalyst had a prepolymerization amount of 1,5-hexadiene of 2.97 g per titanium-containing solid component.

(Ii) Propylene / propylene-ethylene two-stage polymerization Propylene and triethylaluminum and polymerization in a first-stage reactor having an internal volume of 550 l under pressure at a temperature of 70 ° C (about 3.2 MPa at 70 ° C) The solid component catalyst in an amount such that the production rate was 20 kg / hour was continuously supplied, and hydrogen was also continuously supplied as a molecular weight regulator to carry out the first stage polymerization in the liquid phase. .
Subsequently, the produced polymer is introduced into a second-stage reactor having an internal volume of 1900 l via a propylene purge tank, and the composition ratio of the target copolymer is adjusted to a pressure of 3.0 MPa at a temperature of 60 ° C. Propylene and ethylene are continuously supplied according to the above, hydrogen is continuously supplied as a molecular weight regulator, and active hydrogen compound (ethanol) is supplied to the titanium atoms in the solid component catalyst supplied in the first stage. The polymerization was carried out in the gas phase by supplying 200-fold moles and 2.5-fold moles with respect to triethylaluminum, and the resulting polymer was continuously transferred to a vessel and then contained water. Nitrogen gas was introduced to stop the reaction (second stage polymerization).
Table 9 shows the analysis results of the obtained PP (D-4). The ethylene content in the propylene-ethylene copolymer was measured by the method described above.
PP (D-1) to PP (D-4) satisfy all the requirements in the present invention as the component (D). On the other hand, PP (D-5) does not satisfy the requirements of the present invention as component (D).

(5) Ethylene-α-olefin copolymer (D3) blended in component D for outer layer (2)
As a resin obtained in the following Production Example (D3-1) and a commercially available ethylene-α-olefin copolymer (D3-2), trade name “KERNEL” KF283 manufactured by Nippon Polyethylene Co., Ltd. was used. Various analysis results are shown in Table 10.

(Production Example D3-1)
A copolymer of ethylene and hexene-1 was prepared. The catalyst was prepared by the method described in JP-T-7-508545 (preparation of catalyst system). That is, to the complex dimethylsilylene bis (4,5,6,7-tetrahydroindenyl) hafnium dimethyl 2.0 mmol, tripentafluorophenyl boron was added in an equimolar amount to the above complex, and diluted to 10 liters with toluene. A catalyst solution was prepared.
A mixture of ethylene and 1-hexene was supplied to a stirred autoclave type continuous reactor having an internal volume of 1.5 liter so that the composition of 1-hexene was 73% by weight, and the pressure in the reactor was maintained at 130 MPa. The reaction was performed at 127 ° C. The polymer production per hour was about 2.5 kg.
After the reaction was completed, various analyzes of the obtained polymer were performed. Table 10 shows various analysis results of the obtained ethylene-α-olefin copolymer PE (D3-1).

(6) Propylene resin composition for inner layer (Z)
(6-1) Propylene resin composition (G)
Resins obtained in the following production examples (G-1) to (G-15) were used.

(Production Example G-1)
(I) Preparation of prepolymerized catalyst (chemical treatment of silicate)
To a 10-liter glass separable flask with a stirring blade, 3.75 liters of distilled water was added slowly followed by 2.5 kg of concentrated sulfuric acid (96%). At 50 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle size = 25 μm, particle size distribution = 10-60 μm) was dispersed, heated to 90 ° C., and maintained at that temperature for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake to reslurry it, and then filtered. This washing operation was performed until the pH of the washing solution (filtrate) exceeded 3.5. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 707 g.
(Drying silicate)
The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: Cylindrical inner diameter 50 mm Heating zone 550 mm (Electric furnace) Speed with rotating blade: 2 rpm Tilt angle: 20/520 Silicate feed rate: 2.5 g / min Gas flow rate: Nitrogen 96 liters / hour Countercurrent drying Temperature: 200 ° C (powder temperature)

