JP6331720B2 - Polypropylene resin composition for battery packaging and film - Google Patents

Description

  The present invention relates to a polypropylene resin composition and a film for battery packaging. More specifically, the present invention has not only excellent heat resistance, sealing properties, and moldability, but also high sealing strength and impact resistance, and resistance to deformation during deformation processing. The present invention relates to a polypropylene resin composition and a film for battery packaging that are excellent in whitening and cracking resistance.

Polypropylene materials have been widely used as packaging materials due to their heat resistance and packaging suitability, as well as economy and environmental problem adaptability.
In addition, diversification of adaptive applications has progressed, not only for food packaging applications, but also for industrial applications such as protective films for the purpose of preventing surface scratches on automobile exteriors, parts, or LCD TV members, and fixed films when processing silicon wafers. The advancement of is also conspicuous. Among them, one of the fields in which development has been remarkable in recent years is battery packaging materials.

  In particular, secondary batteries called lithium-ion batteries have superior characteristics such as high voltage, high energy density, and reduced capacity reduction due to discharge, compared to conventional secondary batteries. This has greatly contributed to long-term driving and downsizing of mobile devices such as. Recently, it is also used in hybrid vehicles and electric vehicles, and is a battery that is expected to be actively developed in the future.

  The principle of the lithium ion battery is that charging / discharging is performed when lithium ions in an electrolyte solution responsible for electric transfer travel between two electrodes, a positive electrode and a negative electrode, through an ion selective membrane called a separator. In configuring a lithium ion battery, it is necessary to wrap the positive electrode, the negative electrode, the electrolytic solution, and the separator with an exterior body in order to prevent undesired oxidation-reduction reactions and deterioration.

Examples of the exterior body include a metal can type obtained by processing a metal plate into a cylindrical shape or a rectangular parallelepiped shape, and a pouch type composed of a composite film such as a base material layer, a metal foil layer, and a seal layer.
The metal can type is a so-called dry battery, which is often found in conventional batteries and is very robust, but it has a small degree of freedom in the shape of the battery itself, a heavy weight, and poor heat dissipation. Have

  On the other hand, the pouch type is lighter and has better heat dissipation than the metal can type, and also has a high degree of design freedom. Moreover, since it is possible to supplement the robustness by storing the pouch in a plastic case at the time of use, it is an excellent package that is widely applied not only for mobile use but also for electric vehicles.

However, many of the sealant materials that make up pouches have not been developed as battery packaging materials, but can be used to divert general-purpose sealant materials, such as those for existing food packaging, that existed in the market. It stays (for example, refer patent documents 1-3).
On the other hand, recently, an invention of a sealant material for battery packaging has been found (see Patent Document 4). However, the invention is characterized in that a specific elastomer is blended when using a propylene resin as a sealant. The propylene resin as the main sealant material is still clear about the specific invention and material design. There is no conversion.
Therefore, development of a sealant material having excellent characteristics as a battery packaging material has been awaited from the market.

JP 2002-245980 A JP 2005-56729 A JP 2007-273398 A JP 2008-277274 A

  In view of the above-mentioned problems of the prior art, the object of the present invention is not only excellent in heat resistance, sealing performance and moldability, but also has high sealing strength and impact resistance, and is resistant to whitening and cracking during deformation processing. The object is to provide a polypropylene-based resin composition for battery packaging and a film which are excellent in performance and the like.

  As a result of earnest research to develop a polypropylene-based material having the above-described characteristics and a film thereof, the present inventor has found that the above object can be achieved by a film mainly composed of a specific propylene-ethylene block copolymer. Based on the finding and these findings, the present invention has been completed.

  The present invention uses a propylene-ethylene block copolymer (A) obtained by multistage polymerization of propylene and ethylene comprising a propylene-based polymer component (A1) and a propylene-ethylene random copolymer component (A2), Since various performances as a packaging film for batteries are improved in a well-balanced manner, the ethylene content and the MFR of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2) are each within a specific range. The main feature of the present invention is that the propylene-ethylene block copolymer (A) is set.

That is, according to 1st invention of this invention, the propylene-type polymer component (A1) and propylene-ethylene random copolymer component (A2) which satisfy | fill the conditions of following (a1)-(a4) obtained by multistage polymerization. And a propylene-ethylene block copolymer (A) containing a polypropylene resin composition for battery packaging films.
-Propylene-ethylene block copolymer (A);
(A1) The propylene polymer component (A1) is a propylene homopolymer or copolymer having an ethylene content of 0 to 2% by weight.
(A2) The MFR (230 ° C., 2.16 kg load) of the propylene-based polymer component (A1) is 1.0 to 10 g / 10 min.
(A3) The propylene-ethylene random copolymer component (A2) has an ethylene content of 10 to 40% by weight.
(A4) The MFR (230 ° C., 2.16 kg load) of the propylene-ethylene random copolymer component (A2) is 0.5 to 5 g / 10 minutes.

  According to the second invention of the present invention, in the first invention, the fatty acid amide-based lubricant is further added in an amount of 0.03 to 0 with respect to 100 parts by weight of the propylene-ethylene block copolymer (A). The polypropylene resin composition for battery packaging films characterized by containing .5 parts by weight is provided.

According to a third aspect of the present invention, there is provided a single-layer sealant film obtained by melt extrusion film-forming a polypropylene resin composition for battery packaging film according to the first or second aspect of the invention. Provided.
Furthermore, according to the fourth invention of the present invention, the polypropylene resin composition for battery packaging film according to the first or second invention is used for at least one side layer of both outer layers and obtained by melt extrusion film formation. A multilayer sealant film is provided.

  According to a fifth aspect of the present invention, there is provided a film characterized in that the single-layer or multi-layer sealant film according to the third or fourth aspect is used as a sealant for battery packaging materials.

