JP6986367B2 - Polyolefin resin composition and molded product - Google Patents

Description

The present invention relates to a polyolefin resin composition containing polyolefin as a main component and a molded product.

Since the polyolefin resin composition is inexpensive and has good mechanical properties and moldability, for example, packaging materials, industrial materials, agricultural materials, construction materials, daily necessities, automobile parts, electrical equipment parts, and electronic devices. It is used in a wide range of fields such as equipment parts.
Generally, the polyolefin resin composition contains an antioxidant for the purpose of preventing oxidative deterioration of the polyolefin resin as the main component. At that time, as the antioxidant compounded in the resin, a phenol-based antioxidant and a phosphorus-based antioxidant are often used in combination (Patent Documents 1 to 3). The reason for this is the expectation for a synergistic effect due to the combined use. That is, while phenol-based antioxidants have the function of capturing alkyl peroxy radicals generated by oxidative deterioration of resins due to light and heat and reducing them to alkyl peroxides, phosphorus-based antioxidants have alkyl peroxides. This is because it has a function of stopping the oxidative deterioration reaction by further reducing the oxide as a chemical substance to a highly stable alcohol. Furthermore, although phosphorus-based antioxidants are susceptible to autoxidation when used alone, phenol-based antioxidants suppress this, while phosphorus-based antioxidants suppress yellowing and coloring of phenol-based antioxidants to some extent. This is because it has the effect of Further, in the polyolefin resin composition, a higher fatty acid ester such as stearic acid monoglyceride may be blended for the purpose of enhancing the anti-fog property or the antistatic property of the molded product (Patent Document 4).

Japanese Unexamined Patent Publication No. 2015-209497 Japanese Unexamined Patent Publication No. 2001-114908 Japanese Unexamined Patent Publication No. 7-118568 Japanese Unexamined Patent Publication No. 2015-961

However, when a higher fatty acid ester is blended in a conventional polyolefin resin composition, molding defects called black spots and discoloration may occur during molding. According to the method of Patent Document 1, a method of preparing a resin composition containing a phenol phosphorus-based antioxidant, a phenol-based antioxidant and a phosphorus-based antioxidant has been proposed, but higher fatty acids are used in hot and humid summer. Black spots and discoloration were also observed in the experimental process of molding the resin composition containing the ester. If the amount of the phenol phosphorus-based antioxidant was simply reduced or not used in order to suppress the occurrence of black spots and discoloration, the antioxidant property became insufficient. If the amount of the phenol-based antioxidant is increased for the purpose of supplementing the phenol component contained in the phenol-phosphorus-based antioxidant in order to ensure sufficient antioxidant properties, the quantification will proceed due to the reaction with the nitrogen oxide gas contained in the atmosphere. As a result, it is presumed that a stillbenquinone type, which is a yellowing coloring substance, is produced, and pellets and molded products made of polyolefin resin compositions are yellowing colored over time during transportation and storage, resulting in quality stability and designability. Another problem occurred, such as damage to.
INDUSTRIAL APPLICABILITY The present invention provides a polyolefin resin composition and a molded product which are excellent in antioxidant and anti-yellowing properties and which can sufficiently prevent the occurrence of black spots and burns during molding even though they contain a higher fatty acid ester. With the goal.

The polyolefin resin composition according to one aspect of the present invention comprises a polyolefin, a higher fatty acid ester which is an esterified product of a saturated fatty acid having 10 to 30 carbon atoms, and a phosphorus-based oxidation represented by the following chemical formula (I) or the following chemical formula (II). It contains an inhibitor and a one-sided hindered phenol-based antioxidant, and the content of the higher fatty acid ester is 0.1 to 1.0 part by mass with respect to 100 parts by mass of the polyolefin, and the one-sided hindered phenol-based antioxidant. The content of the agent is 0.03 to 0.3 parts by mass with respect to 100 parts by mass of the fatty acid, and the content of the phosphorus-based antioxidant is 0.03 to 0.3 parts by mass with respect to 100 parts by mass of the fatty acid. ..