(Preparation of catalyst)
An autoclave with an internal volume of 16 liters equipped with a stirring and temperature control device was thoroughly replaced with nitrogen. 200 g of dry silicate was introduced, 1160 ml of mixed heptane and 840 ml of a heptane solution of triethylaluminum (0.60 M) were added, and the mixture was stirred at room temperature. After 1 hour, the mixture was washed with mixed heptane to prepare 2,000 ml of silicate slurry. Next, 9.6 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added to the silicate slurry prepared above and reacted at 25 ° C. for 1 hour. In parallel, 187 ml of (r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] zirconium and 2,180 mg (0.3 mM) of mixed heptane Then, 33.1 ml of a heptane solution of triisobutylaluminum (0.71 M) was added and the mixture reacted at room temperature for 1 hour was added to the silicate slurry. After stirring for 1 hour, 5,000 ml was added with mixed heptane. Prepared.

(Prepolymerization / washing)
Subsequently, the temperature in the tank was raised by 40 ° C., and when the temperature was stabilized, propylene was supplied at a rate of 100 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours.
After completion of the prepolymerization, the remaining monomer was purged, the stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then the supernatant was decanted to 2,400 ml. Subsequently, 9.5 ml of a heptane solution of triisobutylaluminum (0.71 M / L) and 5,600 ml of mixed heptane were further added, stirred for 30 minutes at 40 ° C., allowed to stand for 10 minutes, and then 5,600 ml of the supernatant was removed. It was. This operation was further repeated 3 times. When the component analysis of the final supernatant was performed, the concentration of the organoaluminum component was 1.23 mM / L, the Zr concentration was 8.6 × 10 ⁻⁶ g / L, and the abundance in the supernatant with respect to the charged amount was It was 0.016%. Subsequently, 170 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added, followed by drying at 45 ° C. under reduced pressure. A prepolymerized catalyst containing 2.0 g of polypropylene per 1 g of catalyst was obtained.
Using this prepolymerized catalyst, a propylene-ethylene block copolymer was produced according to the following procedure.

(Ii) First polymerization step A horizontal reactor (L / D = 6, internal volume 100 liters) having a stirring blade was sufficiently dried, and the inside was sufficiently replaced with nitrogen gas. While stirring at a rotation speed of 30 rpm in the presence of a polypropylene powder bed, 0.568 g / hr of the prepolymerized catalyst adjusted by the above method (as the amount of solid catalyst excluding the prepolymerized powder) in the upstream part of the reactor, Triisobutylaluminum was continuously fed at 15.0 mmol / hr. The monomer mixed gas is continuously reacted so that the reactor temperature is maintained at 65 ° C., the pressure is maintained at 2.1 MPaG, the ethylene / propylene molar ratio in the reactor gas phase is 0.07, and the hydrogen concentration is 100 ppm. It was made to distribute | circulate in a container and vapor phase polymerization was performed. The polymer powder produced by the reaction was continuously extracted from the downstream portion of the reactor so that the amount of the powder bed in the reactor was constant. At this time, the amount of the polymer extracted when the steady state was reached was 10.0 kg / hr.
When the propylene-ethylene random copolymer obtained in the first polymerization step was analyzed, the MFR was 6.0 g / 10 min and the ethylene content was 2.2 wt%.

(Iii) Second polymerization step The propylene-ethylene copolymer extracted from the first step was continuously supplied to a horizontal reactor (L / D = 6, internal volume 100 liters) having a stirring blade. While stirring at a rotational speed of 25 rpm, the temperature of the reactor is maintained at 70 ° C., the pressure is maintained at 2.0 MPaG, and the ethylene / propylene molar ratio in the gas phase in the reactor is 0.453, and the hydrogen concentration is 330 ppm. A monomer mixed gas was continuously passed through the reactor to carry out gas phase polymerization. The polymer powder produced by the reaction was continuously extracted from the downstream portion of the reactor so that the amount of the powder bed in the reactor was constant. At this time, oxygen was supplied as an activity inhibitor so that the amount of polymer extracted was 17.9 kg / hr, and the polymerization reaction amount in the second polymerization step was controlled. The activity was 31.429 kg / g-catalyst.
Table 11 shows various analysis results of the propylene-based resin composition PP (G-1) thus obtained.

