JP5604336B2 - Sealing material - Google Patents

Description

  The present invention relates to a sealing material, and more particularly to a low-eluting sealing material excellent in flexibility and heat resistance.

Conventionally, as sealing materials used as lid materials for various containers, etc., silicone rubber, butyl rubber, styrene elastomer, low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer resin, or a blend thereof Materials are used. The sealing material is required to have a certain degree of flexibility in order to maintain hermeticity, but there is a problem that gas barrier properties, heat resistance, elution properties, and the like deteriorate.
Specific examples of the sealing material include a cap liner material, a container stopper, and a syringe gasket. In recent years, a high level of safety and hygiene is required in these food applications, medical applications, and hygiene applications. In these applications, high-temperature sterilization may be performed, and low elution is required. Therefore, there is a demand for a sealing material that is flexible, heat resistant, and has low elution properties.

Propylene-based polymers are used in various applications, taking advantage of their excellent safety and hygiene, molding processability, mechanical properties, and barrier properties. It was hardly used for the required sealing material application.
In Patent Document 1, a gasket for molding a plastic lens is proposed, and a water obtained by hydrogenating a block copolymer having a polymer block mainly composed of a vinyl aromatic compound and a polymer block mainly composed of a conjugated diene compound. It has been proposed to use a material added with a block copolymer as a gasket. Patent Document 2 proposes that a composition obtained by kneading a hydrogenated styrene-conjugated diene block copolymer rubber and polybutene in polypropylene resin is used for a cap liner at the mouth of a bottle. However, with such materials, there is a concern of the dissolution of the blended components.

JP 2009-226864 A JP 2010-2222032 A

Thus, in sealing materials, low-elution sealing materials with excellent flexibility and heat resistance are required, with excellent flexibility, heat resistance, low elution properties, and requirements for appropriate hardness, transparency, etc. Although it is necessary to satisfy all the performances, it is very difficult to achieve this as long as the existing polyolefin resin material is used.
An object of the present invention is to provide a low-elution sealing material that improves these performances in a balanced manner and is excellent in flexibility and heat resistance.

  As a result of intensive studies to solve the above problems, the present inventor has found that a low-elution sealing material excellent in flexibility and heat resistance can be obtained by using a specific propylene polymer material. The present invention has been completed.

That is, according to the first aspect of the present invention, the following components (A) 30 to 70 wt% and the following components (B) 70 to 30 seen containing a wt%, further component (C) a propylene -α- olefin random The copolymer or ethylene-α-olefin random copolymer is made of a polypropylene resin material containing 1 to 100 parts by weight with respect to 100 parts by weight of the total amount of the component (A) and the component (B). A sealing material is provided.
Component (A): a propylene polymer satisfying the following conditions (a1) to (a3).
(A1) Melting peak temperature (Tm) measured by DSC method is 125 to 155 ° C.
(A2) The content of a comonomer selected from ethylene and an α-olefin having 4 or more carbon atoms is 0 to 5% by weight.
(A3) Molecular weight distribution (Mw / Mn) measured by GPC method is 1.5-4
Component (B): a propylene-ethylene random copolymer having an ethylene content of 3 to 25% by weight, obtained using a metallocene catalyst.

  According to the second invention of the present invention, in the first invention, the composition of component (A) and component (B) is a temperature-loss tangent curve obtained by solid viscoelasticity measurement (DMA). There is provided a sealing material characterized in that the tan δ curve has a single peak at 0 ° C. or lower.

  According to the third invention of the present invention, in the first or second invention, the polypropylene resin material has a melt flow rate (MFR: 230 ° C. 2.16 kg) of 0.5 to 100 g / 10 min, a melting peak. A sealing material characterized in that the temperature (Tm) is 110 to 155 ° C. and the molecular weight distribution (Mw / Mn) is 1.5 to 4 is provided.

  According to the fourth aspect of the present invention, in any one of the first to third aspects, the ethylene content (% by weight) of the component (B) is equal to the comonomer content (% by weight) of the component (A). 3) to 20% by weight is provided.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the polypropylene resin material is obtained by melt blending the component (A) and the component (B). The sealing material characterized by this is provided.

  According to the sixth aspect of the present invention, in any one of the first to fourth aspects, the polypropylene resin material is obtained by sequentially polymerizing the component (A) and the component (B). The sealing material characterized by this is provided.

  The sealing material of the present invention provides a sealing material that is excellent in flexibility, heat resistance, low elution with few elution components, has excellent hardness and transparency, and can pass the Japanese Pharmacopoeia test. can do.

The present invention is a low-elution sealing material comprising a polypropylene resin material containing 30 to 70% by weight of the following component (A) and 70 to 30% by weight of the following component (B).
Component (A): a propylene polymer satisfying the following conditions (a1) to (a3).
(A1) Melting peak temperature (Tm) measured by DSC method is 125 to 155 ° C.
(A2) The content of a comonomer selected from ethylene and an α-olefin having 4 or more carbon atoms is 0 to 5% by weight.
(A3) Molecular weight distribution (Mw / Mn) measured by GPC method is 1.5-4
Component (B): a propylene-ethylene random copolymer having an ethylene content of 3 to 25% by weight, obtained using a metallocene catalyst.
Hereinafter, each component, its production method and the like will be described in detail.

The component (A) used for the sealing material of the present invention is a propylene polymer and needs to satisfy the following (a1) to (a3).
(A1) Melting peak temperature (Tm) measured by DSC method is 125 to 155 ° C.
(A2) The content of a comonomer selected from ethylene and an α-olefin having 4 or more carbon atoms is 0 to 5% by weight.
(A3) Molecular weight distribution (Mw / Mn) measured by GPC method is 1.5-4

Hereinafter, the above (a1) to (a3) will be described.
(A1) Melting peak temperature (Tm)
The melting peak temperature (Tm) measured by the differential scanning calorimeter (DSC) of the propylene polymer (component (A)) needs to be in the range of 125 to 155 ° C, and preferably 127 to 150 ° C. More preferably, it is 130-140 degreeC. When Tm is less than 125 ° C, the heat resistance is deteriorated, and when it exceeds 155 ° C, the flexibility is deteriorated. In addition, in order to adjust melting peak temperature (Tm), it can adjust easily by controlling the quantity of ethylene supplied to a polymerization reaction system.
Here, the specific measurement of Tm is performed using a differential scanning calorimeter (DSC), taking a sample amount of 5 mg, holding at 200 ° C. for 5 minutes, and then crystallizing to 40 ° C. at a rate of temperature decrease of 10 ° C./min. Further, the peak position of the curve drawn when the film is melted at a temperature rising rate of 10 ° C./min is defined as a melting peak temperature Tm (° C.).

(A2) Content of comonomer The content of a comonomer selected from ethylene and an α-olefin having 4 or more carbon atoms in the propylene polymer (component (A)) is 0 to 5% by weight.
The α-olefin having 4 or more carbon atoms is preferably an α-olefin having 4 to 12 carbon atoms, and 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene and the like can be preferably exemplified. . As the α-olefin for copolymerization, ethylene, 1-butene, 1-hexene and 1-octene are particularly preferable. Examples of the copolymer include propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-hexene-1 copolymer, propylene-octene-1 copolymer, propylene-ethylene-butene-1 copolymer Binary or ternary copolymers in which some amount of comonomer is arbitrarily combined, such as polymer, propylene-ethylene-hexene-1 copolymer, propylene-butene-1-octene-1 copolymer, etc. Can be illustrated.

