JPH0959444A - Polypropylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene resin compsn. with a high clarity by compounding a polypropylene resin with a crystal-nucleating agent and a polyhydric alcohol. SOLUTION: This compsn. comprises 100 pts.wt. polypropylene resin, 0.01-1.0 pt.wt. crystal-nucleating agent, and 0.01-0.1 pt.wt. polyhydric alcohol. A pref, nucleating agent is a di-(substd. benzylidene)sorbitol represented by the formula (wherein R<1> and R<2> are each a 1-8C alkyl, an alkoxy, or a halogen; and (m) and (n) are each an integer of 1-3) and obtd. by the condensation of sorbitol and a substd. arom. aldehyde. Examples of the alcohol are glycerin, sorbitol, pentaerythritol, their condensates, and their alkylene oxide adducts. When further compound with an antistatic agent mainly comprising a fatty acid monoglyceride, this compsn. is high both in clarity and in antistatic effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition having a remarkably improved transparency, and more specifically, a polypropylene resin composition having a remarkably enhanced value as a packaging container by imparting a high degree of transparency. The present invention relates to a polypropylene resin composition in which the charging property as well as the transparency is improved, and adhesion of dust and the like is prevented.

[0002]

BACKGROUND OF THE INVENTION Polypropylene resin has chemical resistance, water vapor barrier property, heat resistance,
Due to its excellent insulation resistance, daily sundries, automobile parts,
Widely used in various fields such as packaging materials and industrial parts. However, since the polypropylene resin is crystalline, it becomes opaque due to scattered light due to the difference in refractive index between the crystalline part and the amorphous part. Therefore, the commercial value may be impaired in some applications such as packaging materials.

Conventionally, a crystal nucleating agent such as dibenzylidene sorbitol, carboxylic acid or a metal salt thereof has been used as an additive in order to improve the transparency of polypropylene resin. By using a crystal nucleating agent, improvement in transparency, surface gloss, etc. is seen, but for example, in the former case, the physical properties of the resin are less deteriorated, but the level has not reached the level of satisfying sufficient transparency, In the latter case, the physical properties of the resin are deteriorated.

Among such crystal nucleating agents, 1,3,2,4-
Di (methylbenzylidene) sorbitol is known to be able to achieve excellent transparency due to its relatively high nucleating agent effect, and is generally used in many cases. However, 1,3,2,4-di (methylbenzylidene) sorbitol has excellent performance as a crystal nucleating agent, but it is expensive as a drawback.
It has not reached the level of satisfying the demand for high transparency. Further, when used in a large amount, there are problems such as odor during processing, sublimation products, thermal decomposition products, etc. adhering to a molding machine or products to generate white powder.

As a method for improving these drawbacks, as a method for preventing white powder generation when dibenzylidene sorbitol is used in Japanese Patent Publication No. 61-36789, various surfactants are used in combination to improve transparency and molding. Although a method for preventing the generation of white powder during processing has been disclosed, the generation of white powder is suppressed by this method, but the transparency has not been significantly improved. Also, in Japanese Patent Publication No. 6-874,
Although a method of imparting a higher degree of transparency by using a (substituted benzylidene) sorbitol in combination with a higher alcohol has been disclosed, this method also does not significantly improve the transparency. Under such circumstances, there has been a strong demand for establishment of a technique for achieving a higher degree of transparency by adding a very small amount.

[0006]

Means for Solving the Problems As a result of various studies on means for improving the transparency of polypropylene resin, the present inventors have found that by using a crystal nucleating agent and a polyhydric alcohol in combination,
It has been found that a high degree of transparency can be imparted, and by using an antistatic agent containing fatty acid monoglyceride as a main component in combination, a higher degree of transparency can be realized and an antistatic effect can be imparted. Came to do. That is, the present invention provides the polypropylene resin compositions shown in the following (1) to (5).

(1) Crystal nucleating agent 0.01 to 1.0 part by weight and polyhydric alcohol 0.01 to 100 parts by weight with respect to 100 parts by weight of polypropylene resin
A polypropylene resin composition having improved transparency, which is characterized by containing 0.1 part by weight. (2) The polypropylene resin composition according to the above (1), wherein the crystal nucleating agent is di- (substituted benzylidene) sorbitol represented by the general formula (I).

