JPH1129666A - Polypropylene composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene composition, hardly having electron charge property immediately after molding into a molded product and improved in mold release property, rustproof property, etc. SOLUTION: This polypropylene composition comprises (a) 100 pts.wt. polypropylene, (b) 0.01-0.3 pts.wt. lithium aluminum complex salt, preferably [LiAl2 (OH)6 ]2 CO3 .1.6H2 O, (c) 0.01-1.0 pts.wt. alkyldiethanol amide and preferably further (d) 0.01-1.0 pts.wt. fatty acid monoglyceride.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene composition which is less likely to be charged by static electricity immediately after molding of a molded article, and has improved releasability and rust prevention. An object of the present invention is to provide a polypropylene composition suitable for applications such as medical parts.

[0002]

2. Description of the Related Art Polypropylene is used in various fields, especially for disposable syringes for daily parts, food containers and medical parts. Polypropylene has a problem that rust is generated in the mold due to chlorine remaining in the catalyst during molding such as injection molding.Conventionally, metal salts of fatty acids that are chlorine scavengers, synthetic hydrotalcite, lithium aluminum composite salts, etc. are compounded. Have been.

[0003]

According to the method of blending the lithium aluminum composite salt, the generation of rust due to the chlorine remaining in the catalyst can be improved satisfactorily, but the lithium aluminum composite salt has poor lubricity, so that the molding of molded articles is difficult. Immediately after that, there is a problem that charging due to static electricity occurs, the releasability is poor, and the molding cycle deteriorates. In addition, in the method of using a metal salt of a fatty acid in combination,
Since the compound has good lubricity, there is little charge due to static electricity immediately after molding of the molded article, and although there is no problem of lowering the molding cycle, the effect of improving rust at the time of molding has not been satisfactory.

[0004] Therefore, it has been an important issue to improve the chargeability of the molded article immediately after molding and to improve the rust prevention property.

[0005] In view of the above background, an object of the present invention is to provide a polypropylene composition having improved charging properties, mold release properties and rust prevention properties immediately after molding of molded articles.

[0006]

Means for Solving the Problems In view of the above problems, the present inventors have intensively studied. As a result, they have found that the above problems can be solved by blending lithium aluminum composite salt and alkyldiethanolamide with polypropylene, and have come to propose the present invention.

That is, the present invention relates to (a) 100 parts by weight of polypropylene, (b) 0.01 to 0.3 parts by weight of a lithium aluminum complex salt, and (c) 0.01 to 1.0 parts by weight of alkyldiethanolamide. And a polypropylene composition comprising:

The polypropylene applied to the present invention is a propylene homopolymer obtained by Ziegler-type catalytic polymerization, or propylene and another α-olefin, for example, an α-olefin having 1 to 8 carbon atoms such as ethylene and 1-butene. -Copolymers with olefins are used. Here, the amount of the α-olefin is within a range that does not impair the effects of the present invention,
It is preferably at most 50% by weight. Further, the copolymer of propylene and another α-olefin may be any of a random copolymer, a block copolymer, and a graft polymer. Furthermore, other α-olefin polymers, for example, other α-olefin homopolymers such as ethylene and 1-butene, or a blend of a copolymer of these other α-olefins with polypropylene may be used. good. The mixing amount is within a range that does not impair the effects of the present invention, and it is generally preferable that the other α-olefin polymer to be blended is 20 parts by weight or less based on 100 parts by weight of polypropylene. In addition, these polypropylenes may be either a polymerization type or a depolymerization type using an organic peroxide. In addition, when this composition is obtained, the desired melt flow rate can be obtained by blending the additive component and an organic peroxide.

In the present invention, by blending the lithium-aluminum composite salt with polypropylene, the resulting polypropylene composition becomes more excellent in rust prevention.

As the lithium aluminum composite salt, one represented by the following general formula [LiAl ₂ (OH) ₆ ] ₂ X · mH ₂ O is usually used. In the formula, X is CO ₃ or SO ₄ , and m is a number from 0 to 3. Among such _{[LiAl 2 (OH) 6]} 2 CO 3 · 1.6H 2 0 [LiAl 2 (OH) 6] 2 SO 4 · 1.2H 2 0 is preferably used.

The amount of these lithium aluminum composite salts is 0.01 to 100 parts by weight of polypropylene.
To 0.3 parts by weight, preferably 0.03 to 0.2 parts by weight. That is, if the amount is less than 0.01 part by weight, sufficient rust prevention cannot be obtained, and if the amount exceeds 0.3 part by weight, the improvement of the chargeability immediately after molding may be adversely affected. It is not preferable because of its properties.