  The content of the α-olefin for copolymerization (including ethylene) may be 0% by weight, that is, a propylene homopolymer, and at most 5% by weight. When it exceeds 5% by weight, the elution property is deteriorated. The content of the α-olefin for copolymerization is preferably 4% by weight or less, more preferably less than 3% by weight, and further preferably 2% by weight or less. By setting it as such a range, melting peak temperature (Tm) becomes the range of 125-155 degreeC, and heat resistance becomes favorable.

(A3) Molecular weight distribution (Mw / Mn)
The molecular weight distribution (Mw / Mn) of the propylene polymer (component (A)) measured by the rupermeation (GPC) method needs to be in the range of 1.5 to 4, and is 1.8 or more and 3 or less. Preferably there is. If the Mw / Mn is less than 1.5, it is difficult to obtain with the current polymerization technique, and if it exceeds 4, the sealing material may become sticky.
The method of adjusting the molecular weight distribution can be adjusted by using a metallocene catalyst described later or by polymerizing a propylene (co) polymer and then melt kneading using an organic peroxide. it can. For broadening, it can be adjusted by polymerization using a Ziegler-Natta catalyst, a catalyst system using two or more metallocene catalyst components in combination, or a catalyst system using two or more metallocene complexes.

Here, the molecular weight distribution is obtained by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn), and is obtained by measurement by a gel permeation chromatography (GPC) method.
Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene.
The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A calibration curve is prepared by injecting 0.2 ml of a solution dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) so that each is 0.5 mg / ml.
The calibration curve uses a cubic equation obtained by approximation by the least square method. The following numerical value is used for [η] = K × Mα in the viscosity formula used for conversion to molecular weight.
PS: K = 1.38 × 10 ⁻⁴ α = 0.7
PP: K = 1.03 × 10 ⁻⁴ α = 0.78

The measurement conditions for GPC are as follows.
Apparatus: GPC manufactured by WATERS (ALC / GPC 150C)
Detector:
MIRAN 1A IR detector manufactured by FOXBORO (measurement wavelength: 3.42 μm)
Column: AD806M / S (3 pieces) manufactured by Showa Denko KK
Mobile phase solvent: o-dichlorobenzene Measurement temperature: 140 ° C.
Flow rate: 1.0 ml / min Injection volume: 0.2 ml
Sample preparation: Prepare a 1 mg / ml solution using o-dichlorobenzene (containing 0.5 mg / ml BHT) and dissolve it at 140 ° C. for about 1 hour.

In order to obtain the propylene polymer (component (A)) used in the present invention, a Ziegler-Natta catalyst or a metallocene catalyst may be used, but a metallocene catalyst is preferably used from the viewpoint of low elution. The metallocene catalyst is not particularly limited, and (i) a group 4 transition metal compound (so-called metallocene compound) containing a ligand having a cyclopentadienyl skeleton and (ii) a metallocene compound reacts with the metallocene catalyst. It is a catalyst comprising a cocatalyst that can be activated to a stable ionic state and, if necessary, (iii) an organoaluminum compound, and any known catalyst can be used. A preferable metallocene catalyst will be described later.
The polymerization process used for obtaining the component (A) is not particularly limited, and a known polymerization process can be used. For example, a slurry polymerization method, a bulk polymerization method, a gas phase polymerization method and the like can be used.

  The other component, component (B), is a propylene-ethylene random copolymer having an ethylene content of 3 to 25% by weight, obtained using a metallocene catalyst. Although there is low elution, the ethylene content is 3 to 25% by weight in order to maintain flexibility. When the ethylene content is less than 3% by weight, the flexibility of the sealing material is deteriorated, and when it exceeds 25% by weight, the elution property is deteriorated. The lower limit of the preferred ethylene content of component (B) is 4% by weight or more, more preferably more than 5% by weight, especially 7% by weight or more, and the preferred lower limit is 23% by weight or less, more preferably 20% by weight. % Or less, in particular 18% by weight or less.

The ethylene content of component (B) is preferably closer to the comonomer content of the propylene polymer (component (A)) in order to increase the compatibility with component (A), but if too high, component (B) A) and component (B) are phase-separated, and the entire composition does not become a uniform and fine dispersion, so that mechanical properties such as flexibility, transparency, etc. may be greatly reduced. is there.
Therefore, the range of the ethylene content of component (B) is preferably 3 to 20% by weight, more preferably 6 to 18% by weight, still more preferably 8 to 16% by weight, compared to the comonomer content of component (A). %.
When the amount is less than 3% by weight, the effect of compatibilization with the component (A) is not sufficient, which is not preferable. On the other hand, when the content exceeds 20% by weight, the compatibility with the component (A) is deteriorated and the entire composition becomes a non-uniform dispersion. As a result, mechanical properties such as flexibility and tensile elongation are significantly reduced. Transparency may also deteriorate.

The catalyst used to obtain the propylene-ethylene random copolymer is a Ziegler-Natta catalyst or a metallocene catalyst, preferably a metallocene catalyst. There is no restriction | limiting in particular as a metallocene catalyst, A well-known thing can be used like the above. A preferable metallocene catalyst will be described later.
The polymerization process used for obtaining the component (A) is not particularly limited, and a known polymerization process can be used. For example, a slurry polymerization method, a bulk polymerization method, a gas phase polymerization method and the like can be used.

The polypropylene resin material constituting the sealing material of the present invention is a material containing 30 to 70% by weight of component (A) and 70 to 30% by weight of component (B).
The component (B) needs to be 30% by weight or more from the viewpoint of flexibility, and 70% by weight or less from the viewpoint of elution. The preferred composition is 35 to 65% by weight of component (A) and 65 to 35% by weight of component (B), more preferably 40 to 60% by weight of component (A) and 60 to 40% by weight of component (B). .

(Melt blend)
The polypropylene resin material used for the sealing material of the present invention can also be produced by melt blending the component (A) and the component (B).
There is no restriction | limiting in the manufacturing method by a melt blend, A well-known method can be employ | adopted widely. Specific examples include component (A) and component (B) according to the present invention, and other components blended as necessary, for example, ribbon blender, Henschel mixer, Banbury mixer, single screw or twin screw Examples thereof include a melt kneading method using an extruder, a kneader and the like.

The method for producing the polypropylene resin material used in the present invention may be the above melt blend, but is preferably obtained by sequentially polymerizing the component (A) and the component (B) from the viewpoint of physical property balance.
The sequential polymerization method is known, and there is no particular limitation as a specific method. After the component (A) is polymerized in an amount of 30 to 70% by weight in the first step, the component (B) is added in an amount of 70 to 70 in the second step. It can be obtained by sequential polymerization of 30% by weight. The polymerization example which uses ethylene as a comonomer of a component (A) below is shown.

(Sequential polymerization)
In the present invention, the polypropylene resin material is a so-called block copolymer in the industry in which components having different ethylene contents are sequentially polymerized in the first step and the second step. It is extremely suitable for balancing impact resistance and heat resistance.
In the present invention, since a copolymer having a low molecular weight and easily sticking alone may be used as the component (B), the component (A) is polymerized in order to prevent problems such as adhesion to the reactor. It is preferable to use a sequential polymerization method in which the component (B) is polymerized.
When performing sequential polymerization, either a batch method or a continuous method can be used, but it is generally desirable to use a continuous method from the viewpoint of productivity.