(Production Examples G-2 to 9)
Except for changing the polymerization conditions as shown in Table 11, catalyst preparation and polymerization were carried out in the same manner as in (Production Example G-1).
After the reaction was completed, various analyzes of the obtained polymer were performed. Table 11 shows various analysis results of the obtained propylene-based resin compositions PP (G-2) to PP (G-9). These satisfy all the requirements of the present invention as component (G).

(Production Examples G-10-15)
Except for changing the polymerization conditions as shown in Table 12, catalyst preparation and polymerization were carried out in the same manner as in (Production Example G-1).
After the reaction was completed, various analyzes of the obtained polymer were performed. Table 12 shows various analysis results of the obtained propylene-based resin compositions PP (G-10) to PP (G-15). These do not satisfy the requirements of the present invention as component (G).

(6-2) Ethylene-α-olefin copolymer (H) contained in propylene-based resin composition (Z) for inner layer (3)
The ethylene-α-olefin copolymers PE (H-1) to PE (H-4) obtained in the following production examples (H-1) to (H-4) and the following commercially available ethylene-α- Olefin copolymer PE (H-5) was used.
PE (H-5): Commercial product, trade name “KERNEL KF283” manufactured by Nippon Polyethylene
(Ethylene-α-olefin copolymer by metallocene catalyst)

(Production Example H-1)
A copolymer of ethylene and hexene-1 was prepared. The catalyst was prepared by the method described in JP-T-7-508545 (preparation of catalyst system). That is, to the complex dimethylsilylene bis (4,5,6,7-tetrahydroindenyl) hafnium dimethyl 2.0 mmol, tripentafluorophenyl boron was added in an equimolar amount to the above complex, and diluted to 10 liters with toluene. A catalyst solution was prepared.
A mixture of ethylene and 1-hexene was supplied to a stirred autoclave type continuous reactor having an internal volume of 1.5 liter so that the composition of 1-hexene was 73% by weight, and the pressure in the reactor was maintained at 130 MPa. The reaction was performed at 127 ° C. The polymer production per hour was about 2.5 kg.
After the reaction was completed, various analyzes of the obtained polymer were performed. Various analysis results of the obtained ethylene-α-olefin copolymer PE (H-1) are shown in Table 15.

(Production Example H-2 to 4)
Catalyst preparation and polymerization were carried out in the same manner as in Production Example (H-1) except that the composition of 1-hexene and the polymerization temperature during polymerization were changed as shown in Table 15.
After the reaction was completed, various analyzes of the obtained polymer were performed. Table 15 shows various analysis results of the obtained ethylene-α-olefin copolymers PE (H-2) to PE (H-4) and PE (H-5).
PE (H-1) to PE (H-4) satisfy all the requirements that are preferable in the present invention as the ethylene-α-olefin copolymer (H). On the other hand, PE (H-5) does not satisfy the requirements that are preferable in the present invention as the ethylene-α-olefin copolymer (H).

(6-3) Propylene resin (I) contained in propylene resin composition (Z) for inner layer (3)
Resins PP (I-1) to (I-3) obtained in the following production examples (I-1) to (I-3) and the following commercially available products were used. (PP (I-1) and PP (I-2) are homopolypropylenes obtained by single-stage polymerization, and PP (I-3) is a block copolymerized polypropylene obtained by multistage polymerization.

PP (I-4): Nippon Polypro's trade name “WINTEC WFW4”
(Propylene-ethylene random copolymer obtained by single-stage polymerization)
PP (I-5): Product name “WINTEC WFX4” manufactured by Nippon Polypro Co., Ltd.
(Propylene-ethylene random copolymer obtained by single-stage polymerization)
Table 16 shows the MFR and Tm of these materials.