In the formula (I), a is an integer of 1 to 3.
^{R 1} and R ² in the formula (II) are independently hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, and the number of carbon atoms. An alkylcycloalkyl group according to any one of 6 to 12, an aralkyl group according to any one having 7 to 12 carbon atoms, or a phenyl group.
R ³ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkylcycloalkyl group, an aralkyl group or a phenyl group. When R ³ is an aralkyl group or a phenyl group, at least one hydrogen atom of the aromatic ring may be substituted with a hydroxy group.
X represents a sulfur atom or a -CHR ⁴ - is a radical ^{(R 4} is a hydrogen atom, or an alkyl group having 1 to 8 carbon atoms, or any cycloalkyl group having a carbon number of 5-8.).

In the polyolefin resin composition of this embodiment, it is preferable that the polyolefin is polypropylene.
The polyolefin resin composition of this embodiment preferably has a haze of 50% or less as measured based on JIS K7136 when a small square plate having a thickness of 1.0 mm specified in JIS K7152-3 is molded.
The molded product of this embodiment contains the above-mentioned polyolefin resin composition.

The polyolefin resin composition and molded product of the present invention are excellent in antioxidant and anti-yellowing properties, and even though they contain a higher fatty acid ester, they can sufficiently prevent the occurrence of black spots and burns during molding.

<Polyolefin resin composition>
The polyolefin resin composition of one aspect of the present invention contains a polyolefin, a higher fatty acid ester, a single hindered phenolic antioxidant, and a specific phosphorus-based antioxidant described below.

(Polyolefin)
Examples of the polyolefin used in this embodiment include polypropylene, polyethylene, ethylene / propylene copolymer, ethylene / propylene / conjugated diene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, and ethylene. Examples thereof include 1-octene copolymers, propylene / 1-butene copolymers, propylene / 1-hexene copolymers, propylene / 1-octene copolymers and the like.
The polypropylene may be homopolypropylene, block polypropylene, or random polypropylene.
The polyethylene may be any of ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, and high density polyethylene.
One type of polyolefin may be used alone, or two or more types may be used in combination.
Among the above-mentioned polyolefins, polypropylene is preferable in that the effect of the present invention is particularly exhibited.

(Higher fatty acid ester)
The higher fatty acid ester used in this embodiment is an esterified product of saturated fatty acid having 10 to 30 carbon atoms. As the higher fatty acid ester, an ester compound or a partial ester compound of a saturated fatty acid having 10 to 30 carbon atoms and a monovalent or polyvalent alcohol having 1 to 20 carbon atoms can be used because it can exhibit more antifogging property and antistatic property. preferable.
Specific examples of the higher fatty acid ester include stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid monosorbite, stearyl stearate, palmitate monoglyceride, palmitate diglyceride, palmitate triglyceride, and palmitate monosorbitate. , Stearic acid stearyl, behenic acid monoglyceride, behenyl behenate, pentaerythritol monostearate, pentaerythritol tetrastearate, pentaerythritol tetrapelargonate, propylene glycol monostearate, palmityl palmitate, butylstearate, methyllaurate, Examples thereof include isopropyl palmitate, biphenyl biphenylate, sorbitan monostearate, 2-ethylhexyl stearate and the like. One type of higher fatty acid ester may be used alone, or two or more types may be used in combination.
Among the higher fatty acid esters, stearic acid monoglyceride or palmitic acid monoglyceride is preferable because it sufficiently exhibits anti-fog and antistatic properties and is inexpensive and easily available.

The content of the higher fatty acid ester is 0.1 to 1.0 part by mass, preferably 0.15 to 0.6 part by mass with respect to 100 parts by mass of the polyolefin. If the content of the higher fatty acid ester is less than the lower limit, anti-fog or antistatic properties may not be exhibited, and if it exceeds the upper limit, the higher fatty acid ester exudes to the surface, resulting in the appearance of the molded product. Defects may occur.