In the case of a batch method, it is possible to polymerize component (A) and component (B) separately using a single reactor by changing the polymerization conditions with time. As long as the effect of the present invention is not impaired, a plurality of reactors may be connected in parallel.
In the case of a continuous process, since it is necessary to polymerize component (A) and component (B) separately, it is necessary to use a production facility in which two or more reactors are connected in series, but the effect of the present invention is not impaired. As long as each of the component (A) and the component (B) is used, a plurality of reactors may be connected in series and / or in parallel.

(Polymerization process)
As the polymerization process, any polymerization method such as a slurry method, a bulk method, or a gas phase method can be used. Although supercritical conditions can be used as intermediate conditions between the bulk method and the gas phase method, they are substantially the same as the gas phase method, and are therefore included in the gas phase method without particular distinction.
Since component (B) is readily soluble in organic solvents such as hydrocarbons and liquefied propylene, it is desirable to use a gas phase method for the production of component (B). There is no particular problem in using any process for the production of the component (A). However, when producing the component (A) having relatively low crystallinity, a gas phase method is used to avoid problems such as adhesion. It is desirable to use
Therefore, it is most desirable to polymerize component (A) first by the bulk method or gas phase method and then polymerize component (B) by the gas phase method using the continuous method.

(Polymerization conditions)
The polymerization temperature can be used without any particular problem as long as it is in a commonly used temperature range. Specifically, a range of 0 ° C. to 200 ° C., more preferably 40 ° C. to 100 ° C. can be used.
The polymerization pressure varies depending on the process to be selected, but can be applied without any problem as long as it is in a pressure range usually used. Specifically, a range of greater than 0 to 200 MPa, more preferably 0.1 MPa to 50 MPa can be used. At this time, an inert gas such as nitrogen may coexist.

  When the component (A) is sequentially polymerized in the first step and the component (B) is sequentially polymerized in the second step, it is desirable to add a polymerization inhibitor to the system in the second step. When a polymerization inhibitor is added to the reactor for carrying out the second step propylene-ethylene random copolymerization, the product quality such as particle properties (fluidity, etc.) and gel of the resulting powder can be improved. Various technical studies have been made on this method, and examples thereof include Japanese Patent Publication No. 63-54296, Japanese Patent Application Laid-Open No. 7-25960, Japanese Patent Application Laid-Open No. 2003-2939, and the like. It is desirable to apply the method to the present invention.

(Control method of each component in sequential polymerization)
Component (A), component (B), and each element in the case of sequential polymerization are controlled as follows, and can be manufactured so as to satisfy the constituent requirements required for the polypropylene resin material of the present invention.

(Ingredient (A))
About a component (A), it is necessary to control the ethylene content (henceforth [E] A) and melting peak temperature (henceforth Tm (A)).
[E] In order to control A within a predetermined range, the amount ratio of propylene and ethylene supplied to the polymerization tank in the first step may be appropriately adjusted. The relationship between the supply ratio and the ethylene content in the resulting propylene-ethylene random copolymer varies depending on the type of metallocene catalyst used, but the component having the required ethylene content [E] A by adjusting the supply ratio ( A) can be produced.
[E] In order to control A to 5% by weight or less, the supply ratio by weight of ethylene to propylene may be 0.3 or less, preferably 0.2 or less.
At this time, the component (A) has a narrow crystallinity distribution, and Tm (A) decreases as [E] A increases.
Therefore, in order for Tm (A) to satisfy the scope of the present invention, [E] A and the relationship between these are grasped and adjusted to take the target range.
The molecular weight distribution Mw / Mn of the component (A) can be adjusted by selecting a catalyst type or expanding the distribution by using a Ziegler-Natta catalyst or a catalyst system using two or more metallocene catalyst components in combination. It can be controlled by performing polymerization using two or more stages during polymerization.

(Ingredient (B))
About a component (B), it is necessary to control the ethylene content (henceforth [E] B).
In order to control [E] B within a predetermined range, the ratio of ethylene supply to propylene in the second step may be controlled as in [E] A. [E] When controlling B to 3 to 25% by weight, the supply weight ratio of ethylene to propylene may be in the range of 0.005 to 6, preferably in the range of 0.01 to 3.
In addition, the identification method of ethylene content is well-known, and follows the method as described in paragraph [0045] below of Unexamined-Japanese-Patent No. 2010-121126.

(Amount of component (A) and amount of component (B))
The amount of component (A) (hereinafter also referred to as W (A)) and the amount of component (B) (hereinafter also referred to as W (B)) are the production amounts of the first step for producing component (A). And the ratio of the production amount of the component (B) can be controlled. For example, in order to increase W (A) and decrease W (B), the production amount of the second step may be reduced while maintaining the production amount of the first step, which shortens the residence time of the second step. It can be easily controlled by lowering the polymerization temperature or increasing the amount of the polymerization inhibitor. The reverse is also true.
When actually setting the conditions, it is necessary to consider the activity decay. That is, depending on the range of ethylene content [E] A and [E] B, generally, when the ratio of ethylene supply to propylene is increased in order to increase the ethylene content, the polymerization activity tends to increase, and at the same time the activity decay tends to increase. It is in. Therefore, in order to maintain the activity of the second step, it is necessary to suppress the polymerization activity of the first step. Specifically, in the first step, the ethylene content [E] A is lowered and the production amount W (A ), And if necessary, lower the polymerization temperature and / or shorten the polymerization time (residence time), or increase the ethylene content [E] B in the second step and increase the production W (B). If necessary, the conditions may be set by a method that raises the polymerization temperature and / or lengthens the polymerization time (residence time).

(Metallocene catalyst)
The method for producing the component (B) requires the use of a metallocene catalyst.
In the propylene-ethylene random copolymer, when the molecular weight and the crystallinity distribution are wide, it is well known to those skilled in the art that the stickiness and bleedout deteriorate, but also in the present invention, in order to suppress the stickiness and bleedout, It is necessary to polymerize using a metallocene-based catalyst that narrows the molecular weight and crystallinity distribution in component (B).

The type of the metallocene-based catalyst is not particularly limited as long as a polymer having the performance of the present invention can be produced. In order to satisfy the requirements of the present invention, for example, the components (a ), (B) and, if necessary, a metallocene catalyst comprising component (c) is preferably used.
Component (a): at least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula (1) Component (b): from the following (b-1) to (b-4) At least one selected solid component (b-1) A particulate carrier on which an organoaluminoxy compound is supported (b-2) The component (a) can be converted into a cation by reacting with the component (a) Fine carrier on which ionic compound or Lewis acid is supported (b-3) Solid acid fine particle (b-4) Ion exchange layered silicate / Component (c): Organoaluminum compound

(Component (a))
As the component (a), at least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula (1) can be used.
^{_{Q (C 5 H 4 -aR 1}} ) (C 5 H 4 -bR 2) MeXY ··· (1)
[In the formula (1), Q represents a divalent linking group that bridges two conjugated five-membered ring ligands, Me represents a metal atom selected from titanium, zirconium, and hafnium, and X and Y represent Each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group or a silicon-containing hydrocarbon group.
R ¹ and R ² are hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group. Show. a and b are the number of substituents. ]

Specifically, Q represents a divalent linking group that bridges two conjugated five-membered ring ligands. For example, a divalent hydrocarbon group, a silylene group, an oligosilylene group, or a hydrocarbon group as a substituent. Examples thereof include a silylene group or an oligosilylene group, or a germylene group having a hydrocarbon group as a substituent. Among these, a silylene group having a divalent hydrocarbon group and a hydrocarbon group as substituents is preferable.
X and Y represent a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, or a silicon-containing hydrocarbon group. Among these, hydrogen is preferable , Chlorine, methyl, isobutyl, phenyl, dimethylamide, diethylamide group and the like. X and Y may be independent, that is, may be the same or different.