[0008]

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(In the formula, R ¹ and R ₂ are the same or different and represent an alkyl group, an alkoxy group or a halogen atom having 1 to 8 carbon atoms. M and n are the same or different and represent an integer of 1 to 3) (3) The polypropylene resin composition according to (1) or (2) above, wherein the polyhydric alcohol is one or more selected from the group consisting of glycerin, sorbitol, pentaerythritol, and derivatives thereof. (4) The polypropylene resin is a propylene homopolymer or a propylene copolymer in which 70% by weight or more of all the constituent monomer components are propylene, and the melt flow rate is 0.1 to 100.
The polypropylene resin composition according to any one of (1) to (3) above, which is a resin of g / 10 min.

(5) Furthermore, 0.1 to 1.0 parts by weight of an antistatic agent containing fatty acid monoglyceride as a main component is blended with 100 parts by weight of polypropylene resin, and the above (1) to (4) 5. A polypropylene resin composition having improved transparency and chargeability according to any one of 1.

In the present invention, as the crystal nucleating agent, di- (substituted benzylidene) sorbitol represented by the above general formula (I) obtained by the condensation reaction of sorbitol and a substituted aromatic aldehyde is preferably used. Examples of the alkyl group represented by R ¹ and R ² in the general formula (I) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group,
a t-butyl group or the like, a methoxy group as an alkoxy group,
Examples of the ethoxy group, n-propoxy group and the like, and examples of the halogen atom include chlorine atom and bromine atom.

Further, in the present invention, the transparency can be further improved by using other known crystal nucleating agent or organic crystallization accelerator together. As these crystal nucleating agents and organic crystallization accelerators, the following compounds can be exemplified. As the crystal nucleating agent, bis (4-t-butylphenyl) sodium phosphate represented by the formula (II), a phosphoric acid represented by the formula (III), which is a metal salt of aromatic phosphoric acid.
2,2'-methylenebis (4,6-di-t-butylphenyl) sodium and the like can be mentioned.

[0013]

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Examples of the organic crystallization accelerator include aliphatic carboxylic acids, aromatic carboxylic acids and metal salts thereof. The aliphatic carboxylic acid, formic acid, acetic acid, propionic acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, aliphatic monocarboxylic acid such as linolenic acid And aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid and fumaric acid. Examples of the aromatic carboxylic acid include phenylacetic acid, benzoic acid, methylbenzoic acid, p-tertiarybutylbenzoic acid, isopropylbenzoic acid, o-toluic acid, and m.
-Toluic acid, p-toluic acid, p-chlorobenzoic acid,
o-bromobenzoic acid, m-bromobenzoic acid, p-bromobenzoic acid, o-nitrobenzoic acid, m-nitrobenzoic acid,
p-nitrobenzoic acid, terephthalic acid, isophthalic acid, salicylic acid, p-hydroxybenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-methoxybenzoic acid, m-
Aromatic carboxylic acids such as methoxybenzoic acid are mentioned.
Examples of these metal salts include salts of metals of Group I of the periodic table such as potassium, sodium and lithium, zinc,
Examples thereof include salts of Group II metals such as calcium and magnesium, and salts of Group III metals such as aluminum.

The blending amount of the crystal nucleating agent in the composition of the present invention is
0.01 to 1.0 parts by weight, preferably 0.05 to 0.5 parts by weight, more preferably 0.05 to 100 parts by weight of the polypropylene resin.
~ 0.3 parts by weight. If the compounding amount of the crystal nucleating agent is less than 0.01 part by weight, the effect of improving transparency is insufficient, and if it is more than 1.0 part by weight, the crystal nucleating agent is expensive and economically disadvantageous. The property improvement effect is saturated and the further effect does not rise, and there is also a problem of odor during molding, adhesion of sublimates and decomposed products during molding to molding machines and products, and bleeding on the surface of molded products. Is not preferred.

Examples of the polyhydric alcohol used in the present invention include glycerin, sorbitol, pentaerythritol, condensates thereof, and alkylene oxide adducts thereof. Regarding sorbitol, there are sorbitan and sorbide as derivatives thereof, but these singly or in a mixture thereof can be preferably used in the present invention.

As the condensate of glycerin, pentaerythritol or the like, in the case of a glycerin condensate, the degree of condensation is preferably 2-10, more preferably 2-5.
belongs to. In the case of a condensate of pentaerythritol, the degree of condensation is preferably 2 or less. When the degree of condensation is larger than this range, the effect of improving transparency is lost and the compatibility with the resin is deteriorated, which is not preferable. Specifically, examples of the condensate of glycerin include diglycerin and triglycerin, and examples of the condensate of pentaerythritol include dipentaerythritol.