  The polypropylene resin composition of the present invention is not only excellent in moldability, but also has high sealing strength and impact resistance as a battery packaging film, in addition to essential performance such as heat resistance and sealing performance, and is deformed. The whitening resistance and cracking resistance at the time are improved in a well-balanced manner, and an exceptional effect that has not been seen in the past is exhibited.

The polypropylene resin composition of the present invention is a resin composition used for battery packaging, and is a propylene-ethylene block copolymer (A) satisfying the above (a1) to (a4) obtained by multistage polymerization. It is characterized by comprising.
Hereinafter, each component which comprises the polypropylene resin composition of this invention is demonstrated in detail.

1. Propylene-ethylene block copolymer (A)
The propylene-ethylene block copolymer (A) obtained by multistage polymerization used in the polypropylene resin composition for battery packaging film of the present invention has a propylene homopolymer having an ethylene content [E (A1)] of 0 to 2% by weight. A propylene-ethylene block comprising a propylene-based polymer component (A1) which is a polymer or a copolymer, and a propylene-ethylene random copolymer component (A2) having an ethylene content [E (A2)] of 10 to 40% by weight It is a copolymer.

(1) Ethylene content of propylene polymer component (A1) The ethylene content [E (A1)] of the propylene polymer component (A1) needs to be 0 to 2% by weight.
When the ethylene content [E (A1)] of the propylene-based polymer component (A1) exceeds 2% by weight, the crystallinity decreases and the shrinkage ratio increases or deforms under heating conditions of the film. Means decline. The lithium ion battery which is the application of the present invention needs to be interrupted by a physical or mechanical safety device when abnormal heat is generated, but the heat resistance of the sealant film is reduced before the circuit is interrupted. It is very dangerous because it leads to runaway battery circuit due to leakage of contents.

The propylene-ethylene random copolymer component (A2) is a component that contributes to the flexibility and impact resistance of the propylene-ethylene block copolymer (A). This component is polymerized mainly as a propylene-ethylene random copolymer after the second stage of the multistage polymerization method.
Here, unless departing from the spirit of the present invention, it may be further copolymerized with other α-olefins such as 1-butene, 1-hexene, 1-octene and the like.

(2) MFR of propylene polymer component (A1)
MFR [MFR (A1)] at 230 ° C. and a load of 2.16 kg of the propylene-based polymer component (A1) is 1.0 to 10 g / 10 minutes, and further 2.0 to 5.0 g / 10 minutes. Is preferred. When the MFR (A1) is less than 1.0 g / 10 min, the extrusion moldability is insufficient, and when the film is further formed into a film, poor appearance due to fish eyes is caused. On the other hand, if MFR (A1) exceeds 10 g / 10 min, impact resistance and seal strength will be insufficient.
The melt flow rate [MFR (A1)] is measured at 230 ° C. and a load of 2.16 kg according to JIS K7210.

(3) Ratio of component (A1) and component (A2) The ratio of the propylene-ethylene random copolymer component (A2) in the propylene-ethylene block copolymer (A) is preferably 5 to 40% by weight, and 10 to 35% by weight is preferred. In other words, the proportion of the propylene-based polymer component (A1) is preferably 60 to 95% by weight, and more preferably 65 to 90% by weight.
When the ratio of the component (A2) is 40% by weight or less, the heat resistance is improved, and stickiness and bleeding out at the time of film formation are easily suppressed, and the ratio of the component (A2) is 5% by weight or more. In such a case, the amount of the component (A2) that contributes to flexibility and whitening resistance is sufficient, and the flexibility and whitening resistance are improved.

(4) Ethylene content of propylene-ethylene random copolymer component (A2) The ethylene content [E (A2)] in the propylene-ethylene random copolymer component (A2) needs to be 10 to 40% by weight. 15 to 35% by weight is more preferable.
When the ethylene content [E (A2)] of the propylene-ethylene random copolymer component (A2) exceeds 40% by weight, the compatibility of the copolymer component (A2) with the propylene-based polymer component (A1) is high. This causes a decrease in whitening resistance and cracking resistance. Moreover, when [E (A2)] is less than 10% by weight, impact resistance is lowered.

(5) MFR of propylene-ethylene random copolymer component (A2)
The MFR [MFR (A2)] of the propylene-ethylene random copolymer component (A2) needs to be 0.5 to 5 g / 10 min, and more preferably 0.6 to 4.0 g / min.
When the MFR (A2) is less than 0.5 g / 10 min, the orientation of the copolymer component (A2) is lowered during film forming, causing deterioration of film transparency, and further reducing whitening resistance. Cause. On the other hand, when MFR (A2) exceeds 5 g / 10 min, the low molecular weight component of the copolymer (A) component becomes excessive, which causes deterioration of film stickiness and contamination of bleeds in battery cells.

2. Propylene-ethylene block copolymer production method The propylene-ethylene block copolymer (A) used in the present invention may be produced by any production method as long as it has the above physical properties. Can be preferably manufactured.

(1) Raw material used In producing the propylene-ethylene block copolymer (A) used in the present invention, the catalyst used is a magnesium-supported catalyst having magnesium, halogen, titanium, and an electron donor as catalyst components. Alternatively, a catalyst comprising a solid catalyst component using titanium trichloride as a catalyst and an organic aluminum, or a metallocene catalyst can be used.
Although the specific manufacturing method of a catalyst is not specifically limited, The Ziegler catalyst disclosed by Unexamined-Japanese-Patent No. 2007-254671 can be illustrated as an example.

  The raw material olefin to be polymerized is propylene or ethylene, and if necessary, other olefins that do not impair the object of the present invention, such as 1-butene, 1-hexene, 1-octene, 4-methyl-pentene. -1 etc. can also be used.