R ¹ and R ² are hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing carbon group. Represents a hydrogen group. Specific examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a phenyl group, a naphthyl group, a butenyl group, and a butadienyl group. In addition, as halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group, methoxy group, ethoxy group, phenoxy group Typical examples include trimethylsilyl group, diethylamino group, diphenylamino group, pyrazolyl group, indolyl group, dimethylphosphino group, diphenylphosphino group, diphenylboron group, and dimethoxyboron group.
In these, it is preferable that it is a C1-C20 hydrocarbon group, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, and a butyl group. By the way, adjacent R ¹ and R ² may combine to form a ring, on which a hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing You may have a substituent which consists of a hydrocarbon group, a boron containing hydrocarbon group, or a phosphorus containing hydrocarbon group.
Me is a metal atom selected from titanium, zirconium and hafnium, preferably zirconium and hafnium.

  Among the components (a) described above, preferred for producing the components (A) and (B) contained in the polypropylene resin material are a silylene group, a germylene group or an alkylene having a hydrocarbon substituent. A transition metal compound comprising a ligand having a substituted cyclopentadienyl group, a substituted indenyl group, a substituted fluorenyl group or a substituted azulenyl group, and a silylene group having a hydrocarbon substituent, It is a transition metal compound composed of a ligand having a 2,4-position substituted indenyl group and a 2,4-position substituted azulenyl group, which is crosslinked with a germylene group.

  Non-limiting specific examples of such preferred transition metal compounds include dimethylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride, diphenylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride. Dimethylsilylene bis (2-methylbenzoindenyl) zirconium dichloride, dimethylsilylene bis {2-isopropyl-4- (3,5-diisopropylphenyl) indenyl} zirconium dichloride, dimethylsilylene bis (2-propyl-4-phenane) Tolylindenyl) zirconium dichloride, dimethylsilylenebis (2-methyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) azurenyl} zirconi Mudichloride, dimethylsilylenebis (2-ethyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis (2-isopropyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis {2-ethyl-4- (2-fluoro) Biphenyl) azurenyl} zirconium dichloride, dimethylsilylenebis {2-ethyl-4- (4-tert-butyl-3-chlorophenyl) azurenyl} zirconium dichloride, and the like. In these specific examples, a compound in which a silylene group is replaced with a germylene group and zirconium is replaced with hafnium is also exemplified as a suitable compound. In addition, since the catalyst component is not an important element of the present invention, it avoids complicated listing and is limited to a representative example, but it is obvious that the effective range of the present invention is not limited by this. It is.

(Component (b))
As the component (b), at least one solid component selected from the components (b-1) to (b-4) is used. Each of these components is a known component, and can be appropriately selected from known technologies and used.
Examples of the particulate carrier used for the component (b-1) and the component (b-2) include inorganic oxides such as silica, alumina, magnesia, silica alumina, and silica magnesia, magnesium chloride, magnesium oxychloride, aluminum chloride, and chloride. Examples thereof include inorganic halides such as lanthanum, and porous organic carriers such as polypropylene, polyethylene, polystyrene, styrene divinyl benzene copolymer, and acrylic acid copolymer.

Further, as a non-limiting specific example of the component (b), as the component (b-1), a particulate carrier on which methylalumoxane, isobutylalumoxane, methylisobutylalumoxane, aluminum butylboronate tetraisobutyl and the like are supported As component (b-2), triphenylborane, tris (3,5-difluorophenyl) borane, tris (pentafluorophenyl) borane, triphenylcarbonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl Particulate carrier carrying anilinium tetrakis (pentafluorophenyl) borate, etc., component (b-3), alumina, silica alumina, magnesium chloride, etc., component (b-4), montmorillonite, zakonite, beidellite , Nontronic , Saponite, hectorite, stevensite, bentonite, smectite group such as taeniolite, vermiculite, and the like mica group. These may form a mixed layer.
Particularly preferred among the above components (b) is the ion-exchange layered silicate of component (b-4), and more preferred are chemical treatments such as acid treatment, alkali treatment, salt treatment, and organic matter treatment. It is an ion exchange layered silicate applied.

(Component (c))
If necessary, an example of the organoaluminum compound used as the component (c) is an organoaluminum compound represented by the following general formula (2).
General formula AlR _a P _3-a (2)
(Wherein R is a hydrocarbon group having 1 to 20 carbon atoms, P is hydrogen, halogen, alkoxy group, a is a number of 0 <a ≦ 3), trimethylaluminum, triethylaluminum, tripropylaluminum, tri Trialkylaluminum such as isobutylaluminum or halogen or alkoxy-containing alkylaluminum such as diethylaluminum monochloride, diethylaluminum monomethoxide. In addition, aluminoxanes such as methylaluminoxane can also be used. Of these, trialkylaluminum is particularly preferred.

(Catalyst formation)
The component (a), the component (b) and, if necessary, the component (c) are brought into contact to form a catalyst. Although the contact method is not specifically limited, it can contact in the order which exists in the following 1) -5). Moreover, this contact may be performed not only at the time of catalyst preparation but also at the time of prepolymerization with olefin or at the time of polymerization of olefin.
1) Contact component (a) and component (b) 2) Add component (c) after contacting component (a) and component (b) 3) Contact component (a) and component (c) 4) Add component (a) after contacting component (b) and component (c) 5) Contact three components simultaneously

The amount of components (a), (b) and (c) used is arbitrary. For example, the amount of component (a) used relative to component (b) is preferably in the range of 0.1 μmol to 1,000 μmol, particularly preferably 0.5 μmol to 500 μmol, relative to 1 g of component (b). The amount of component (c) used relative to component (b) is preferably such that the amount of transition metal is 0.001 to 100 μmol, particularly preferably 0.005 to 50 μmol, relative to 1 g of component (b). Therefore, the amount of the component (c) to the component (a) is preferably in the range of 10 ⁻⁵ to 50, particularly preferably 10 ^{−4 to} 5 in terms of the molar ratio of the transition metal.