Examples of alkylene oxide adducts such as glycerin, sorbitol and pentaerythritol include ethylene oxide and / or propylene oxide adducts. The addition mole number of these alkylene oxides is preferably 1 to 20 moles, more preferably 1
~ 10 moles. If the number of moles of alkylene oxide added exceeds 20 moles, the effect of improving transparency is lost, and the compatibility with the resin deteriorates, which is not preferable. Generally, addition of alkylene oxide gives a mixture having a distribution in the number of added moles, and these mixtures can also be preferably used in the present invention.
These polyhydric alcohols may be used alone or in combination of two or more.

The amount of the polyhydric alcohol in the composition of the present invention is 0.01 to 0 based on 100 parts by weight of the polypropylene resin.
It is 1 part by weight, preferably 0.01 to 0.07 part by weight. If the amount of polyhydric alcohol is less than 0.01 parts by weight, the transparency improving effect cannot be obtained, and if it is more than 0.1 parts by weight, the transparency improving effect reaches saturation, and the mold or product surface is volatilized due to volatilization during molding. Problems such as pollution of

Examples of the polypropylene resin used in the present invention include propylene homopolymer, propylene and other α-olefins such as ethylene, butene-1,4.
-A random copolymer or a block copolymer with methylpentene-1, hexene-1, etc. can be used. Among these, a propylene homopolymer or a propylene copolymer in which 70% by weight or more of all constituent monomer components is propylene is preferable, and the melt flow rate is 0.1 due to moldability and the like.
Particularly preferred are those of -100 g / 10 min.

In the present invention, as the combination of the crystal nucleating agent and the polyhydric alcohol, the following combinations are exemplified as preferable ones, but the present invention is not limited to these combinations. . 1,3,2,4-di (methylbenzylidene) sorbitol and glycerin 1,3,2,4-di (methylbenzylidene) sorbitol and sorbitol 1,3,2,4-di (methylbenzylidene) sorbitol and pentaerythritol 1 , 3,2,4-Di (methylbenzylidene) sorbitol and glycerin ethylene oxide 5 mol adduct 1,3,2,4-di (methylbenzylidene) sorbitol and sorbitol ethylene oxide 6 mol adduct 1,3,2,4 -Di (methylbenzylidene) sorbitol and pentaerythritol ethylene oxide 8 mol adduct 1,3,2,4-di (methylbenzylidene) sorbitol and diglycerin 1,3,2,4-di (methylbenzylidene) sorbitol and triglycerin Addition of 5 mol of 1,3,2,4-di (methylbenzylidene) sorbitol to glycerin and glycerin ethylene oxide 1,3,2,4-Di (methylbenzylidene) sorbitol with sorbitol and sorbitol ethylene oxide 6 mol adduct 1,3,2,4-di (methylbenzylidene) sorbitol with pentaerythritol and pentaerythritol ethylene oxide 8 mol adduct 1,3,2,4-Di (methylbenzylidene) sorbitol with diglycerin and glycerin ethylene oxide 5 mol adduct 1,3,2,4-di (methylbenzylidene) sorbitol with triglycerin and sorbitol ethylene oxide 6 mol adduct .

Further, the polypropylene resin composition of the present invention can have both high transparency and antistatic effect by adding an antistatic agent containing fatty acid monoglyceride as a main component. The proportion of fatty acid monoglyceride in the antistatic agent used in the present invention is preferably 30% by weight or more. When the proportion of fatty acid monoglyceride is less than 30% by weight, the effect of improving transparency is insufficient when used in combination with a polyhydric alcohol. In the present invention, examples of the fatty acid monoglyceride used as the antistatic agent include fatty acid monoglycerides represented by the following general formula (IV).

[0023]

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(In the formula, R ³ represents an aliphatic hydrocarbon group having 7 to 21 carbon atoms.) Another antistatic agent used in combination with the fatty acid monoglyceride is represented by the following general formula (V). N, N-bis (2-hydroxyethyl) alkylamine, the general formula (V
Examples thereof include N, N-bis (2-hydroxyethyl) alkylamide represented by I).

[0025]

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(In the formula, R ⁴ represents an aliphatic hydrocarbon group having 14 to 22 carbon atoms, and R ⁵ represents an aliphatic hydrocarbon group having 11 to 21 carbon atoms.) Fatty acid represented by the general formula (IV) In the monoglyceride, R ³ is an aliphatic hydrocarbon group having 7 to 21 carbon atoms, but 11 to 10 carbon atoms from the viewpoint of antistatic performance and compatibility with the resin.
21 alkyl groups are preferred, most preferably 15 carbon atoms.
And 17 (wherein the R ³ —CO— group is a stearoyl group and / or a palmitoyl group).