(2) Polymerization step The polymerization step performed in the presence of the catalyst includes a polymerization step (i) for producing a propylene polymer, a polymerization step for polymerizing ethylene to propylene in a proportion of 10 to 40% by weight of ethylene. It consists of two stages ii).

(2-1) Polymerization step (i);
In the polymerization step (i), a propylene homopolymer or a propylene / ethylene mixture is supplied to a polymerization system to which the catalyst is added, and a propylene homopolymer or a propylene polymer component having an ethylene content of 2% by weight or less ( In this step, A1) is formed so as to be an amount corresponding to 60 to 95% by weight of the total polymer amount.

Below, the manufacturing method of a propylene-type copolymer component (A1) is demonstrated.
The MFR (A1) of the propylene-based polymer component (A1) can be adjusted by using hydrogen as a chain transfer agent.
Specifically, when the concentration of hydrogen as a chain transfer agent is increased, the MFR (A1) of the propylene-based polymer component (A1) is increased. The reverse is also true. In order to increase the concentration of hydrogen in the polymerization tank, it is only necessary to increase the amount of hydrogen supplied to the polymerization tank, and adjustment is very easy for those skilled in the art.
When the propylene polymer component (A1) is a propylene-ethylene random copolymer, it is convenient to use a method for controlling the amount of ethylene supplied to the polymerization tank as a means for controlling the ethylene content. is there. Specifically, if the amount ratio of ethylene to propylene supplied to the polymerization tank (ethylene supply amount ÷ propylene supply amount) is increased, the ethylene content of the resulting propylene polymer component (A1) is increased. The reverse is also true.
The relationship between the amount ratio of propylene and ethylene supplied to the polymerization tank and the ethylene content of the resulting propylene polymer component (A1) varies depending on the type of catalyst used, but by adjusting the supply amount ratio as appropriate, It is very easy for those skilled in the art to obtain the propylene-based polymer component (A1) having the desired ethylene content.

(2-2) Polymerization step (ii);
In the polymerization step (ii), following the polymerization step (i), a propylene / ethylene mixture is further introduced to obtain a propylene-ethylene random copolymer component (A2) having an ethylene content of 10 to 40% by weight. is there.
In this step, a polymer corresponding to 5 to 40% by weight of the total polymer amount is formed.
Below, the manufacturing method of a propylene-ethylene random copolymer component (A2) is demonstrated.
The MFR (A2) of the propylene-ethylene random copolymer component (A2) can be adjusted by using hydrogen as a chain transfer agent.
A specific control method is the same as the MFR control method of the propylene-based polymer component (A1).
Further, as a means for controlling the ethylene content of the propylene-ethylene random copolymer component (A2), it is convenient to use a method for controlling the amount of ethylene supplied to the polymerization tank. The specific control method is the same as the case where the propylene-based polymer component (A1) is a propylene-ethylene random copolymer.

(3) Index Control Method for Propylene-Ethylene Block Copolymer (A) Next, a method for controlling the index of the propylene-ethylene block copolymer (A) will be described.
The propylene-ethylene block copolymer (A) of the present invention comprises a propylene-based polymer component (A1) and a propylene-ethylene random copolymer component (A2). Therefore, items to be considered in controlling the index of the propylene-ethylene block copolymer (A) are ethylene content [E (A)], MFR (A), propylene-based polymer component (A1) and propylene. -It is three of the weight ratio of an ethylene random copolymer component (A2).

First, the control method of the weight ratio of the propylene polymer component (A1) and the propylene-ethylene random copolymer component (A2) will be described.
The weight ratio of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2) is the same as the production amount in the polymerization step (i) for producing the propylene-based polymer component (A1) and the propylene-ethylene random copolymer. It controls by the manufacturing amount in the superposition | polymerization process (ii) which manufactures a polymer component (A2). For example, in order to increase the amount of the propylene-based polymer component (A1) and reduce the amount of the propylene-ethylene random copolymer component (A2), the polymerization step is performed while maintaining the production amount of the polymerization step (i). What is necessary is just to reduce the production amount of (ii), and what is necessary is just to shorten the residence time of polymerization process (ii), or to reduce polymerization temperature. In addition, it can be controlled by adding a polymerization inhibitor such as ethanol or oxygen or increasing the amount of addition when it is originally added. The reverse is also true.
Usually, the weight ratio of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2) depends on the production amount in the polymerization step (i) for producing the propylene-based polymer component (A1), and the propylene- It is defined by the production amount in the polymerization step (ii) for producing the ethylene random copolymer component (A2).
The formula is shown below.
Weight of component (A1): Weight of component (A2) = W (A1): W (A2)
W (A1) = Production amount of polymerization step (i) ÷ (Production amount of polymerization step (i) + Production amount of polymerization step (ii))
W (A2) = Production amount of polymerization step (ii) ÷ (Production amount of polymerization step (i) + Production amount of polymerization step (ii))
W (A1) + W (A2) = 1
(W (A1) and W (A2) are weight ratios of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2) in the propylene-ethylene block copolymer (A), respectively. .)

  In an industrial production facility, the production amount is usually obtained from the heat balance and material balance of each polymerization tank. When the crystallinity of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2) are sufficiently different, both are analyzed using an analytical method such as TREF (temperature rising temperature elution fractionation method). May be separated and identified to determine the quantitative ratio. A technique for evaluating the crystallinity distribution of polypropylene by TREF measurement is well known to those skilled in the art. Glokner, J. et al. Appl. Polym. Sci: Appl. Poly. Symp. 45, 1-24 (1990), L .; Wild, Adv. Polym. Sci. 98, 1-47 (1990), J .; B. P. Soares, A .; E. Detailed measurement methods are shown in documents such as Hamielec, Polymer; 36, 8, 1639-1654 (1995).