The catalyst is preferably subjected to a so-called prepolymerization treatment in which a small amount of polymer is brought into contact with an olefin in advance. The olefin used for the prepolymerization is not particularly limited, but ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, Styrene and the like can be used, and it is particularly preferable to use propylene. The olefin can be supplied by any method, such as a supply method for maintaining the olefin at a constant speed or in a constant pressure state, a combination thereof, or a stepwise change.
The prepolymerization temperature and time are not particularly limited, but are preferably in the range of −20 ° C. to 100 ° C. and 5 minutes to 24 hours, respectively. The prepolymerization amount is preferably 0.01 to 100 times, more preferably 0.1 to 50 times in terms of weight ratio of the prepolymerized polymer to the component (b). After completion of the prepolymerization, the catalyst can be used as it is, depending on the usage form of the catalyst. However, if necessary, drying can be performed.
Furthermore, a polymer such as polyethylene, polypropylene, or polystyrene, or an inorganic oxide solid such as silica or titania can be allowed to coexist during or after the contact of the above components.

(Tan δ curve peak of polypropylene resin material)
In the polypropylene resin material used for the sealing material of the present invention, it is preferable that the component (A) and the component (B) are not phase-separated in order to maintain good compatibility and maintain good flexibility. The phase separation conditions are affected not only by the ethylene content but also by the molecular weight and composition. Therefore, in addition to the above-mentioned regulations regarding ethylene and α-olefin content, the temperature obtained by solid viscoelasticity measurement (DMA) − The loss tangent (tan δ) curve preferably has a specific tan δ curve peak.
When component (A) and component (B) have a phase separation structure, the glass transition temperature of the amorphous part contained in component (A) and the glass transition temperature of the amorphous part contained in component (B) are respectively Since it is different, there are a plurality of peaks. Conversely, when they are compatible, both components are mixed in the order of molecules and have a single peak at a temperature intermediate between the glass transition temperatures of both components. That is, whether or not the phase separation structure is taken can be determined in the temperature-tan δ curve in the solid viscoelasticity measurement, and the tan δ curve has a single peak at 0 ° C. or lower in order to improve flexibility. It is preferable.

  Specifically, the measurement of solid viscoelasticity for the determination of the phase separation structure is generated by applying a sinusoidal strain of a specific frequency to a strip-shaped sample piece made of the same composition of the component (A) and the component (B). This is done by detecting the stress that occurs. Here, 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. It shows a sharp peak in the temperature range below 0 ° C. Generally, the peak of the tan δ curve below 0 ° C. is for observing the glass transition of the amorphous part, and here the peak temperature is defined as the glass transition temperature Tg (° C.). Define.

(Melt flow rate (MFR))
The melt flow rate (MFR) of the polypropylene resin material used in the present invention is preferably 0.5 to 100 g / 10 minutes, more preferably 1 to 50 g / 10 minutes, still more preferably 2 to 30 g / 10. Minutes. If the MFR is less than 0.5 g / 10 minutes, molding tends to be difficult, and if it exceeds 100 g / 10 minutes, the flexibility tends to deteriorate.
Here, MFR is a value measured at a heating temperature of 230 ° C. and a load of 21.2 N in accordance with JIS K7210.

(Melting peak temperature (Tm))
Moreover, it is preferable that the melting peak temperature (Tm) measured by the differential scanning calorimeter (DSC) of the polypropylene resin material used by this invention is the range of 110-155 degreeC, and is 120-150 degreeC. Is more preferable. When Tm is less than 110 ° C, heat resistance is liable to be impaired, and the cooling and solidification rate of the melted polypropylene resin material is slow, which may deteriorate moldability. This is not preferable. In addition, in order to adjust Tm, it can adjust easily by controlling the quantity of the alpha olefin supplied to a polymerization reaction system.
The specific measurement of Tm is as described above.

(Molecular weight distribution (Mw / Mn))
The molecular weight distribution (Mw / Mn) measured by the gel permeation (GPC) method of the polypropylene resin material used in the present invention is preferably in the range of 1.5 to 4, more than 1.8, More preferably, it is less than 3. When Mw / Mn is less than 1.5, it is difficult to obtain with the current polymerization technique. When Mw / Mn is more than 4, it is not preferable because the elution property deteriorates and the product (pellet) may become sticky.
The method for adjusting the molecular weight distribution of the propylene-based resin is preferably controlled by polymerization using a catalyst system in which two or more metallocene catalyst components are used in combination, or by performing multistage polymerization of two or more stages during polymerization. Can do. Conversely, in order to adjust the molecular weight distribution narrowly, it can be adjusted by polymerizing a propylene polymer and then melt-kneading it using an organic peroxide.
The measurement of molecular weight distribution is as described above.

(Glass transition temperature Tg)
As described above, the polypropylene resin material used in the present invention has a glass transition temperature Tg, which is a temperature at which the tan δ curve obtained in the temperature-loss tangent curve obtained by solid viscoelasticity measurement has a peak, and is simply 0 ° C. or less. Although it is preferable to have one peak, in order for this Tg to have a single peak, the ethylene content [E] A in component (A) and the ethylene content [E] B in component (B) (Hereinafter also referred to as [E] gap, [E] gap = [E] B- [E] A)) is preferably 20% by weight or less, more preferably 16% by weight or less. [E] gap may be reduced to a range where Tg becomes a single peak in the measurement.
In the sequential polymerization, when the component (B) is polymerized so that the ethylene content [E] B in the component (B) falls within an appropriate range according to the ethylene content [E] A in the component (A). By setting the supply weight ratio of ethylene to propylene, a polypropylene resin material having a predetermined [E] gap can be obtained.

The Tg of the polypropylene resin material that does not take a phase separation structure as used in the present invention is the ethylene content [E] A in the component (A) and the ethylene content [E] B in the component (B), And affected by the ratio of both components. In the present invention, the amount of the component (B) is 30 to 70% by weight, but in this range, Tg is more strongly affected by the ethylene content [E] B in the component (B).
That is, Tg reflects the glass transition of the amorphous part. In the polypropylene resin material used in the present invention, the component (A) has crystallinity and relatively few amorphous parts, whereas the component (A This is because B) is low crystalline or amorphous, most of which is an amorphous part. Therefore, the value of Tg is almost controlled by [E] B, and the control method of [E] B is as described above.

(Other propylene-α-olefin random copolymers, ethylene-α-olefin random copolymers (component (C))
In the polypropylene resin material for the sealing material of the present invention, (C) propylene-α-olefin random copolymer (C-1) or ethylene other than the above components (A) and (B), if necessary. The α-olefin random copolymer (C-2) is preferably 1 to 100 parts by weight, more preferably 2 to 45 parts by weight, based on 100 parts by weight of the total amount of the component (A) and the component (B). More preferably, it can be contained in the range of 3 to 30 parts by weight.

(Propylene-α-olefin random copolymer (C-1))
As the propylene-α-olefin random copolymer (C-1), those having a melting point of 135 ° C. or less as measured by DSC method are preferable. When the melting point is extremely higher than 135 ° C., the flexibility is lowered, and the propylene-α-olefin random copolymer having a melting point of less than 120 ° C. is difficult to produce. preferable.
The propylene-α-olefin random copolymer (C-1) preferably contains propylene units in the range of 85 to 99.9% by weight, more preferably in the range of 90 to 99.9% by weight. desirable.

  As the α-olefin in the propylene-α-olefin random copolymer (C-1), ethylene, butene-1, pentene-1, hexene-1, 4-methyl-pentene-1, and the like can be used. Among these, a random copolymer of propylene and ethylene is preferable. In the random copolymer of propylene and ethylene, the ethylene content is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, and particularly preferably 0.4 to 3.5% by weight. When the ethylene content is less than 0.1% by weight, the impact strength of the product is impaired. On the other hand, when the ethylene content is more than 10% by weight, the elution property of the sealing material tends to be lowered.