(Production Example I-1)
(I) Production of Solid Component (A) A 10 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 2 L of purified n-heptane was introduced. Further, 250 g of MgCl ₂ and 1.8 L of Ti (On-Bu) ₄ were added, and a reaction was performed at 95 ° C. for 2 hours. The reaction product was cooled to 40 ° C. and 500 ml of methyl hydrogen polysiloxane (20 centistokes) was added. After 5 hours of reaction at 40 ° C., the precipitated solid product was thoroughly washed with purified n-heptane.
Subsequently, purified n-heptane was introduced to adjust the concentration of the solid product to 200 g / L. Here, 300 ml of SiCl ₄ was added and a reaction was carried out at 90 ° C. for 3 hours. The reaction product was thoroughly washed with purified n-heptane, and purified n-heptane was introduced so that the concentration of the reaction product was 100 g / L. A solution prepared by mixing 30 ml of phthalic dichloride with 270 ml of purified n-heptane was added thereto, and a reaction was performed at 90 ° C. for 1 hr. The reaction product was thoroughly washed with purified n-heptane, and purified n-heptane was introduced so that the concentration of the reaction product was 200 g / L. To this, 1 L of TiCl ₄ was added and a reaction was carried out at 95 ° C. for 3 hours. The reaction product was thoroughly washed with purified n-heptane to obtain a slurry of the solid component (A). A portion of this slurry was sampled and dried. As a result of analysis, the Ti content of the solid component (A) was 2.5 wt%.

(Ii) Preparation of Solid Catalyst Component (B) Next, a 20 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 100 g of the solid component (A) slurry was introduced as a solid component (A). Purified n-heptane was introduced to adjust the concentration of the solid component (A) to 20 g / L. Here, trimethyl vinyl silane 25 ml, was added 50g as (t-Bu) (Me) Si (OEt) 2 to 25 ml, _Et 3 Al of n- heptane dilution _Et 3 Al, were 2hr reaction at 30 ° C. . The reaction product was thoroughly washed with purified n-heptane, and a portion of the resulting slurry was sampled and dried. As a result of analysis, the solid component contained 2.1 wt% Ti and 6.1 wt% (t-Bu) (Me) Si (OEt) ₂ .
Prepolymerization was performed by the following procedure using the solid component obtained above. Purified n-heptane was introduced into the slurry, and the solid component concentration was adjusted to 10 g / L. After cooling the slurry to 10 ° C., and 10g added n- heptane dilution of _Et 3 Al as _Et 3 Al, were fed over 2hr of propylene 150 g. After the supply of propylene was completed, the reaction was further continued for 30 minutes. Next, the gas phase was sufficiently replaced with nitrogen, and the reaction product was thoroughly washed with purified n-heptane. The obtained slurry was extracted from the autoclave and vacuum dried to obtain a solid catalyst component (B). This solid catalyst component (B) contained 1.2 g of polypropylene per 1 g of the solid component. As a result of analysis, the solid catalyst component (B) excluding polypropylene contained 1.6 wt% Ti and 5.5 wt% (t-Bu) (Me) Si (OEt) ₂ .

(Iii) Polymerization The inside of a stirring autoclave having an internal volume of 200 L was sufficiently substituted with propylene, and 80 L of purified n-heptane was introduced. After the temperature was raised to 70 ° C., 1.5 g of n- heptane dilution of _Et 3 Al as _Et 3 Al, hydrogen 5.0NL, and the solid catalyst component (B) 0.25 g (provided that a prepolymerized polymer excluded) Was introduced. After raising the temperature to 75 ° C., propylene was supplied so that the pressure became 0.7 MPaG, and polymerization was started. During the polymerization, the supply of propylene was continued so as to maintain the pressure. After 3 hours, 1 L of butanol was added to terminate the polymerization. The remaining propylene was purged and fully replaced with nitrogen. The obtained slurry was filtered with a centrifugal separator and then dried with a dryer to obtain PP (I-1).

(Production Example I-2)
Except having changed the quantity of hydrogen used in superposition | polymerization, it implemented similarly to manufacture example I-1, and obtained PP (I-2). The results are shown in Table 16.

(Production Example I-3)
(I) Production of solid component catalyst 20 liters of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel with a stirrer having an internal volume of 50 liters purged with nitrogen, and then 4 moles of magnesium chloride and 8 moles of tetrabutoxytitanium were introduced. After reacting at 95 ° C. for 2 hours, the temperature was lowered to 40 ° C., 480 ml of methylhydropolysiloxane (20 centistokes) was added, and the mixture was further reacted for 3 hours. Was washed with n-heptane.
Subsequently, 15 l of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel equipped with a stirrer as described above, then 3 mol of solid component was added in terms of magnesium atom, and 8 mol of silicon tetrachloride was added to 25 ml of n-heptane. The added mixed solution was introduced at 30 ° C. over 30 minutes, the temperature was raised to 90 ° C., and the mixture was reacted for 1 hour. Then, the reaction solution was taken out, and the produced solid component was washed with n-heptane.