Next, a method for controlling the ethylene content [E (A)] will be described.
Since the propylene-ethylene block copolymer (A) is a mixture of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2), the relationship between the respective ethylene contents is as follows. The formula holds.
E (A) = E (A1) × W (A1) + E (A2) × W (A2)
(Here, E (A), E (A1), E (A2) are respectively a propylene-ethylene block copolymer (A), a propylene-based polymer component (A1), and a propylene-ethylene random copolymer component. (The ethylene content of (A2).)
This formula shows the material balance regarding ethylene content.

Therefore, if the weight ratio of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2) is determined, that is, if W (A1) and W (A2) are determined, E (A) is It is uniquely determined by E (A1) and E (A2). That is, by controlling the weight ratio of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2), E (A1), and E (A2), E (A) can be controlled. Can be controlled. For example, in order to increase E (A), E (A1) may be increased or E (A2) may be increased. If it is noted that E (A2) is higher than E (A1), it can be easily understood that W (A1) may be reduced and W (A2) may be increased. The reverse control method is the same.
In addition, it is E (A) and E (A1) that the measurement value can be actually obtained directly, and E (A2) is calculated using the measurement value of both. Therefore, if an operation to increase E (A2), that is, an operation to increase the amount of ethylene supplied to the polymerization step (ii) is selected as a means when performing an operation to increase E (A), the measured value Is E (A) and not E (A2), but it is obvious that the reason why E (A) increases is that E (A2) increases.

Finally, a method for controlling MFR (A) will be described.
In the present invention, MFR (A2) is defined by the following equation.
MFR (A2) = exp {(log _e [MFR (A)] − W (A1) × log _e [MFR (A1)]) ÷ W (A2)}
(Here, log _e is a logarithm with e as the base. MFR (A), MFR (A1), and MFR (A2) are respectively a propylene-ethylene block copolymer (A) and a propylene-based polymer. (It is MFR of a component (A1) and a propylene-ethylene random copolymer component (A2).)
This equation is an empirical formula generally called logarithm addition rule of viscosity log _e [MFR (A)] = W (A1) × log _e [MFR (A1)] + W (A2) × log _e [MFR (A2)]
It is a modified version and is used daily in the industry.

In order to define by this formula, the weight ratio of the propylene-based polymer component (A1) and the propylene-ethylene random copolymer component (A2), MFR (A), MFR (A1), and MFR (A2) are independently Absent. Therefore, to control MFR (A), the weight ratio of propylene-based polymer component (A1) and propylene-ethylene random copolymer component (A2), MFR (A1), and MFR (A2) are set to three factors. Control is sufficient. For example, in order to increase MFR (A), MFR (A1) may be increased or MFR (A2) may be increased. It can also be easily understood that when MFR (A2) is lower than MFR (A1), MFR (A) can be increased even if W (A1) is increased and W (A2) is decreased. Like. The reverse control method is the same.
It is to be noted that MFR (A) and MFR (A1) can actually obtain the measured values directly, and MFR (A2) is calculated using the measured values of both. Therefore, if an operation for increasing the MFR (A2), that is, an operation for increasing the amount of hydrogen supplied to the polymerization step (ii) is selected as a means when performing an operation for increasing the MFR (A), the measured value Is MFR (A) and not MFR (A2), but it is obvious that the reason why MFR (A) increases is that MFR (A2) increases.

  The polymerization process of the propylene-ethylene block copolymer can be carried out by either a batch method or a continuous method. At this time, a method of performing polymerization in an inert hydrocarbon solvent such as hexane or heptane, a method of using propylene as a solvent substantially without using an inert solvent, a gas without using a liquid solvent substantially. It is possible to employ a method in which polymerization is carried out in the above monomer and a method in which these are combined. In addition, the polymerization step (i) and the polymerization step (ii) may use the same polymerization tank or separate polymerization tanks.

3. Other components (1) Fatty acid amide-based lubricant In addition, the polypropylene-based resin composition of the present invention contains a fatty acid amide-based lubricant for the purpose of improving the slipperiness of the resulting film and handling properties during deformation processing. 0.03-0.5 weight part can be added with respect to 100 weight part of ethylene block copolymer (A).
Specific examples of fatty acid amide-based lubricants include stearic acid amide, oleic acid amide, erucic acid amide, methylene bis stearic acid amide, and ethylene bis stearic acid amide.

  It is preferable that the content of the fatty acid amide-based lubricant is 0.5 parts by weight or less because the amount of lubricant bleed onto the film surface becomes an appropriate amount, and the adhesive strength with the metal layer is hardly reduced and the electrolyte solution is hardly contaminated. Moreover, since 0.03 weight part or more can anticipate the improvement of slipperiness and can anticipate the effect of addition, it is more preferable to use in 0.03-0.5 weight part.

(2) Olefin Copolymer Elastomer In addition, the polypropylene resin composition of the present invention further contains an olefin copolymer elastomer as a propylene-ethylene block copolymer (for the purpose of improving the flexibility of the film). A) 3 to 30 parts by weight can be added to 100 parts by weight.
The density of the olefin copolymer elastomer is preferably 0.880~0.910g / cm ^3, more preferably from 0.885~0.907g / cm ^3. A density of 0.910 g / cm ³ or less is preferable because whitening resistance and cracking resistance during deformation processing are improved and an effect of improving flexibility is seen.
Here, the density is a value measured according to JIS K7112.

Moreover, it is preferable that the melt flow rate (MFR) of an olefin copolymer elastomer exists in the range of 0.5-10 g / 10min. When the melt flow rate (MFR) of the ethylene-α-olefin copolymer is 0.5 g / 10 min or more, the extrusion characteristics at the time of film formation become good, and there is a high possibility of affecting the productivity of the film. Therefore, it is preferable.
Further, it is preferable that the melt flow rate (MFR) is 10 g / 10 min or less because stickiness and bleed-out hardly occur and impact resistance is improved.
MFR here is a value measured according to JIS K7210 at a heating temperature of 190 ° C. and a load of 21.18 N (2.16 kg).