(One-sided hindered phenolic antioxidant)
The one-sided hindered phenolic antioxidant used in this embodiment has a bulky substituent as a sterically damaging substituent such as a t-butyl group only at one ortho position based on the hydroxy group of the phenol. The other ortho-position has a non-sterically damaging substituent such as a first alkyl group such as a hydrogen atom, a methyl group or an ethyl group, and does not contain a phosphorus atom. In addition to the t-butyl group, the bulky substituent is a branched alkyl group having 5 or more carbon atoms, in which one or two of the terminal alkyl groups are methyl groups and the other is a linear or branched alkyl group having 2 to 10 carbon atoms. Alkyl group, linear or branched alkyl group having 2 to 10 carbon atoms, cycloalkyl group having 5 to 10 carbon atoms, alkylcycloalkyl group having 6 to 12 carbon atoms The basis etc. can be mentioned. Bulky substituents do not contain methyl groups.
The t-butyl group is preferable as the bulky substituent from the viewpoint of easy dispersion in the polyolefin resin composition, the antioxidant performance of the obtained phenolic antioxidant, and the balance with the production cost. Since the phenolic antioxidant has a bulky substituent, the formation of the stylbenquinone type, which is a yellowing coloring substance, can be suppressed to some extent, but the one-sided phenolic antioxidant has a chemical structural asymmetry. It is presumed that increasing the amount further enhances the suppression and prevents yellowing and coloring of the polyolefin resin composition at a high level.
In the present specification, the above-mentioned one-sided hindered phenol-based antioxidant may be referred to as "one-sided hindered phenol-based antioxidant (B)".

Specific examples of the one-sided phenolic antioxidant (B) include, for example, (3,9-bis [1,1-dimethyl-2- [β- (3-t-butyl-4-hydroxy-5-). Methylphenyl) propionyloxy] ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,3,5-tris- (4-t-butyl-3-hydroxy-2,6-- Dimethylbenzyl) isocyanurate, 4,4'-thiobis (3-methyl-6-t-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, tri Examples thereof include ethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate]. One hindered phenolic antioxidant (B) is used alone. You may use two or more kinds together.
Among the single hindered phenolic antioxidants (B), (3,9-bis [1,1-dimethyl-2- [1,1-dimethyl-2- [1,1-dimethyl-2- [1,1-dimethyl-2-[ β- (3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane or 1,3,5-tris- (4-t-Butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate is preferred.

The content of the one-sided hindered phenolic antioxidant (B) is 0.03 to 0.3 parts by mass, preferably 0.03 to 0.15 parts by mass with respect to 100 parts by mass of the polyolefin. If the content of the one-sided hindered phenolic antioxidant (B) is less than the lower limit value, the antioxidant performance may be insufficient, and if it exceeds the upper limit value, economic efficiency is impaired.

(Phosphorus-based antioxidant)
The phosphorus-based antioxidant used in this embodiment is a compound represented by the above chemical formula (I) or the above chemical formula (II). In the present specification, the phosphorus-based antioxidant represented by the above chemical formula (I) and the phosphorus-based antioxidant represented by the above chemical formula (II) are referred to as "phosphorus-based antioxidant (C)". There is.

The phosphorus-based antioxidant represented by the chemical formula (I) is a phosphite ester having three hindered aryl groups in the molecule.
Specific examples of the phosphorus-based antioxidant represented by the chemical formula (I) include tris (2,4-di-t-butylphenyl) phosphite, tris (2-t-butylphenyl) phosphite, and tris (2-t-butylphenyl) phosphite. Examples thereof include 4-t-butylphenyl) phosphite and tris (2,4,6-tri-t-butylphenyl) phosphite. The phosphorus-based antioxidant represented by the chemical formula (I) may be used alone or in combination of two or more.
Among the phosphorus-based antioxidants represented by the chemical formula (I), tris (2,4-di-t-butylphenyl) phosphite is available because it exhibits sufficient antioxidant properties and is easily available. preferable.