Further, a lithium aluminum composite salt and a metal salt of a fatty acid can be used in combination as long as the chargeability is improved and the rust prevention is not impaired. Examples of metal salts of fatty acids include calcium stearate, zinc stearate, magnesium stearate, lithium stearate, calcium laurate, calcium behenate, calcium montanate, and magnesium 12-hydroxystearate.

Next, in the present invention, in addition to the above-mentioned lithium aluminum composite salt, by blending alkyldiethanolamide with polypropylene, the obtained polypropylene composition has good chargeability immediately after molding of a molded article, The mold releasability at the time is good, and the molding cycle does not decrease.

Here, the alkyl group of the alkyldiethanolamide preferably has 6 to 24 carbon atoms, particularly preferably 8 to 24 carbon atoms.
~ 22 are preferred. For example, lauroyl diethanolamide, palmitoyl diethanolamide, stearoyl diethanolamide and the like are used, and lauroyl diethanolamide is particularly preferable. The mixing amount of these alkyl diethanolamides is
0.01 to 1 part by weight, preferably 0.1 to 1 part by weight, based on 0 part by weight.
03 to 0.8 parts by weight. That is, the amount is 0.0
If the amount is less than 1 part by weight, sufficient improvement of the chargeability immediately after molding cannot be obtained, and if the amount exceeds 1 part by weight, the appearance may be adversely affected by bleeding or the like, which is not preferable.

In the present invention, further, by blending a fatty acid monoglyceride, lubricity in a molding machine or in an injection mold can be further improved, friction with a metal surface can be reduced, and chargeability can be further improved. The fatty acid of this fatty acid monoglyceride has 6 to 24 carbon atoms, preferably 8 to 22 carbon atoms. For example, lauric acid monoglyceride, myristic acid monoglyceride, palmitic acid monoglyceride, stearic acid monoglyceride, behenic acid monoglyceride and the like are used, and stearic acid monoglyceride is particularly preferable. The amount of these fatty acid monoglycerides is 0.01 to 1 part by weight, preferably 0.03 to 1 part by weight, per 100 parts by weight of polypropylene.
0.8 parts by weight. That is, if the amount is less than 0.01 part by weight, the effect of the combined use with the alkyldiethanolamide is not exhibited, and sufficient improvement of the charging property immediately after molding cannot be obtained. On the other hand, if the amount is more than 1 part by weight, the appearance may be adversely affected by bleeding, which is not preferable.

In the present invention, a crystal nucleating agent is preferably added to the above polypropylene composition. As the crystal nucleating agent, it is preferable to use a dibenzylidene sorbitol-based compound, a metal salt of benzoic acid, a metal salt of an organic phosphate, a rosin-based metal salt, or an inorganic powder such as talc. As described above, a mixture of lithium aluminum composite salt and alkyldiethanolamide, or further, a fatty acid monoglyceride is effective for improving the chargeability, rustproofing property and mold release property immediately after molding of polypropylene. By blending the compound, effects such as charging property immediately after molding are more remarkably exhibited.

The dibenzylidene sorbitol compound is 1,3,2,4-dibenzylidene sorbitol or a derivative thereof. Such a dibenzylidene sorbitol compound is conventionally known as a crystal nucleating agent for improving the transparency of polypropylene, and specifically, has the following general formula (I):

[0018]

Embedded image

A compound having a structure represented by the following formula is used without any particular limitation. As the groups represented by R1 to R10 in the formula, hydrogen and known alkyl groups, halogens, methoxy groups and the like can be used. Here, the alkyl group is a known alkyl group having 1 to 18 carbon atoms, such as a methyl group, an ethyl group,
-Butyl group, stearyl group and the like. Halogen is fluorine, chlorine, bromine, iodine. Specifically, besides dibenzylidene sorbitol, for example, di (P-methylbenzylidene) sorbitol, di (P-ethylbenzylidene) sorbitol, di (dimethylbenzylidene) sorbitol, mono (P-methyl) dibenzylidene sorbitol, mono ( Dimethyl) dibenzylidenesorbitol, 1
• 3-P-chlorobenzylidene 2.4-P-methylbenzylidene sorbitol is preferably used.

Examples of the metal benzoate include Pt
-Aluminum butyl benzoate, sodium benzoate,
Lithium benzoate is preferably used.