Further, 5 l of dehydrated and deoxygenated n-heptane was introduced into a reaction vessel equipped with a stirrer as described above, and then 250 g of the titanium-containing solid component treated with silicon tetrachloride obtained above, 750 g of 1,5-hexadiene, t -Butyl-methyl-dimethoxysilane (130 ml), divinyldimethylsilane (10 ml) and triethylaluminum (225 g) were introduced and contacted at 30 ° C. for 2 hours. The reaction solution was taken out and washed with n-heptane to obtain a solid component catalyst. .
The obtained solid component catalyst had a prepolymerization amount of 1,5-hexadiene of 2.97 g per titanium-containing solid component.

(Ii) Propylene / propylene-ethylene two-stage polymerization Propylene and triethylaluminum and polymerization in a first-stage reactor having an internal volume of 550 l under pressure at a temperature of 70 ° C (about 3.2 MPa at 70 ° C) The solid component catalyst in an amount such that the production rate is 20 kg / hour is continuously supplied, and hydrogen is also continuously supplied as a molecular weight regulator, and the first stage polymerization is carried out in the liquid phase. did.
Subsequently, the produced polymer is introduced into a second-stage reactor having an internal volume of 1900 l via a propylene purge tank, and the composition ratio of the target copolymer is adjusted to a pressure of 3.0 MPa at a temperature of 60 ° C. Propylene and ethylene are continuously supplied according to the above, hydrogen is continuously supplied as a molecular weight regulator, and active hydrogen compound (ethanol) is supplied to the titanium atoms in the solid component catalyst supplied in the first stage. The polymer was fed in a 200-fold mole and 2.5-fold mole with respect to triethylaluminum, the polymerization was carried out in the gas phase, the product polymer was continuously transferred to a vessel, Nitrogen gas was introduced to stop the reaction (second stage polymerization).
Table 16 shows the analysis results of the obtained PP (I-3). The ethylene content in the propylene-ethylene copolymer was measured by the method described above.

  PP (I-1) to (I-3) satisfy all the requirements that are preferable in the present invention as the propylene-based resin (I). On the other hand, PP (I-4) and (I-5) do not satisfy the requirements that are preferable in the present invention as the propylene-based resin (I).

(Examples, comparative examples and reference examples)
(1-i) Compound for intermediate layer (1) As propylene-based resin composition (X) for forming the inner layer, propylene-based resin compositions (component (A)) shown in the following tables, ethylene-α- Propylene-based resin composition obtained by measuring olefin copolymer (component (B)), propylene-based resin PP (component (C)) as component (C) so as to have the proportions shown in each table (X) is added to a Henschel mixer, and then 0.07 part by weight of the following antioxidant 1, 0.07 part by weight of the following antioxidant 2 and 100 parts by weight of the propylene-based resin composition (X) and 0.01 parts by weight of the following neutralizing agent was added and sufficiently stirred and mixed to obtain a compound.
Antioxidant 1: Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane (trade name: Irganox 1010, manufactured by Ciba Specialty Chemicals)
Antioxidant 2: Tris (2,4-di-t-butylphenyl) phosphite (trade name: Irgafos 168, manufactured by Ciba Specialty Chemicals Co., Ltd.)
-Neutralizing agent: calcium stearate (trade name Ca-St, manufactured by Nitto Kasei Kogyo Co., Ltd.)

(1-ii) Compound for outer layer (2) As propylene-based resin composition (Y) for forming the outer layer, the propylene-based resin (component (D)) shown in the following tables is used alone or as component (D ) And an ethylene-α-olefin copolymer (component (D3)) and other components (component (others)) were dry blended in the proportions shown in each table to obtain a compound.
(1-iii) Compound for inner layer (3) Propylene resin composition (component (G)) constituting propylene resin composition (Z) for forming inner layer, ethylene-α-olefin copolymer (component (H)), as propylene-based resin (component (I)), components (G), (H), (I) and others shown in the following tables are dry blended in the proportions described in the tables. I got a compound.