The phosphorus-based antioxidant represented by the chemical formula (II) has two hindered aryl groups in the molecule, and the two hindered aryl groups have a sulfur atom or a methylene group (methylene group has a substituent). It is a phosphite ester that is cross-linked via (may be).
^{R 1} and R ² in the formula (II) are independently hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, and the number of carbon atoms. An alkylcycloalkyl group according to any one of 6 to 12, an aralkyl group according to any one having 7 to 12 carbon atoms, or a phenyl group.
Examples of the alkyl group in R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group and t. -Pentyl group, i-octyl group, t-octyl group, 2-ethylhexyl group and the like can be mentioned.
Examples of the cycloalkyl group in R ¹ and R ² include a 1-methylcyclopentyl group, a 1-methylcyclohexyl group, a 1-methyl-4-i-propylcyclohexyl group and the like.
Examples of the aralkyl group in R ¹ and R ² include a benzyl group, an α-methylbenzyl group, an α, α-dimethylbenzyl group and the like.
The R ^1, t-butyl group, t-pentyl group, t-alkyl group such as t-octyl group, a cyclohexyl group, 1-methylcyclohexyl group are preferred.
The R ^2, a hydrogen atom or a methyl group is preferable.
^{R 3} in the formula (II) is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkylcycloalkyl group, an aralkyl group or a phenyl group. In the case of an aralkyl group or a phenyl group, the case of having a hydroxy group on an aromatic substituent is also included.
Examples of the alkyl group in R ³ include a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group and the like, in addition to the same alkyl groups as ^{R 1} and R ^2.
Examples ^{of the cycloalkyl group and the aralkyl group in R 3} include the same cycloalkyl group and aralkyl group as in R ¹ and R ² .
X in the formula (II) is a sulfur atom or a −CHR ⁴ − group (R ⁴ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. .).
Examples ^{of the alkyl group and cycloalkyl group in R 4} include the same alkyl group and cycloalkyl group as in R ¹ and R ² .
The phosphorus-based antioxidant (C) represented by the chemical formula (II) may be used alone or in combination of two or more.
Among the phosphorus-based antioxidants (C) represented by the chemical formula (II), 2,2-methylenebis (4,6-di-t) has sufficient antioxidant properties and is easily available. -Butylphenyl) 2-ethylhexylphosphite is preferred.

The content of the phosphorus-based antioxidant (C) is 0.03 to 0.3 parts by mass, preferably 0.03 to 0.15 parts by mass with respect to 100 parts by mass of the polyolefin. If the content of the phosphorus-based antioxidant (C) is less than the lower limit value, the antioxidant performance may be insufficient, and if it exceeds the upper limit value, economic efficiency is impaired.

(Other antioxidants)
In the polyolefin resin composition of this embodiment, a phenol-based antioxidant other than the one-sided hindered phenol-based antioxidant (B) and a phosphorus-based antioxidant (C) other than the above-mentioned phosphorus-based antioxidant (C) are used as long as the effects of the present invention are not impaired. May contain a phosphorus-based antioxidant.
Examples of the phosphorus-based antioxidant other than the phosphorus-based antioxidant (C) include distearyl pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, and bis (2,). 4-di-t-butyl-6-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-dikumil) Phenyl) pentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-diphenylenediphosnite, bis (2,4-di-t-butyl-6-methylphenyl) Ethylphosphite, 2- (2,4,6-tri-t-butylphenyl) -5-ethyl-5-butyl-1,3,2-oxaphosphorinan, 2,2', 2''-nitrilo [ Triethyl-tris (3,3', 5,5'-tetra-t-butyl-1,1'-biphenyl-2,2'-diyl) phosphite, triphenylphosphite, triisodecylphosphite, trisnonyl Phenylphosphite, 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4-hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1, 3,2] Dioxaphosfepine and the like can be mentioned.
As the phenol-based antioxidant other than the one-sided hindered phenol-based antioxidant (B), both hindered phenol-based antioxidants having bulky substituents at both ortho positions based on the hydroxy group of phenol are used. Can be mentioned.
Specific examples of the phenolic antioxidant other than the one-hindered phenolic antioxidant (B) include 2,6-di-t-butyl-4'-methylphenol and tetrakis [methylene-3 (3', 5'). -Di-t-butyl-4-hydroxyphenyl) propionate] methane, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4 6-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 1,3,5-Tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, pentaerythritol- Tetrakiss [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate ], 2,2-thiobis-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2'-methylene-bis- (4-6-di-t-) Butylphenol), 2,2'-ethylidene-bis- (4-6-di-t-butylphenol) and the like.
However, in order to fully exert the effect of the present invention, the polyolefin resin composition of the present embodiment contains a phenolic antioxidant other than the one-sided hindered phenolic antioxidant (B) and the phosphorus-based oxidation. It is preferable not to contain a phosphorus-based antioxidant other than the inhibitor (C).

(Filler)
The polyolefin resin composition of this embodiment may contain a filler as long as the effect of the present invention is not impaired. The filler is added mainly for the purpose of improving the rigidity of the material.
Examples of the filler include inorganic fillers such as talc, clay, calcium carbonate, magnesium hydroxide and glass fiber, and organic fillers such as carbon fiber and cellulose fiber. In order to improve the dispersibility of these fillers, if necessary, surface treatment of the filler or preparation of a masterbatch of the filler and the resin may be performed. Among the fillers, talc is preferable because it easily mixes with polyolefin and easily improves the rigidity of the molded product. The content of the filler may be a known amount.