Specifically, the fatty acid used when synthesizing the fatty acid monoglyceride represented by the general formula (IV) is
Examples include lauric acid, palmitic acid, stearic acid, myristic acid, behenic acid and the like. Further, for example, a commonly used industrial stearic acid is a mixture of stearic acid and palmitic acid, but a monoglyceride mixture obtained from such a mixed fatty acid is also preferably used. The fatty acid monoglyceride used in the present invention can be easily obtained by an esterification reaction of a fatty acid and glycerin, etc., but generally it is obtained as a mixture of a monoester, a diester and a triester in the esterification reaction. As the fatty acid monoglyceride used in the present invention, such a mixture may be used, but the purified monoester content is high, that is, the so-called high-purity fatty acid monoglyceride exhibits the antistatic effect, kneading into a resin. It is more preferable in terms of compatibility at the time of incorporation.

On the other hand, N, N represented by the above general formula (V)
In-(2-hydroxyethyl) alkylamine,
R ⁴ is an aliphatic hydrocarbon group having 14 to 22 carbon atoms, but from the viewpoint of developing antistatic performance and compatibility with resin, it has 16 to 22 carbon atoms.
And the like, and specific examples thereof include groups such as tetradecyl, hexadecyl, octadecyl, eicosyl, and docosyl. Among them, the case where the number of carbon atoms is 18 (R ⁴ -group is a stearyl group) is most preferable. these
N, N- (2-hydroxyethyl) alkylamine can be easily obtained by a reaction such as adding 2 moles of ethylene oxide to alkylamine, but generally, it is obtained as a mixture having a distribution in the number of addition moles of ethylene oxide,
Further, the alkyl group can be obtained as a mixture having an alkyl distribution derived from the raw materials, and these mixtures are also suitably used in the present invention.

In the N, N-bis (2-hydroxyethyl) alkylamide represented by the above general formula (VI), R ⁵
Is an aliphatic hydrocarbon group having 11 to 21 carbon atoms, but from the viewpoint of antistatic performance expression and compatibility with resins, those having 11 to 17 carbon atoms are preferable, and most preferably 15 and 17 (R ^This is the case where the ^5- CO- group is a stearoyl group and / or a palmitoyl group). Specifically, the fatty acids used when synthesizing the N, N-bis (2-hydroxyethyl) alkylamide represented by the general formula (VI) are lauric acid, palmitic acid, stearic acid, myristic acid, and behenin. Examples thereof include acids. These N, N-bis (2-hydroxyethyl) alkylamides are easily obtained from a fatty acid or a fatty acid alkyl ester and diethanolamine by amidation or aminolysis, but generally have an alkyl distribution derived from the starting alkyl group. It is obtained as a mixture, and these mixtures are also suitably used in the present invention.

The compounding amount of the antistatic agent in the composition of the present invention is 0.1 to 1 with respect to 100 parts by weight of the polypropylene resin.
It is 0 part by weight, preferably 0.2 to 0.5 part by weight. If the content of the antistatic agent is less than 0.1 part by weight, the antistatic effect cannot be obtained, and if it is more than 1.0 part by weight, stickiness or whitening of the surface of the molded product due to excessive bleeding of the antistatic agent occurs, which is not preferable. . The antistatic agent according to the present invention is effective not only for improving antistatic performance but also for improving transparency.

The composition of the present invention contains, as long as the effects of the invention are not impaired, other known components such as stabilizers for resin processing, clarification accelerating aids, antioxidants, plasticizers, ultraviolet absorbers, Pigments, dispersants, lubricants and the like can also be added.
The polypropylene resin composition of the present invention can be produced by an ordinary kneading method. For example, after mixing a polypropylene resin, a crystal nucleating agent, a polyhydric alcohol, and optionally other additives such as an antistatic agent, an antioxidant, and a pigment, with a mixer such as a mixer or a blender. ,
Pellets of the polypropylene resin composition of the present invention can be obtained by pelletizing with an extruder. The obtained pellets are used as a material for various molded articles, but the molding method is not particularly limited, and can be processed into a desired molded article by an injection molding machine, an extrusion molding machine, a press molding machine or the like. Of course, the crystal nucleating agent and the antistatic agent may be directly subjected to molding together with the polypropylene resin without being extruded. Further, a master pellet in which a crystal nucleating agent or an antistatic agent is kneaded in a high concentration, or a granulated one obtained by dropping a molten mixture of the crystal nucleating agent and the antistatic agent onto a cooled belt or the like is molded. At the time of processing, it may be blended with a resin and used for molding.