  Further, the propylene-α-olefin random copolymer (C-1) can be obtained by using a highly stereoregular polymerization catalyst. As the highly stereoregular polymerization catalyst, titanium chloride, alkoxy titanium, etc. are started. A so-called supported Ziegler-Natta catalyst or a metallocene catalyst using a titanium compound prepared as a material can be used, but those produced with a metallocene catalyst are preferred.

  As the propylene-α-olefin random copolymer (C-1), commercially available products can be used in addition to those obtained by conventional methods. Examples of commercially available products include “NOVATEC PP” (trade name) series manufactured by Nippon Polypro as a product example using a Ziegler catalyst, and “WINTECH” (trade name) manufactured by Nippon Polypro as a product example using a metallocene catalyst. ) Series, Dow Chemical Japan's "Versify" (product name) series, ExxonMobil's "Vistamax" series, Mitsui Chemicals' "Notio" (product name) series, etc., A suitable one can be used.

(Ethylene-α-olefin copolymer (C-2))
The ethylene-α-olefin copolymer (C-2) is a copolymer obtained by copolymerizing ethylene and preferably an α-olefin having 3 to 20 carbon atoms, and the α-olefin is carbon. Preferable examples include those having several 3 to 20, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene and the like.
The ethylene-α-olefin copolymer (C-2) preferably has a narrow crystallinity and molecular weight distribution in order to suppress stickiness and bleed out, and is polymerized by a metallocene catalyst that can narrow the crystallinity and molecular weight distribution. It is desirable to use what was made.

  The ethylene-α-olefin copolymer (C-2) can be appropriately selected from those commercially available as metallocene polyethylene, in addition to those obtained by conventional methods. Examples of commercially available products include DuPont Dow's trade name affinity (AFFINITY) and Engage (ENGAGE), Nippon Polyethylene trade name kernel (KERNEL), ExxonMobil trade name Exact (EXACT), etc. You may choose something.

(Additive)
In the polypropylene resin material of the present invention, it is also desirable to add a nucleating agent, a neutralizing agent, and a lubricant.

(Nucleating agent)
A nucleating agent may be added to the polypropylene resin material of the present invention as long as the effects of the present invention are not significantly impaired. Preferable specific examples of the nucleating agent are commercially available products, such as trade name Hyperform HPN68L (a metal salt of a bicyclic dicarboxylate represented by the following structural formula) manufactured by Meriken Co., Ltd. Examples thereof include known nucleating agents such as nucleating agents, organophosphate nucleating agents, aromatic phosphate esters, and talc.
The blending amount of the nucleating agent is preferably in the range of 0.005 to 0.15 parts by weight and more preferably in the range of 0.01 to 0.1 parts by weight with respect to the propylene-ethylene block copolymer (a). If it is less than 0.005 parts by weight, the effect cannot be obtained, and if it exceeds 0.15 parts by weight, the Japanese Pharmacopoeia test may be rejected.

(Neutralizer)
It is also desirable to add a neutralizing agent to the polypropylene resin material of the present invention. Preferable specific examples of the neutralizing agent include metal fatty acid salts such as calcium stearate, zinc stearate, magnesium stearate, hydrotalcite (trade name: manufactured by Kyowa Chemical Industry Co., Ltd., represented by the following general formula (3). Magnesium aluminum composite hydroxide salt), Mizukarak (trade name: lithium aluminum composite hydroxide salt represented by the following general formula (4), manufactured by Mizusawa Chemical Co., Ltd.), and the like.

Mg _1-x Al _x (OH) ₂ (CO ₃ ) _{x / 2} · mH ₂ O (3)
(In the formula (3), x is 0 <x ≦ 0.5, and m is a number of 3 or less.)
[Al ₂ Li (OH) ₆ ] _n X · mH ₂ O (4)
(In the formula (4), X is an inorganic or organic anion, n is the valence of the anion (X), and m is 3 or less.)

(Lubricant)
It is also desirable to add a lubricant to the polypropylene resin material of the present invention. Examples of the lubricant include known lubricants, but butyl stearate and silicone oil are preferable, and silicone oil is particularly preferable.
Preferred examples of the silicone oil include dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrodienepolysiloxane, α, ωbis (3-hydroxypropyl) polydimethylsiloxane, polyoxyalkylene (C ₂ -C ₄ ) dimethylpolysiloxane. And a polyorgano (C ₁ -C ₂ alkyl group and / or phenyl group) siloxane and polyalkylene (C ₂ -C ₃ ) glycol condensate. Of these, dimethylpolysiloxane and methylphenylpolysiloxane are preferred. The lubricant may be used alone or in combination.
When silicone such as dimethylpolysiloxane is added, not only can scratches that occur during molding be prevented, but also burns that can occur in cylinders and hot runners can be prevented.

  0.001-0.5 weight part is preferable, as for the compounding quantity in the case of using a lubricant, 0.01-0.15 weight part is more preferable, and 0.03-0.1 weight part is especially preferable. If the amount is less than 0.001 part by weight, the effect cannot be expected. If the amount exceeds 0.5 part by weight, not only a further effect cannot be expected, but also economically undesirable.

(Other additives)
In the polypropylene resin material, in addition to each additive component described above, additives such as various antioxidants, ultraviolet absorbers, light stabilizers and the like used as stabilizers for propylene polymers may be blended. it can.

  Specifically, as the antioxidant, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, di-stearyl-pentaerythritol-di-phosphite, bis ( 2,4-di-t-butylphenyl) pentaerythritol-diphosphite, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4 Phosphorous antioxidants such as 4,4'-biphenylene-diphosphonite, tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylene-diphosphonite, 2,6-di-t-butyl-p-cresol, tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane, 1 3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate Phenolic antioxidants such as di-stearyl-ββ'-thio-di-propionate, di-myristyl-ββ'-thio-di-propionate, di-lauryl-ββ'-thio-di-propionate An antioxidant etc. are mentioned preferably.

  Examples of the ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2 Preferred examples include ultraviolet absorbers such as' -hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole.

  Examples of the light stabilizer include n-hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate, 2,4-di-t-butylphenyl-3 ′, 5′-di-t-butyl-4 ′. -Hydroxybenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl-2- (4-hydroxy-2,2,6,6-tetramethyl-1-piperidyl) succinate ) Ethanol condensate, poly {[6-[(1,1,3,3-tetramethylbutyl) amino] -1,3,5-triazine-2,4diyl] [(2,2,6,6- Tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino]}, N, N′-bis (3-aminopropyl) ethylenediamine-2,4- Bis [N-butyl-N- ( , Light stabilizers such as 2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, can be preferably exemplified.

  Further, amine-based antioxidants represented by the following structural formula (5) and the following general formula (6), which have good discoloration resistance and no discoloration by radiation treatment, 5,7-di-t-butyl-3 Preferred examples include lactone antioxidants such as-(3,4-di-methyl-phenyl) -3H-benzofuran-2-one, and vitamin E antioxidants represented by the following structural formula (7). Can do.