(2) Granulation Each compound obtained was melt-kneaded at a screw rotation speed of 200 rpm, a discharge rate of 10 kg / hr, and an extruder temperature of 190 ° C. in a PCM twin screw extruder manufactured by Ikegai Seisakusho with a screw diameter of 30 mm. The molten resin extruded from was taken out while being cooled and solidified in a cooling water tank, and the strand was cut into a diameter of about 2 mm and a length of about 3 mm using a strand cutter to obtain a raw material pellet.

(3) Manufacture of laminated sheet Each raw material pellet obtained was used as an intermediate layer extruder, a single screw extruder with a caliber of 50 mm, an extruder for an outer layer and an inner layer, using a single screw extruder with a caliber of 40 mm. Extruded from a circular die with a mandrel diameter of 100 mm and a Lip width of 3.0 mm at a set temperature of 200 ° C., water-cooled, and molded at a speed of 10 m / min, with a layer ratio of 1 (outer layer) / 8 (intermediate layer) / 1 (inner layer) ) To obtain a cylindrical molded body having a thickness of 200 μm. Next, after cutting one side of the obtained cylindrical molded body with a cutter to obtain a laminated sheet, the laminated sheet was conditioned for 24 hours or more in an atmosphere of 23 ° C. and 50% RH.

  The physical properties of the obtained laminated sheet were evaluated. The evaluation results are shown in the following table.

なお、上記実施例２９における外層（２）の欄の「７１２５」は、クラレ社製スチレン系エラストマー商品名「ハイブラー７１２５」である。

In addition, “7125” in the column of the outer layer (2) in Example 29 is a styrene elastomer product name “HIBLER 7125” manufactured by Kuraray Co., Ltd.

(About Examples 1-32)
The propylene-based resin multilayer sheets obtained in the above-described examples within the scope of the present application were excellent in flexibility, transparency, heat resistance, low-temperature impact properties, low-temperature heat sealability, cleanliness and proper secondary processing.

(About Comparative Examples 1-25)
Since the propylene-based resin multilayer sheet of the above comparative example obtained from outside the scope of the present application is poor in flexibility, it is difficult to discharge the inner solution or make the feel poor unless the air holes are opened. Moreover, transparency deteriorates and it is difficult to confirm the contents. The heat resistance cannot be maintained sufficiently, and internal fusion occurs in the sterilization process, and an avatar pattern (spotted pattern), wrinkles, and the like occur, deteriorating the appearance. Satisfactory low-temperature impact properties cannot be obtained, and cracking is likely to occur due to low-temperature transportation, dropping during storage, and the like. The low temperature heat sealability could not be sufficiently obtained, resulting in problems such as poor productivity and low energy efficiency due to the necessity of high temperature heat seal treatment.

(About Reference Examples 1-5)
When preferred additional components that may be further blended in the present application are used, it can be seen that there is a difference in performance depending on the additional components used.

  When considering each of the above Examples and each Comparative Example, and also with reference examples as necessary, it can be obtained from the combination of the novel propylene-based resin composition of the present invention that satisfies the respective regulations in the configuration of the present invention. Propylene-based resin multilayer sheets are excellent in flexibility, transparency, heat resistance, low-temperature impact resistance, low-temperature heat sealability, cleanliness, and formability such as poor appearance such as interface roughness and thickness fluctuation hardly occur during multilayer molding. It is clear that a propylene-based resin multilayer sheet excellent in strength and appearance can be obtained because the phenomenon that the molten resin flows and becomes thin even under severe heat sealing conditions is difficult to occur.

  The propylene-based resin multilayer sheet of the present invention is excellent in flexibility, transparency, heat resistance, low-temperature impact resistance, low-temperature heat sealability, cleanliness, and poor appearance such as interface roughening and thickness fluctuation hardly occur during multilayer molding. This is a propylene-based resin multi-layer sheet that is excellent in secondary processing and has excellent bag breaking strength because the molten resin does not flow and thins even under severe heat sealing conditions. Heat treatment using the same The packaging bag is extremely useful for infusion bags and retort packaging bags.