[0032]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Incidentally, “parts” means “parts by weight” unless otherwise indicated.

Examples 1 to 5 and Comparative Examples 1 to 3 As a polypropylene resin, 100 parts by weight of a propylene-ethylene random copolymer (PJ-420TX manufactured by Tonen Chemical Co., Ltd.) was used as a crystal nucleating agent shown in Table 1. And alcohol in Table 1
After blending in the number of parts by weight shown in and mixing with a super mixer,
Pelleted with a mm extruder. Using this pellet, an injection molding machine is used to mold a 50 x 100 x 2.5 mm test piece,
The transparency was evaluated by the following method. The results are shown in Table 1. <Evaluation Method of Transparency> According to JIS-K6714, the transparency (haze) was measured using a digital turbidimeter (NDH-20D) manufactured by Nippon Denshoku Industries Co., Ltd.

[0034]

[Table 1]

Note) * 1 Gelol MD: 1,3,2,4-di (p-methylbenzylidene) sorbitol (manufactured by Shin Nippon Rika Co., Ltd.) * 2 Sorbitol EO6: 6 mol adduct of sorbitol ethylene oxide Example 6 To 12 and Comparative Examples 4 to 5 As a polypropylene resin, 100 parts by weight of a propylene-ethylene random copolymer (PJ-420TX manufactured by Tonen Kagaku Co., Ltd.) is used as a crystal nucleating agent, a polyhydric alcohol, and a charge shown in Table 2. The inhibitor was mixed in the amount of parts by weight shown in Table 2, and a test piece was molded in the same manner as in Example 1. The obtained test piece was evaluated for transparency in the same manner as in Example 1, and the antistatic property was evaluated by the following method. Table 2 shows the results. <Evaluation method of antistatic property> In a constant temperature / humidity chamber adjusted to 25 ° C and 50% RH, the surface specific resistance value was measured using a high resistance meter (type 4329A manufactured by Hewlett Packard), and Shishido Using a static Honest meter manufactured by Electrostatic Co., Ltd.
Charge half-life was measured.

[0036]

[Table 2]

Note) * 1 Same as Table 1 * 2 Same as Table 1 * 3 Abbreviations of antistatic agents are as follows: C ₁₈ MG: stearic acid monoglyceride C ₁₈ DEA: stearyldiethanolamine C ₁₈ DEAmd: stearyldiethanolamide

[0038]

EFFECTS OF THE INVENTION Molded articles using the polypropylene resin composition in which the crystal nucleating agent of the present invention and a polyhydric alcohol are used in combination have a remarkably high degree of transparency as compared with those using the crystal nucleating agent alone. Further, by further using an antistatic agent containing fatty acid monoglyceride as a main component, higher transparency and antistatic effect can be imparted.

Claims (5)

[Claims] 1. A crystal nucleating agent 0.01 to 1.0 part by weight and a polyhydric alcohol 0.01 to 100 parts by weight with respect to 100 parts by weight of a polypropylene resin.
A polypropylene resin composition having improved transparency, which is characterized by containing 0.1 part by weight. 2. A crystal nucleating agent represented by the general formula (I) is di-
The polypropylene resin composition according to claim 1, which is (substituted benzylidene) sorbitol. Embedded image (In the formula, R ¹ and R ₂ are the same or different and each represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group or a halogen atom.
m and n are the same or different and each represents an integer of 1 to 3. ) 3. The polypropylene resin composition according to claim 1 or 2, wherein the polyhydric alcohol is one or more selected from the group consisting of glycerin, sorbitol, pentaerythritol and derivatives thereof. 4. The polypropylene resin is a propylene homopolymer or a propylene copolymer in which 70% by weight or more of all constituent monomer components are propylene, and has a melt flow rate.
The polypropylene resin composition according to any one of claims 1 to 3, which is a resin of 0.1 to 100 g / 10 minutes. 5. An antistatic agent containing a fatty acid monoglyceride as a main component is further blended in an amount of 0.1 to 1.0 part by weight with respect to 100 parts by weight of the polypropylene resin. A polypropylene resin composition having improved transparency and chargeability according to item 1.