  The content of the olefin copolymer elastomer in the polypropylene resin resin composition is preferably in the range of 3 to 20 parts by weight with respect to 100 parts by weight of the propylene-ethylene block copolymer (A). By suppressing the content to 20 parts by weight or less, it is possible to obtain a battery packaging film without impairing the heat resistance and rigidity inherent in the propylene-ethylene block copolymer according to the present invention. Furthermore, when the content is 20 parts by weight or less, it is preferable that the rigidity, stickiness, and seal strength are less likely to occur. If the amount is 3 parts by weight or more, improvement in flexibility can be expected, and the effect of addition can be expected. Therefore, it is more preferable to use in the range of 3 to 20 parts by weight.

  The monomer related to the main polymer in the olefin copolymer elastomer is preferably selected from any one of ethylene, propylene and 1-butene, and the comonomer is preferably ethylene or a carbon number of 3 to 10 The α-olefin and the alkadiene having 4 to 10 carbon atoms are at least one different in structure from the main polymer, and the comonomer content is desirably 10% by weight or more. When the comonomer content is 10% by weight or more, the flexibility is improved, the impact resistance is good, and the combined effect becomes remarkable.

As the comonomer, ethylene, propylene, 1-butene, 1-hexene and 1-octene are preferable.
Preferable representative examples of the olefin copolymer elastomer include ethylene-propylene copolymer elastomer, ethylene-propylene-butene copolymer elastomer, ethylene-butene copolymer elastomer, ethylene-hexene copolymer elastomer, ethylene-octene. Examples include copolymer elastomers, ethylene-propylene-butadiene copolymers, ethylene-propylene-isoprene copolymer elastomers, propylene-butene copolymer elastomers, and the like.

(3) Other blends In the polypropylene resin composition for battery packaging film of the present invention, a propylene-ethylene block copolymer or propylene having a composition different from that of the present invention is within the range not impairing the effects of the present invention. A polymer, a propylene-ethylene random copolymer, a propylene-ethylene-butene random copolymer, or a styrene elastomer may be added as appropriate.
In addition, antioxidants, ultraviolet absorbers, neutralizers, nucleating agents, light stabilizers, antistatic agents, antiblocking agents, lubricants, odor adsorbents, antibacterial agents, pigments, inorganic and organic fillers, and various Known additives such as synthetic resins can be added as needed.

4). Film molding The battery packaging film of the present invention is excellent in heat resistance, sealing performance, moldability, high sealing strength and impact resistance, whitening resistance during deformation processing, cracking resistance, etc., and mainly as an unstretched film. When used, the effect is sufficiently exhibited.
The film can be obtained by melt extrusion film formation, and can be produced by a casting method, an inflation method or the like that is generally performed industrially.
Moreover, the film of this invention can be used also as a single layer film using the said polypropylene resin composition, and a laminated film.
In the case of a laminated film, it is preferable that the layer made of the resin composition of the present invention is used as at least the outermost sealant layer and is 10% or more of the total film thickness. The film thickness is preferably 5 to 200 μm, and more preferably 10 to 100 μm.
Further, the surface of the film can be subjected to corona discharge treatment, flame treatment, ozone treatment, etc. in order to improve the wettability of the surface.

  In producing a film from the polypropylene resin composition of the present invention, a propylene-ethylene block copolymer (A) and, if necessary, a fatty acid amide-based lubricant, an ethylene-α-olefin copolymer elastomer, etc. A mixture and pelletized with an extruder may be supplied to a film forming machine to form a film. In addition, a propylene-ethylene block copolymer (A) and, if necessary, a fatty acid amide system at the time of film production Each of the above-mentioned lubricants and ethylene-α-olefin copolymer elastomer pellets may be supplied to a film forming machine to form a film.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is limited and interpreted by the following examples.
The detailed description of the present invention and the measurement of physical properties and analysis values of each item in the examples are according to the following methods.

(1) Measurement of ethylene content in copolymer The propylene-based polymer component (A1) obtained at the end of the first polymerization step and the propylene-ethylene block copolymer obtained through the second polymerization step Each ethylene content in (A) was calculated | required by analyzing the ¹³ C-NMR spectrum measured according to the following conditions by the proton complete decoupling method.
Model: JSX Corporation GSX-400 or equivalent device (carbon nuclear resonance frequency 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 count: 5,000 times or more

The spectrum may be assigned with reference to Macromolecules 17, 1950 (1984), for example. The attribution of spectra measured under the above conditions is as shown in Table 1 below. In the table, symbols such as S _αα are in accordance with the notation of Carman et al. (Macromolecules 10, 536 (1977)), P is methyl carbon, S is methylene carbon, and T is 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), 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 (T _ββ ) (1)
[PPE] = k × I (T _βδ ) (2)
[EPE] = k × I (T _δδ ) (3)
[PEP] = k × I (S _ββ ) (4)
[PEE] = k × I (S _βδ ) (5)
[EEE] = k × {I (S _δδ ) / 2 + I (S _γδ ) / 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 (T _ββ ) means the intensity of the peak at 28.7 ppm attributed to T _ββ .
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

In addition, conversion from mol% of ethylene content to weight% is performed using the following formula | equation.
Ethylene content (% by weight) = (28 × X / 100) / {28 × X / 100 + 42 × (1−X / 100)} × 100
Here, X is the ethylene content in mol%.

(2) MFR
According to JIS K7210A method and condition M, measurement was performed under the following conditions. The unit is g / 10 minutes.
Test temperature: 230 ° C., nominal load: 2.16 kg
Die shape: 2.095mm in diameter, 8.000mm in length

(3) Impact resistance At an atmospheric temperature of 23 ° C., an apparatus based on JIS P8134 was used, and the obtained value was used as a measure of the impact resistance of the film. Specifically, a film test piece is fixed to a holder having a diameter of 50 mm, and is struck by a 25.4 mm hemispherical metal penetration, and the work (J) required for penetration failure is measured and divided by the film thickness. And asked.