Claims (5)

A propylene-based resin multilayer sheet, which is a multilayer sheet composed of at least three layers in the order of an outer layer, an intermediate layer, and an inner layer, and each layer satisfies the following conditions.
(1) Intermediate layer The propylene resin composition (X) constituting the intermediate layer satisfies the following conditions (Ai) to (A-iii): 60 to 90 wt% of the propylene resin composition (A) , and An ethylene-α-olefin copolymer (B) satisfying the following conditions (Bi) to (B-ii) is contained in an amount of 40 to 10 wt%.
Propylene resin composition (A):
(Ai) 30 to 70 wt% of a propylene-α-olefin random copolymer (A1) having a melting peak temperature (Tm (A1)) of 125 to 145 ° C., an ethylene content obtained using a metallocene catalyst ( E [A2]) is obtained by mixing 70 to 30 wt% of a propylene-ethylene random copolymer (A2) having 7 to 17 wt% by a method other than the polymerization blend method.
(A-ii) Melt flow rate (MFR (A): 230 ° C., 2.16 kg) is in the range of 0.5 to 20 g / 10 min.
(A-iii) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the peak of the tan δ curve representing the glass transition observed in the range of −60 to 20 ° C. is less than 0 ° C. One peak is shown.
-Ethylene-α-olefin copolymer (B):
(Bi) The density is in the range of 0.860 to 0.910 g / cm ³ .
(B-ii) The melt flow rate (MFR (B): 190 ° C., 2.16 kg) is in the range of 0.1 to 20 g / 10 minutes.
(2) Outer layer The propylene-based resin composition (Y) constituting the outer layer contains a propylene-based resin (D) having a melting peak temperature Tm (D) in the range of 135 to 170 ° C.
(3) Inner layer The propylene-based resin composition (Z) constituting the inner layer is a propylene-based resin composition (G) that satisfies the following conditions (G-i) to (G-ii) (45) to 89 wt%, and the following condition (H The ethylene-α-olefin copolymer (H) satisfying -i) is contained in an amount of 10 to 30 wt%, and the propylene resin (I) satisfying the following condition (Ii) is contained in an amount of 1 to 25 wt%.
Propylene resin composition (G):
(Gi) Using a metallocene-based catalyst, 50 to 60 wt% of a propylene-α-olefin random copolymer component (G1) having a melting peak temperature Tm (G1) of 125 to 135 ° C. in DSC measurement in the first step. The propylene-ethylene block copolymer obtained by sequentially polymerizing 50-40 wt% of the propylene-ethylene random copolymer component (G2) having an ethylene content (E [G2]) of 8-14 wt% in the second step It is a coalescence.
(G-ii) In the temperature-loss tangent (tan δ) curve obtained by solid viscoelasticity measurement (DMA), the peak of the tan δ curve representing the glass transition observed in the range of −60 to 20 ° C. is simply below 0 ° C. One peak is shown.
-Ethylene-α-olefin copolymer (H):
(Hi) The density is in the range of 0.860 to 0.910 g / cm ³ .
Propylene resin (I):
(Ii) The melting peak temperature Tm (I) is higher by 6 ° C. or more than the melting peak temperature Tm (G1).   2. The propylene according to claim 1, wherein the propylene-α-olefin random copolymer component (A1) in the propylene-based resin composition (A) is obtained using a metallocene catalyst. -Based resin multilayer sheet. The propylene resin composition (X) constituting the intermediate layer further contains a propylene resin (C) that satisfies the following conditions (Ci) to (C-ii), and the composition of the resin composition (X) is: The propylene resin composition (A) is 45 to 89 wt%, the ethylene-α-olefin copolymer (B) is 10 to 30 wt%, and the propylene resin (C) is 1 to 25 wt%. Or the propylene-type resin multilayer sheet of 2.
Propylene resin (C):
(Ci) The melting peak temperature (Tm (C)) is 6 ° C. or more higher than the melting peak temperature (Tm (A1)) of the propylene-α-olefin random copolymer (A1).
(C-ii) The melt flow rate (MFR (C): 230 ° C., 2.16 kg) is in the range of 0.5 to 30 g / 10 minutes.   The package for heat processing which uses the propylene-type resin multilayer sheet of any one of Claims 1-3.   The package for heat treatment according to claim 4, wherein the package for heat treatment is an infusion bag.