(Other ingredients)
Further, in the polyolefin resin composition of this embodiment, as optional components, for example, a chlorine absorber, a heat-resistant stabilizer, a light stabilizer, an ultraviolet absorber, an internal lubricant, an external lubricant, an antiblocking agent, a crystal nucleating agent, and a difficulty Includes other additives such as flame retardants, dispersants, copper damage inhibitors, neutralizers, plasticizers, foaming agents, anti-bubble agents, cross-linking agents, peroxides, oil spreads and pigments (organic or inorganic). May be good. The addition amount of each additive may be a known amount.
Further, a resin or rubber other than the polyolefin resin may be contained as long as the effect of the present invention is not impaired. The polyolefin resin composition may contain only one type of resin or rubber, or may contain two or more types. The content may be a known amount.

<Molded product>
The molded product of this embodiment is a molded product obtained by molding the above-mentioned polyolefin resin composition.
The molding method of the polyolefin resin composition is appropriately selected according to the shape of the target molded product, and for example, an injection molding method, an extrusion molding method, a compression molding method, a hollow molding method and the like can be applied. Further, after forming into a sheet using an extrusion molding machine, this sheet may be formed into a desired shape by a secondary processing method such as a vacuum forming method or a pressure forming method.

In general, higher fatty acid esters are easy to absorb moisture and may be hydrolyzed. Hydrolysis of higher fatty acid esters produces higher fatty acids that are acidic. Conventional phosphorus-based antioxidants are easily hydrolyzed under acidic conditions, and it is presumed that the phosphoric acid generated by the hydrolysis causes black spots and discoloration during molding. In particular, in a hot and humid environment such as summer, the amount of moisture absorbed in the resin composition is large, so that it is presumed that the phosphorus-based antioxidant is more likely to be hydrolyzed, and black spots and burns are more likely to occur during molding.
In this embodiment, in a polyolefin resin composition containing a higher fatty acid ester, both a single hindered phenolic antioxidant (B) and a phosphorus-based antioxidant (C) are blended as antioxidants. With this combination of antioxidants, it is possible to sufficiently prevent the occurrence of black spots and burns during molding even in the presence of higher fatty acid esters. The reason is not clear, but it is presumed that the phosphorus-based antioxidant (C) has a hydrophobic group having high steric hindrance around the phosphorus atom, which makes it difficult for water molecules to approach and hydrolysis. .. Further, it is considered that the one-sided hindered phenolic antioxidant (B) is less likely to undergo a dimerization reaction due to its asymmetry in chemical structure, and is less likely to form a stilbene quinone type, which is a yellowing coloring substance. Furthermore, the autoxidation of the phosphorus-based antioxidant (C) can be sufficiently suppressed. On the other hand, since the phosphorus-based antioxidant (C) prevents the oxidation of the one-sided hindered phenol-based antioxidant (B), the polyolefin resin composition of this embodiment and its molded product have anti-yellowing and antioxidant properties. Presumed to be excellent.
The higher the transparency of the molded product, the easier it is to see the occurrence of black spots and burns. Therefore, the present invention exerts a higher effect on the transparent polyolefin resin composition. Such a polyolefin resin composition has a haze of preferably 50% or less, more preferably 50% or less, as measured based on JIS K7136 when a small square plate having a thickness of 1.0 mm specified by JIS K7152-3 is molded. It is 45% or less, more preferably 40% or less, and particularly preferably 35% or less.

Examples and comparative examples are shown below, but the present invention is not limited to the following examples.
(Measurement condition)
1) Melt flow rate (MFR)
The melt flow rate (MFR) of the resin was measured in accordance with JIS K7210-1 under the conditions of a temperature of 230 ° C. and a load of 2.16 kg.
2) Unit amount derived from ethylene For a sample dissolved in a mixed solvent of 1,2,4-trichlorobenzene / deuterated benzene ^{, using JNM LA-400 (13} C resonance frequency 100 MHz) ^{manufactured by JEOL Ltd., 13} C- It was measured by the NMR method.
3) Extreme viscosity of xylene-soluble component (XSIV)
The xylene-soluble component of the polypropylene-based resin was obtained by the following method, and the ultimate viscosity (XSIV) of the xylene-soluble component was measured.
2.5 g of a polypropylene sample was placed in a flask containing 250 mL of o-xylene (solvent), and the resin composition was stirred for 30 minutes at 135 ° C. using a hot plate and a reflux device while purging with nitrogen. After complete dissolution, it was cooled at 25 ° C. for 1 hour. The resulting solution was filtered using filter paper. 100 mL of the filtrate after filtration was collected, transferred to an aluminum cup or the like, evaporated to dryness at 140 ° C. while purging with nitrogen, and allowed to stand at room temperature for 30 minutes to obtain a xylene-soluble component.
The ultimate viscosity was measured in tetrahydronaphthalene at 135 ° C. using an automatic capillary viscosity measuring device (SS-780-H1, manufactured by Shibayama Kagaku Kikai Seisakusho Co., Ltd.).