The organophosphate metal salt is represented by the following formula (II):

[0022]

Embedded image

A compound having a structure represented by the following formula is used without any particular limitation. In the formula, R1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R2 and R3 each represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. M is a metal such as sodium, calcium, and aluminum, m is 1 to 3 and n is 0 to 2, where m + n indicates the valence of the metal. Specifically, sodium-2,2'-methylenebis (4,6-di-t-butylphenyl) phosphate,
Bis (2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo [d, g] [1,3,2]
Dioxaphosphin-6-oxide) aluminum hydroxide, 2,2-methylenebis (4,6-di-t-butylphenyl) phosphate basic aluminum salt and the like are preferably used.

The rosin-based metal salt is represented by the general formula (III)

[0025]

Embedded image

Wherein R1, R2 and R3 are each a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, M is a metal ion having 1 to 3 valences, and n is
And an integer of 1 to 3. )). Specific examples of the alkyl group include methyl, ethyl, n-propyl, 1-propyl,
Examples thereof include alkyl groups having 1 to 8 carbon atoms such as n-butyl, 1-butyl, tert-butyl, pentyl, and octyl, and these groups have a substituent such as a hydroxyl group, a carboxyl group, an alkoxyl group, and a halogen. May be. Specific examples of the cycloalkyl group include cyclopentyl, cyclohexyl, and cycloheptyl having 5 to 5 carbon atoms.
8 cycloalkyl groups, and these groups may have a substituent such as a hydroxyl group, a carboxyl group, an alkoxy group, and a halogen. As the aryl group,
6 to 10 carbon atoms such as phenyl group, tolyl group and naphthyl group
And these groups may have a substituent such as a hydroxyl group, a carboxyl group, an alkoxy group, and a halogen.

The groups represented by R1, R2 and R3 may be the same or different.
Among the compounds represented by the formula (III), R1, R2
And R3 are preferably the same or different alkyl groups, and R1 is a 1-propyl group;
Compounds in which 2 and R3 are methyl groups are more preferred. Such a compound is particularly excellent in the effect of improving the crystallization rate.

Specific examples of the compound represented by the formula (III) include lithium dehydroabietic acid, sodium dehydroabietic acid, potassium dehydroabietic acid, magnesium dehydroabietic acid, calcium dehydroabietic acid, and zinc dehydroabietic acid. And metal salts of dehydroabietic acid.

The amount of these nucleating agents is 0.05 to 1 part by weight, preferably 0.08 to 0.8 part by weight, per 100 parts by weight of polypropylene. That is, if the amount is less than 0.05 part by weight, sufficient rigidity cannot be obtained, and if the amount exceeds 1 part by weight, the rigidity effect reaches a peak, which is not preferable.

The composition of the present invention may further contain, if necessary, other additives such as an ultraviolet absorber, an antistatic agent, a lubricant, a neutralizing agent, a dispersant, a crystallization accelerator, a flame retardant, and a metal-free metal. Activators, fillers, pigments and the like may be blended.

In the present invention, the above-mentioned components can be blended by any ordinary method which is performed by mixing resins. For example, a method in which a lithium-aluminum composite salt component and an alkyldiethanolamide are added to a powdery or pelletized polypropylene component, mixed with a tumbler or a Henschel mixer, and then melt-kneaded with an extruder to form a pellet or the like is preferable. is there. The order of addition of each component is not particularly limited, and each component may be mixed in a different order from the above method. Furthermore, a masterbatch in which each component is concentrated and blended at a high concentration can be prepared and mixed and used.

After preparing a molded article such as a syringe using the composition of the present invention, it may be subjected to radiation sterilization such as γ-rays or electron beams, sterilization or washing of ethylene oxide, propylene oxide, ozone, steam, etc. Even if various treatments are performed, the effect of the present invention is the same as that of a molded article that is not sterilized or washed.

[0033]

According to the present invention, by blending a lithium aluminum composite salt and an alkyldiethanolamide with polypropylene, it is possible to improve the chargeability, releasability and rust prevention immediately after molding of a molded article. . This property of excellent chargeability and releasability immediately after molding is more effective when the polypropylene composition is used for injection molding, and is advantageous because the molding cycle is shortened. Moreover, the property excellent in rust prevention is advantageous because rust of the mold is suppressed.

The polypropylene composition of the present invention having the above-mentioned properties is usefully used for daily parts, food containers, medical parts and the like.

[0035]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to the following Examples.
Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The polypropylenes, additives and their symbols used in the examples are as follows.