（式（６）中、Ｒ_１とＲ_２は炭素数１４〜２２のアルキル基を示す。）

(In Formula (6), R ₁ and R ₂ represent an alkyl group having 14 to 22 carbon atoms.)

  In addition, an antistatic agent, a slip agent, a dispersant such as a fatty acid metal salt, a dye, a pigment, polyethylene, an olefin-based elastomer, and the like can be blended within a range that does not impair the object of the present invention.

(Manufacturing method of sealing material)
The composition for a sealing material of the present invention comprises the above-described component (A), component (B) or a sequential polymerization product comprising both, if necessary, the component (C), an antioxidant, a neutralizing agent. , Lubricant, etc. are put into a Henschel mixer, super mixer, ribbon blender, etc. and mixed, and then in a normal single screw extruder, twin screw extruder, Banbury mixer, plastic bender, roll, etc. in a temperature range of 190-260 ° C It can be obtained by melt-kneading with.

(Seal material)
The sealing material of the present invention can be obtained by molding the above resin composition by various molding methods such as an injection molding method, an extrusion molding method, and a blow molding method, which are known methods.
In addition, the sealing material of the present invention is a container stopper, masking rubber, packing, O-ring, joint sheet, rubber sheet, weather strip, syringe gasket, cap liner material, mouthpiece of food containers such as coffee powder and cream powder. For example, an inner seal material that seals the part may be used.
The food and medical sealing materials may be subjected to known sterilization treatments such as autoclave sterilization, radiation sterilization, EOG sterilization, ultraviolet sterilization, microwave, boiling water, and steam.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is limited to these description and is not interpreted.
In each example and comparative example, the physical properties used were measured by the following method, and the following were used as the propylene polymer, blend material and other additives.
Examples 1 and 2 are reference examples.

1. Measurement method (1) 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%.
(Creation of specimen)
Standard number: JIS-7152 (ISO294-1)
Molding machine: TU-15 injection molding machine manufactured by Toyo Machine Metal Co., Ltd. Molding machine set 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)
Injection pressure: 800 kgf / cm ²
Holding pressure: 800 kgf / cm ²
Holding time: 40 seconds Mold shape: Flat plate (thickness 2 mm, width 30 mm, length 90 mm)

(2) Calculation of the amount of each component Using TREF (temperature rising elution fractionation method), the amount was calculated according to the following conditions and methods.
[apparatus]
(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

(3) Calculation of ethylene content
The ethylene content in the random copolymer was measured by infrared spectroscopy using a characteristic absorber of 733 cm ⁻¹ with an ethylene / propylene random copolymer whose composition was verified by ¹³ C-NMR as a reference substance. The pellets were formed into a film having a thickness of about 500 microns by press molding.

(4) Peak of tan δ curve According to the intrinsic viscoelasticity measurement described above, the composition of component (A) and component (B) was measured.

(5) MFR: Measured according to JIS K7210 at a heating temperature of 230 ° C. and a load of 21.2 N. The ethylene polymer was measured at a temperature of 190 ° C.

(6) 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 cooling rate of 10 ° C./minute, and further 10 ° C./minute The melting peak temperature was measured when melting at a heating rate.

(7) Molecular weight distribution: measured by the method described above.

(8) Haze value: A value was measured in accordance with JIS K7105 using a sheet piece having a thickness of 2 mm.

(9) Fifteenth revision Japanese Pharmacopoeia study: 45. 1. Plastic chemical container test method (plastic water-based injection container) In accordance with the test method in the section of polyethylene or polypropylene aqueous injection container, transparency, heavy metal, lead, cadmium, ignition residue, foaming, PH, potassium permanganate reducing substance, ultraviolet absorption spectrum, evaporation residue It was measured. However, the sample was prepared by weighing pellets with a thickness of 0.5 mm corresponding to a surface area of 1200 cm ² and pressing at 220 ° C. to obtain a sheet piece having a length of about 5 cm and a width of about 0.5 cm. After being cut into pieces, washed with water, and dried at room temperature. Put this in a hard glass container with an internal volume of about 300 ml, add exactly 200 ml of water, seal it with an appropriate stopper, heat it at 121 ° C for 1 hour using a high-pressure steam sterilizer, and leave it to room temperature. Then, this solution was used as a test solution, and separately with water, a blank test solution was prepared in the same manner.

(10) Durometer hardness D: measured according to JIS K7215.
(11) Thermal deformation temperature (HDT): measured at a load of 0.45 MPa in accordance with JIS K7207.
(12) Bleed on the surface: The sheet surface after heat-treating a sheet piece having a thickness of 2 mm at 100 ° C. for about 1 hour was visually confirmed to evaluate the bleeding property.
A: Bleed is not recognized.
○: Bleed is hardly recognized.
Δ: Bleed is observed.
X: Bleed is remarkable.

2. Materials used (1) Polypropylene resin material (propylene-ethylene block copolymer (PP-1))
A propylene-ethylene block copolymer (PP-1) was obtained by the following production example by the sequential polymerization method.

[Production Example PP-1]
Preparation of prepolymerization catalyst (chemical treatment of ion-exchange layered 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 of ion-exchange layered silicate)
The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: Cylindrical inner diameter 50mm Heating zone 550mm (electric furnace)
Rotating speed with lifting blade: 2rpm
Tilt angle: 20/520
Silicate supply 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 the silicate was introduced, 1,160 ml of mixed heptane and 840 ml of a heptane solution of triethylaluminum (0.60 M) were added and 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 ML) was added to the silicate slurry prepared above and reacted at 25 ° C. for 1 hour. In parallel, 270 ml of (r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] 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 ML) and 5600 ml of mixed heptane were further added, stirred at 40 ° C. for 30 minutes, allowed to stand for 10 minutes, and then 5600 ml of the supernatant was removed. This operation was further repeated 3 times. When the component analysis of the final supernatant was conducted, 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 with respect to the amount charged. Was 0.016%. Subsequently, 170 ml of a heptane solution of triisobutylaluminum (0.71 ML) 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.

(First step)
In the first step, propylene-ethylene random copolymerization was carried out using a liquid phase polymerization layer with an agitator having an internal volume of 0.4 m ³ . Liquefied propylene, liquefied ethylene, and triisobutylaluminum were continuously fed at 90 kg / hour, 2.2 kg / hour, and 21.2 g / hour, respectively. The hydrogen supply amount was adjusted so that the MFR in the first step became a target value. Further, the above prepolymerized catalyst was supplied as a catalyst (excluding the weight of the prepolymerized polymer) so as to be 5.4 g / hour. The polymerization tank was cooled so that the polymerization temperature was 65 ° C.
When the propylene-ethylene random copolymer obtained in the first step was analyzed, melting point Tm 138 ° C., Mw / Mn 2.8, BD (bulk density) was 0.46 g / cc, MFR was 2.0 g / 10 min, ethylene The content was 1.5% by weight.