(Each Example and Each Comparative Example)
Polypropylene, higher fatty acid ester, phenolic antioxidant, and phosphorus-based antioxidant are mixed according to the formulations shown in Tables 1 and 2, and calcium stearate is added as a neutralizing agent in an amount of 0.05% by mass to obtain a mixture. rice field. Next, the mixture was melt-kneaded using an extruder (manufactured by Technobel Co., Ltd., screw diameter 15 mm, isodirectional twin-screw extruder) in which the screw temperature was set to 230 ° C. The molten mixture was then ejected from the extruder and cooled to form strands, which were then cut to give pellets of the resin composition.
Each component used in each Example and each Comparative Example is shown below.

PP1: Blocked polypropylene, MFR: 50 g / 10 min A solid catalyst in which Ti and diisobutylphthalate as an internal donor were supported on _{MgCl 2 was prepared by the method described in Example 5 of European Patent No. 728769.} .. Next, using the solid catalyst, triethylaluminum (TEAL) as the organoaluminum compound, and dicyclopentyldimethoxysilane (DCPMS) as the external electron donor compound, the mass ratio of TEAL to the solid catalyst was 20, and the mass ratio of TEAL / DCPMS was 20. The contact was carried out at 12 ° C. for 24 minutes in an amount such that Prepolymerization was carried out by holding the obtained catalyst system in a suspended state in liquid propylene at 20 ° C. for 5 minutes.
The obtained prepolymer is introduced into the first-stage polymerization reactor of a polymerization apparatus equipped with a two-stage polymerization reactor in series to produce a propylene homopolymer, and ethylene-butene is produced in the second-stage polymerization reactor. -1 Polymerization was produced. During the polymerization, the temperature and pressure were adjusted, and hydrogen was used as a molecular weight adjusting agent.
The ratio of the polymerization temperature to the reactants was that the polymerization temperature and hydrogen concentration were 70 ° C. and 0.97 mol% in the first stage reactor, respectively, and the polymerization temperature, H2 / C2 and C4 / in the second stage reactor. (C2 + C4) had 80 ° C., 0.27 mol%, and 0.41 mol ratios, respectively. Further, the residence time distributions of the first stage and the second stage were adjusted so that the amount of the copolymer component was 27.0% by mass.
The obtained polypropylene polymer (PP1: block polypropylene) has MFR = 50 g / 10 minutes, propylene homopolymer: propylene-ethylene copolymer = 73:27 (mass ratio), ethylene-derived unit of ethylene-butene-1 copolymer = It was 81% by mass and XSIV = 1.1 dL / g.

-PP2: Random polypropylene, MFR: 45 g / 10 minutes A solid catalyst used for polymerization was prepared by the method described in Example 1 of European Patent No. 674991. The solid catalyst is made by supporting Ti and diisobutyl phthalate as an internal donor on _{MgCl 2 by the method described in the above patent publication.} The amount of the solid catalyst and triethylaluminum (TEAL) and dicyclopentyldimethoxysilane (DCPMS) so that the mass ratio of TEAL to the solid catalyst is 11 and the mass ratio of TEAL / DCPMS is 10, 5 at -5 ° C. Contacted for minutes. Prepolymerization was carried out by holding the obtained catalyst system in a suspended state in liquid propylene at 20 ° C. for 5 minutes.
After introducing the obtained prepolymer into a polymerization reactor, hydrogen, propylene and ethylene were fed to set the polymerization temperature, hydrogen concentration and ethylene concentration at 75 ° C., 1.30 mol% and 0.66 mol%, respectively. A propylene-ethylene copolymer was produced by adjusting the pressure.
The obtained polypropylene polymer (PP2: random polypropylene) contained 2.5% by mass of ethylene-derived units and had an MFR of 45 g / 10 min.