(4) Heat resistance, sealing property, bending whitening resistance The chill roll surfaces of MD100 mm × TD100 mm films are overlapped so that they are on the outside, and MD2 side and TD1 side are thermocompression bonded with a width of 5 mm (conditions: 200 ° C., 2 kg) / Cm ² , 1.0 second).
Next, 50 ml of tap water was filled from the opening, the air was removed, and the opening was thermocompression bonded under the above conditions, followed by a retort treatment at 135 ° C. for 60 minutes.
After the retort treatment, the water filled bag was checked for partial fusion or deformation, or for water leakage from the seal portion.
Moreover, about the water filling bag in which abnormality was not seen, after leaving at 23 degreeC for 1 day, the inside of four seal parts was bent 180 degree up and down 5 times, respectively, and the presence or absence of whitening of the fold was confirmed.

(5) Deformability Workability A film made of the resin composition of the present invention is used as a sealant, a soft aluminum foil having a chemical conversion treatment on both sides having a thickness of 40 μm is used as an intermediate substrate, and a biaxially stretched nylon film having a thickness of 25 μm is used as a base. Using a two-component curable urethane resin solution adhesive as a material, dry lamination was performed to obtain a three-layer laminate film.
After aging the obtained laminate film at 60 ° C. for 3 days, the laminate film was cut into a strip shape of MD120 mm × TD100 mm, and a rectangular shape with a depth of 5 mm so that the longitudinal direction was MD in the central portion. A recess was formed.
The concave portion is formed by using a punch having a shape of 40 mm × 30 mm, a punch corner radius of 1.5 mm, a punch shoulder radius of 0.75 mm, and a die shoulder radius of 0.75 mm, and a cold deep drawing with a stroke speed of 5 mm / sec. Performed by molding.
For the evaluation of deformation processability, drawing with a depth of 5 mm was performed on 10 laminate films, and all of them were visually observed by light transmission. Evaluation was performed according to the following criteria.
○: No pinhole or cracking was confirmed, and no whitening was observed.
Δ: Pinholes and cracking are not confirmed, but whitening is observed.
X: Pinholes and cracking are confirmed.

(6) Seal strength A laminate film produced in the same manner as above was cut into a strip of 180 mm (MD direction) × 80 mm (TD direction), and this was folded in half in the TD direction with the sealant surface inside, and 20 mm from the crease. The two sides facing each other at the position of No. 5 were thermocompression-bonded at a width of 5 mm (conditions: 220 ° C., 2 kg / cm ² , 2.0 seconds).
The obtained partially fused sample is cut into a strip shape so that the TD is 15 mm wide, and this is pulled at a rate of 300 mm / min with a shopper type tensile tester (manufactured by Tester Sangyo Co., Ltd.), and the heat-sealed portion is peeled off. The force possessed by this was measured and used as the seal strength. The unit is N / 15 mm width.

[Production example]
1. Analysis of Catalyst Composition In the following production examples, analysis of the catalyst composition was performed as follows.
(1) Ti content:
The sample was accurately weighed, hydrolyzed, and measured using a colorimetric method. About the sample after prepolymerization, content was calculated using the weight remove | excluding prepolymerized polymer.
(2) Silicon compound content:
The sample was accurately weighed and decomposed with methanol. The silicon compound concentration in the obtained methanol solution was determined by comparison with a standard sample using gas chromatography.
The content of the silicon compound contained in the sample was calculated from the concentration of the silicon compound in methanol and the weight of the sample. About the sample after prepolymerization, content was calculated using the weight remove | excluding prepolymerized polymer.

2. Preparation of prepolymerization catalyst (1) Preparation of solid component A 10 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 2 L of purified toluene was introduced. Here, 200 g of Mg (OEt) ₂ was added at room temperature, and 1 L of TiCl ₄ was slowly added thereto. The temperature was raised to 90 ° C. and 50 ml of di-n-butyl phthalate was introduced. Thereafter, the temperature was raised to 110 ° C. to carry out a reaction for 3 hours. The reaction product was thoroughly washed with purified toluene.
Subsequently, the refined toluene was introduce | transduced and the whole liquid quantity was adjusted to 2L. 1 L of TiCl ₄ was added at room temperature, the temperature was raised to 110 ° C., and the reaction was performed for 2 hours. The reaction product was thoroughly washed with purified toluene. Subsequently, the refined toluene was introduce | transduced and the whole liquid quantity was adjusted to 2L. 1 L of TiCl ₄ was added at room temperature, the temperature was raised to 110 ° C., and the reaction was performed for 2 hours. The reaction product was thoroughly washed with purified toluene. Furthermore, using purified n-heptane, toluene was replaced with n-heptane to obtain a solid component slurry.
A portion of this slurry was sampled and dried. As a result of analysis, the Ti content of the solid component was 2.7 wt%.
Next, a 20 L autoclave equipped with a stirrer was sufficiently replaced with nitrogen, and 100 g of the solid component slurry was introduced as a solid component. Purified n-heptane was introduced to adjust the solid component concentration to 25 g / L. 50 ml of SiCl ₄ was added and a reaction was performed at 90 ° C. for 1 hr. The reaction product was thoroughly washed with purified n-heptane.
Thereafter, purified n-heptane was introduced to adjust the liquid level to 4 L. To this, 30 ml of dimethyldivinylsilane, 30 ml of i-Pr ₂ Si (OMe) ₂ and 80 g of Et ₃ Al in an n-heptane diluted solution of Et ₃ Al were added and reacted at 40 ° C. for 2 hours. The reaction product was thoroughly washed with purified n-heptane to obtain a solid catalyst.
A portion of the resulting solid catalyst slurry was sampled and dried for analysis. The solid catalyst contained 1.2 wt% Ti and 8.9 wt% i-Pr ₂ Si (OMe) ₂ .