1. Polypropylene A1: ethylene-propylene block copolymer (ethylene content: 4% by weight, melt flow rate: 20 g / 10 min.) A2: homopolymer (melt flow rate: 20 g / 10 min.) A3: ethylene-propylene random copolymer (ethylene (Content: 3% by weight, melt flow rate: 20 g / 10 min.) Chlorine scavenger B1: Lithium aluminum composite salt A type [LiAl ₂ (OH) ₆ ] ₂ CO ₃ .1.6H ₂₀ : MIZUKALAC (manufactured by Mizusawa Chemical Industries) B2: Lithium aluminum composite salt B type [LiAl ₂ (OH) _{6] 2 SO 4 · 1.2H 2} 0 B3: calcium stearate (manufactured by NOF Corporation) 3. 3. Antistatic agent C1: lauroyl diethanolamide: LA2000 (manufactured by Miyoshi Oil & Fat) C2: stearoyl diethanolamide C3: stearic acid monoglyceride: electrostripper TS-5 (manufactured by Kao) C4: lauric acid monoglyceride C5: stearoyl diethanolamine Crystal nucleating agent component D1: dibenzylidene sorbitol: denone YK1 (manufactured by Marubishi Yuka) D2: di (P-methylbenzylidene) sorbitol: gelol MD (manufactured by Shin Nippon Rika) D3: hydroxy-Pt-butyl aluminum benzoate : AL-PTBBA (manufactured by Shell Chemical) D4: Sodium-2,2'-methylenebis (4,6-di-t-butylphenyl) phosphate: Adekastab NA-11 (manufactured by Asahi Denka Kogyo) D5: bis (2, 4,8,10-Tetra-t-butyl-6-hydroxy-12H-dibenzo [d, g] [1,3,2] dioxaphosphin-6-oxide) aqueous aluminum oxide D6: potassium dehydroabietic acid (Metal salt component: 30%, dehydroabietic acid: 70%) D7: Talc: High filler # 17 (Matsumura Sangyo) 5. Other components E1: Oleic acid amide (manufactured by NOF Corporation) Examples 1-26, Comparative Examples 1-8 Preparation of a polypropylene composition, preparation of a test sample, and a test method of the effect using the test sample are as follows. I went like that. Tables 1, 2 and 3 show the measurement results of the charging property, mold release property and rust prevention property immediately after molding.

(1) Premixing Tris (2, 4) was added to 100 parts by weight of polypropylene.
-Di-t-butylphenyl) phosphite: 0.08 part by weight, tetrakis [methylene- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane: 0.05 part by weight, Table 1, Various components shown in Tables 2 and 3 were blended and premixed with a Henschel mixer.

(2) Pelletization The above mixture was pelletized at a resin temperature of 230 ° C. using a 50 mmφ extruder (full flight type screw, cylinder: L / D = 28, with vent).

(3) Effect test (a) Charging properties A test specimen (thickness: 2 mmt) was injection-molded (cylinder temperature: 230 ° C., mold temperature: 40 ° C.), and the test was carried out immediately after molding and before mold release. The charged potential at a position 20 mm from the surface of the test sample piece was measured.

(B) Release Property The test molded article shown in FIG. 1 was injection molded (cylinder temperature:
(230 ° C., mold temperature: 40 ° C.), the maximum stress at the time when the ejection pin pushed out the molded product at the time of mold release was measured.

(C) Rust prevention The mild steel sheet whose surface was polished was put into a pellet, placed in an oven at 230 ° C. for 20 hours, the steel sheet was taken out, and the resin attached to the steel sheet was wiped off. It was hung in a glass container containing a small amount of water and left at room temperature for 7 days. The rusting property of the surface of the mild steel sheet after standing was evaluated on the following five levels. If the rusting degree is 2 or less, there is no practical problem.

5: Rust occurred on the entire surface 4: Rust occurred abnormally in 30% of the area 3: Rust occurred in less than 30% of the area 2: Rust occurred to the extent of cloudiness 1: Rust occurred Did not

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[Brief description of the drawings]

FIG. 1 is a perspective view of a test molded product prepared for a releasability test in Examples and Comparative Examples.

Claims (3)

[Claims] 1. A polypropylene composition comprising: (a) 100 parts by weight of polypropylene; (b) 0.01 to 0.3 parts by weight of a lithium aluminum complex salt; and (c) 0.01 to 1.0 part by weight of an alkyldiethanolamide. Stuff 2. The polypropylene composition according to claim 1, further comprising (d) 0.01 to 1.0 part by weight of a fatty acid monoglyceride. 3. The polypropylene composition according to claim 1, further comprising (e) a crystal nucleating agent in an amount of 0.05 to 1.0 part by weight.