(Second step)
In the second step, propylene-ethylene random copolymerization was performed using a stirred gas phase polymerization tank having an internal volume of 0.5 m 3. The slurry containing polymer particles was continuously withdrawn from the liquid phase polymerization tank in the first step, flushed with liquefied propylene, and then pressurized with nitrogen and continuously supplied to the gas phase polymerization tank. The polymerization tank was controlled so that the temperature was 80 ° C. and the total partial pressure of propylene, ethylene, and hydrogen was 1.5 MPa. At that time, the concentrations of propylene, ethylene, and hydrogen in the total partial pressure of propylene, ethylene, and hydrogen were controlled to be 73.99 vol%, 26.00 vol%, and 150 vol ppm, respectively. Furthermore, ethanol was supplied to the gas phase polymerization tank as an activity inhibitor. The supply amount of ethanol was set to 0.3 mol / mol with respect to aluminum in triisobutylaluminum supplied accompanying the polymer particles supplied to the gas phase polymerization tank.

The propylene-ethylene block copolymer (PP-1) thus obtained was analyzed. The activity was 11.2 kg / g-catalyst, the BD was 0.41 g / cc, the MFR was 4.0 g / 10 min, and ethylene was contained. An amount of 6.2% by weight, a melting point Tm of 138 ° C., and Mw / Mn 2.8 of PP-1 was obtained.
PP-1 has an ethylene content of component (A) of 1.3 wt%, a composition ratio of 50 wt%, an ethylene content of component (B) of 11.0 wt%, a composition ratio of 50 wt%, and a tan δ curve. It had a single peak at −12.3 ° C.
Production conditions and results are shown in Table 1.

(Propylene polymer (component (A))
[WFW4]
Propylene-ethylene random copolymer manufactured by Nippon Polypro Co., Ltd .:
Product name "Wintech WFW4", metallocene catalyst used, ethylene 1.9 wt%,
Propylene 98.1% by weight, MFR 7 g / 10 min Melting point (Tm) 135 ° C., Mw / Mn = 2.7

(Propylene polymer (component (B))
[VM3000]
Propylene-ethylene random copolymer manufactured by ExxonMobil:
Product name “Vistamax 3000”, metallocene catalyst used, ethylene 11 wt%, propylene 89 wt%, MFR 8 g / 10 min, melting point (Tm) 129 ° C., Mw / Mn: 1.8

(Ethylene-α-olefin random copolymer (C-2))
Metallocene ethylene-hexene copolymer:
Product name “Kernel KS571” manufactured by Nippon Polytechnic Co., Ltd.
Density (JIS K7112) 0.907 g / cm ³ , MFR (JIS K7210, 190 ° C., 2.16 kg load) 12 g / 10 min

(Lubricant)
Silicone oil:
Product name “Dowcorning 360 Medical Fluid-1000 (M360-1000)” manufactured by Toray Dow Corning Co., Ltd.
(Antioxidant)
(I) Hindered phenolic antioxidants:
Irganox 1010 (IR1010; Ciba, trade name)
Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxylphenyl) propionate] methane (ii) phosphorus antioxidant:
Irgaphos 168 (IF168; Ciba, trade name)
Tris (2,4-di-tert-butylphenol) phosphite

(Examples 1, 3-5, Comparative Examples 1-2)
Each resin component was prepared in the blending ratio (parts by weight) shown in Table 2, and dried with a super mixer together with 0.05 parts by weight of the hindered phenol antioxidant and 0.05 parts by weight of the phosphorus antioxidant. After blending, the mixture was melt kneaded using a 35 mm diameter twin screw extruder. Extruded pellets from the die at a die outlet temperature of 230 ° C. The obtained pellets were injection molded by an injection molding machine at a resin temperature of 230 ° C., an injection pressure of 600 kg / cm ^2, and a mold temperature of 40 ° C. to prepare test pieces. The physical properties were measured using the obtained test pieces. The results are shown in Table 2.

(Example 2)
The above resin components were prepared in the blending ratios (parts by weight) shown in Table 2, and 0.10 parts by weight of the silicone oil described above, 0.05 parts by weight of hindered phenol-based antioxidant and phosphorus-based antioxidant 0. After dry blending with a super mixer together with 05 parts by weight, the mixture was melt-kneaded using a 35 mm diameter twin screw extruder. Extruded pellets from the die at a die outlet temperature of 230 ° C. The obtained pellets were injection molded by an injection molding machine at a resin temperature of 230 ° C., an injection pressure of 600 kg / cm ^2, and a mold temperature of 40 ° C. to prepare test pieces. The physical properties were measured using the obtained test pieces. The results are shown in Table 2.

From Table 2, Example 1 is a block copolymer having the component (A) and the component (B) of the present invention as constituent components, and Example 2 is a blended product of both components, but compared with Comparative Example 1. It can be seen that the material has heat resistance and the hardness D is a level that can be used as a sealing material. It can be seen that Comparative Example 2 has heat resistance but does not have flexibility as in Examples 1 and 2. In addition, it can be seen that Examples 1 and 2 have good dissolution properties, no bleed, and passed (conform) the 15th revised Japanese Pharmacopoeia test.
Moreover, Examples 3-5 are what blended KS571 which is an ethylene-alpha-olefin random copolymer (C-2), and can increase the addition amount and can reduce hardness D and can show a softness | flexibility. However, in Example 5 of 50% by weight, it can be seen that the heat resistance tends to decrease.

(Example 6)
Using the pellets obtained in Example 2, an injection molding machine was used for injection molding at a resin temperature of 240 ° C. and a mold temperature of 35 ° C. to form a container sealing material having an outer diameter of 2 cm and a height of 1 cm. It was confirmed that the sealing material was flexible and the container was kept airtight.

  The sealing material of the present invention has low elution with excellent flexibility and heat resistance, and can be widely used as a sealing material used as a lid material for various containers.

Claims (6)

And the following components (A) 30 to 70 wt% and the following components (B) 70 to 30 wt% seen contains further components (C) a propylene -α- olefin random copolymer or an ethylene -α- olefin random copolymer Is made of a polypropylene resin material containing 1 to 100 parts by weight with respect to 100 parts by weight of the total amount of the component (A) and the component (B) .
Component (A): a propylene polymer satisfying the following conditions (a1) to (a3).
(A1) Melting peak temperature (Tm) measured by DSC method is 125 to 155 ° C.
(A2) The content of a comonomer selected from ethylene and an α-olefin having 4 or more carbon atoms is 0 to 5% by weight.
(A3) Molecular weight distribution (Mw / Mn) measured by GPC method is 1.5-4
Component (B): a propylene-ethylene random copolymer having an ethylene content of 3 to 25% by weight, obtained using a metallocene catalyst.   The composition of component (A) and component (B) is characterized in that in the temperature-loss tangent curve obtained by solid viscoelasticity measurement (DMA), the tan δ curve has a single peak at 0 ° C. or less. Item 10. A sealing material according to item 1.   The polypropylene resin material has a melt flow rate (MFR: 230 ° C. 2.16 kg) of 0.5 to 100 g / 10 minutes, a melting peak temperature (Tm) of 110 to 155 ° C., and a molecular weight distribution (Mw / Mn) of 1.5. It is -4, The sealing material of Claim 1 or 2 characterized by the above-mentioned.   The ethylene content (% by weight) of the component (B) is 3 to 20% by weight greater than the content (% by weight) of the comonomer of the component (A). Sealing material.   The sealing material according to any one of claims 1 to 4, wherein the polypropylene resin material is obtained by melt blending the component (A) and the component (B).   The sealing material according to claim 1, wherein the polypropylene resin material is obtained by sequentially polymerizing the component (A) and the component (B).