(2) Prepolymerization Prepolymerization was performed by the following procedure using the solid catalyst obtained above.
Purified n-heptane was introduced into the slurry, and the solid catalyst concentration was adjusted to 20 g / L. After cooling the slurry to 10 ° C., 10 g was added n- heptane dilution of _Et 3 Al as _Et 3 Al, were fed over 4hr of propylene 280 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 prepolymerized catalyst.
This prepolymerized catalyst contained 2.5 g of polypropylene per gram of solid catalyst. As a result of analysis, the portion of the prepolymerization catalyst excluding polypropylene contained 1.0 wt% Ti and 8.3 wt% i-Pr ₂ Si (OMe) ₂ .

  Using this prepolymerized catalyst, a propylene-ethylene block copolymer (A) was produced according to the following procedure.

3. Production of Propylene-Ethylene Block Copolymer (A) [Production Example A-1]
A propylene-ethylene block copolymer was produced using a two-tank continuous polymerization facility in which two fluidized bed polymerization tanks having an internal volume of 2 m ³ were connected in series.
Propylene, ethylene, hydrogen, and nitrogen used were purified using a general purification catalyst. The production amount of the propylene-based polymer component (A1) in the first polymerization tank and the production amount of the propylene-ethylene random copolymer component (A2) in the second polymerization tank are the heat exchange used for temperature control of the polymerization tank. It was obtained from the value of the cooling water temperature of the vessel.

(1) Polymerization step (i): Production of propylene polymer component (A1) Propylene homopolymerization was carried out using the first polymerization tank. The polymerization temperature was 65 ° C., the total pressure was 3.0 MPaG, and the powder hold amount was 40 kg. Propylene, hydrogen, and nitrogen were continuously supplied to the polymerization tank, and the concentrations of propylene and hydrogen were adjusted to 70.83 mol% and 0.49 mol%, respectively. As a cocatalyst, Et ₃ Al was continuously supplied at a rate of 5.0 g / h. The prepolymerized catalyst obtained above was continuously supplied to the polymerization tank so that the production amount of the propylene polymer component (A1) in the first polymerization tank was 20.0 kg / h. The produced propylene polymer component (A1) was continuously extracted and adjusted so that the powder hold amount was constant at 40 kg. The propylene polymer component (A1) extracted from the first polymerization tank was continuously supplied to the second polymerization tank, and the production of the propylene-ethylene random copolymer component (A2) was continued.
When a part of the propylene polymer component (A1) produced in the first polymerization tank was extracted and analyzed, the MFR (A1) was 3.90 g / 10 min. Further, when the catalytic activity was calculated from the value obtained by dividing the production amount of the propylene-based polymer component (A1) by the amount of catalyst supplied (excluding polypropylene contained in the prepolymerized catalyst), the catalytic activity in the polymerization step (i) was calculated. Was 22 kg-PP / g-catalyst.

(2) Polymerization step (ii): Production of propylene-ethylene random copolymer component (A2) Random copolymerization of propylene and ethylene was performed using a second polymerization tank. The polymerization temperature was 65 ° C., the total pressure was 2.0 MPaG, and the powder hold amount was 40 kg. Propylene, ethylene, hydrogen, and nitrogen were continuously supplied to the polymerization tank, and the concentrations of propylene, ethylene, and hydrogen were adjusted to 62.00 mol%, 9.43 mol%, and 3.57 mol%, respectively. . By continuously supplying ethanol as a polymerization inhibitor, the production amount of the propylene-ethylene random copolymer component (A2) in the second polymerization tank was adjusted to 5.0 kg / h. The propylene-ethylene block copolymer (A) thus produced was continuously extracted and adjusted so that the powder hold amount was constant at 40 kg. The propylene-ethylene block copolymer (A) extracted from the second polymerization tank was further transferred to a drier and sufficiently dried.
When a part of the produced propylene-ethylene block copolymer (A) was analyzed, MFR (A) was 3.80 g / 10 min and ethylene content E (A) was 4.6 wt%. From the production amount of the polymerization step (i) and the production amount of the polymerization step (ii), the weight ratio W (A1) of the propylene polymer component (A1) and the weight ratio W of the propylene-ethylene random copolymer component (A2). When (A2) was determined, they were 0.80 and 0.20, respectively.

From the W (A1), W (A2), E (A), MFR (A1), and MFR (A) thus obtained, the ethylene content E (A2) and MFR of the propylene-ethylene random copolymer component (A2). (A2) was calculated. The following formula was used for the calculation.
E (A2) = {E (A) −E (A1) × W (A1)} ÷ W (A2)
MFR (A2) = exp {(log _e [MFR (A)] − W (A1) × log _e [MFR (A1)]) ÷ W (A2)}
(Here, since the propylene polymer component (A1) is a propylene homopolymer, E (A1) is 0 wt%. The above two formulas are those described in the above paragraphs [0035] and [0037]. Are rearranged for E (A2) and MFR (A2).)
The ethylene content [E (A2)] was 23.0 wt%, and the MFR (A2) was 3.42 g / 10 min.

[Production Examples A-2 and A-11]
A propylene-ethylene block copolymer (A) was produced in the same manner as in Production Example A-1, except that the conditions shown in Table 2 were used. At this time, random copolymerization of propylene and ethylene is performed by continuously supplying ethylene to the first polymerization tank. The results are shown in Table 2.

[Production Examples A-3 to A-10]
A propylene-ethylene block copolymer (A) was produced in the same manner as in Production Example A-1, except that the conditions shown in Table 2 were used. The results are shown in Table 2.

[Examples 1-6 and Comparative Examples 1-6]
Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane 0.05 parts by weight with respect to 100 parts by weight of the propylene-ethylene block copolymer (A), Tris (2,4-di-t-butylphenyl) phosphite 0.05 parts by weight, calcium stearate 0.05 parts by weight, and in Example 6, 0.20 part by weight of erucic acid amide was further added, Each was mixed and homogenized with a tumbler, and the resulting mixture was melt-kneaded at 230 ° C. with a 35 mm diameter twin-screw extruder and pelletized. The kneading conditions are shown below.
Using this pellet, it was melt extruded at 230 ° C. with a 35 mm diameter extruder having a T-shaped die having a width of 330 mm, and then cooled and solidified while being wound around a chill roll having a diameter of 300 mm adjusted to 30 ° C., and a film thickness of 30 μm. An unstretched battery packaging sealant film was obtained. The film forming specifications are shown below.
The physical properties of the obtained film were measured according to the measurement method. Table 3 shows the evaluation results.

(Kneading conditions)
Kneading machine: 35mm diameter same direction biaxial kneading machine manufactured by Toshiba Machine Co., Ltd. Kneading temperature: 230 ° C
Screw rotation speed: 250rpm
Feeder rotation speed: 50 rpm
(Film forming)
T-die molding machine: 35 mm diameter single-axis molding machine manufactured by Plako Corporation Extrusion temperature: 240 ° C
Chill roll temperature: 35 ° C
Drawing speed: 18.0 to 20.0 m / min Film thickness: around 30 μm

[Examples 7 and 8]
In Examples 7 and 8, the following ER-1 and ER-2 were used as the ethylene-α-olefin copolymer elastomer.
ER-1: manufactured by Mitsui Chemicals, Toughmer A4085S
[Density: 0.886 g / cm ³ , MFR (190 ° C.): 3.6 g / 10 min]
ER-2: Kernel KS340T manufactured by Japan Polyethylene Corporation
[Density: 0.880 g / cm ³ , MFR (190 ° C.): 3.5 g / 10 min]

Each pellet of the composition containing the propylene-ethylene block copolymer (A) of Examples 7 and 8 obtained in the same manner as in Example 6 above was added to 100 parts by weight of the propylene-ethylene block copolymer (A). Then, ER-1 or ER-2 was added so as to have a ratio of 10 parts by weight, and ER-1 or ER-2 was mixed so as to be uniform, and then 330 mm as in Example 6 and the like. A melt-extruded battery packaging sealant with a film thickness of 30 μm is melt-extruded at 250 ° C. with a 35 mm diameter extruder having a T-shaped die and then cooled and solidified while being wound around a chill roll with a diameter of 300 mm adjusted to 40 ° C. A film was obtained.
The physical properties of the obtained film were measured according to the measurement method. Table 3 shows the evaluation results.

[Consideration of results of Examples and Comparative Examples]
As is apparent from Table 3, the film made of the propylene-ethylene block copolymer (A) according to the present invention is not limited to heat resistance, sealing performance, bending whitening resistance, and deformability, but also impact resistance. And excellent sealing strength characteristics (Examples 1 to 8).
On the other hand, the film which consists of a propylene-ethylene block copolymer which does not satisfy | fill the requirements of this invention cannot satisfy each evaluation item with sufficient balance, and is not suitable as a sealant film for battery packaging (Comparative Examples 1-6).
From the above results, in each example of the present invention, each performance of the sealant film for battery packaging is well-balanced and, in general, remarkably superior compared to each comparative example, and the rationality and significance of the configuration of the present invention are significant. And excellence over the prior art.

  The polypropylene resin composition of the present invention not only has excellent heat resistance, sealing properties, and moldability, but also has high sealing strength and impact resistance, and is excellent in whitening resistance and cracking resistance during deformation processing. In other words, it excels also in the moldability after film and laminating processing required as a sealant for battery packaging materials, and the prevention of leakage of contents at normal and abnormally high temperatures, and is effective as a sealant material for battery packaging. Can be used.

Claims (6)

A propylene-ethylene block copolymer (A) containing a propylene-based polymer component (A1) and a propylene-ethylene random copolymer component (A2) satisfying the following conditions (a1) to (a4) obtained by multistage polymerization: A polypropylene resin composition for battery packaging films.
-Propylene-ethylene block copolymer (A);
(A1) The propylene polymer component (A1) is a propylene homopolymer or copolymer having an ethylene content of 0 to 2% by weight.
(A2) The MFR (230 ° C., 2.16 kg load) of the propylene-based polymer component (A1) is 1.0 to 10 g / 10 min.
(A3) The propylene-ethylene random copolymer component (A2) has an ethylene content of 10 to 40% by weight.
(A4) The MFR (230 ° C., 2.16 kg load) of the propylene-ethylene random copolymer component (A2) is 0.5 to 5 g / 10 minutes.   The weight ratio W (A1) of the propylene-based polymer component (A1) in the propylene-ethylene block copolymer (A) is 60 to 95% by weight, and the weight ratio W (A2) of the propylene-ethylene random copolymer component (A2). The polypropylene resin composition for battery packaging film according to claim 1, wherein the composition is 5 to 40% by weight. Furthermore, lubricants fatty acid amide-based, propylene - ethylene block copolymer (A) with respect to 100 parts by weight, according to claim 1 or 2, characterized in that it contains 0.03 to 0.5 parts by weight Polypropylene resin composition for battery packaging film. A single-layer sealant film obtained by melt-extrusion film formation of the polypropylene resin composition for battery packaging film according to any one of claims 1 to 3 . A multilayer sealant film obtained by melt extrusion film formation using the polypropylene resin composition for battery packaging film according to any one of claims 1 to 3 as at least one side layer of both outer layers. A film comprising the single-layer or multilayer sealant film according to claim 4 or 5 as a sealant for battery packaging materials.