-PP3: Random polypropylene, MFR: 2.5 g / 10 minutes The solid catalyst used for the polymerization of PP2, triethylaluminum (TEAL) and cyclohexylmethyldimethoxysilane (CHMMS), the mass ratio of TEAL to the solid catalyst is 8, TEAL. Contact was carried out at −5 ° C. for 5 minutes in an amount such that the mass ratio of / CHMMS was 6.5. Prepolymerization was carried out by holding the obtained catalyst system in a suspended state in liquid propylene at 20 ° C. for 5 minutes.
After introducing the obtained prepolymer into a polymerization reactor, hydrogen, propylene and ethylene were fed. Then, a propylene-ethylene copolymer was obtained by adjusting the polymerization pressure at a polymerization temperature of 75 ° C., a hydrogen concentration of 0.03 mol%, and an ethylene concentration of 0.13 mol%.
The obtained polypropylene polymer (PP3: random polypropylene) contained 0.5% by weight of ethylene-derived units and had an MFR of 2.5 g / 10 min.

・ Higher fatty acid ester (A) ・ ・ ・ Kao Co., Ltd., trade name Electro stripper TS-5: stearate monoglyceride ・ single hindered phenolic antioxidant (B-1) ・ ・ ・ ADEKA Co., Ltd., trade name Adecastab AO -80: (3,9-bis [1,1-dimethyl-2- [β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2,4,8,10 -Tetraoxaspiro [5,5] Undecane / single hindered phenolic antioxidant (B-2) ... Cytec Industries, Inc., trade name Sianox 1790: 1,3,5-Tris- (4-t-) Butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate-phosphorus antioxidant (C-1) ... BASF, trade name Irgaphos 168: Tris (2,4-di-t-butylphenyl) Phosphite-phosphorus antioxidant (C-2) ... ADEKA Co., Ltd., trade name Adecastab HP-10: 2,2-methylbis (4,6-di-t-butylphenyl) 2-ethylhexylphosphite. Phenolic antioxidant (D-1) ... BASF, trade name Irganox 1010: Tetrax [Methyl-3 (3', 5'-di-t-butyl-4-hydroxyphenyl) propionate] Methyl phosphorus Antioxidant (D-2): ADEKA Co., Ltd., Adecastab PEP-36: Bis (2,6-t-butyl-4-methylphenyl) pentaerythrityldiphosphite)
-Phenyl-based antioxidant (D-3): Sumitomo Chemical Co., Ltd., trade name Sumilyzer GP: 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4-) Hydroxy-5-t-butylphenyl) propoxy] dibenzo [d, f] [1,3,2] dioxaphosphepine The phenol-based antioxidant (D-1) is both hindered phenol-based antioxidants. The phosphorus-based antioxidants (D-2) and (D-3) are phosphorus-based antioxidants other than the phosphorus-based antioxidants represented by the chemical formula (I) or the chemical formula (II). Note that (D-3) is a so-called phenol phosphorus-based antioxidant.
・ Crystal nucleating agent (E-1) ・ ・ ・ BASF, trade name IRGACLEAR XT386: 1,3,5-tris (2,2-dimethylpropanamide) benzene ・ Crystal nucleating agent (E-2) ・ ・・ New Japan Rika Co., Ltd., trade name Gelol E200: 1,3: 2,4-bis-O- (4-methylbenzylidene) -D-sorbitol

<Evaluation>
The obtained resin composition was evaluated as follows. The evaluation results are shown in Tables 1 and 2.
[Yellowness prevention (NOx gas resistance)]
Using a capillary rheometer (Capillograph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd.), the pellets of the resin composition of each example are cylinderd under the conditions of a temperature of 250 ° C., an extrusion speed of 10 m / min, a take-up speed of 100 m / min, and a sampling time of 2 minutes. Extruded from to make strands.
The obtained strands were placed in a glass bottle together with nitrogen oxide gas having a concentration of 2% by volume, sealed, and left in a constant temperature bath at 50 ° C. for 1 week in the sealed state.
Then, the strand was taken out from the glass bottle, the degree of coloring of the strand was visually observed, and the evaluation was made according to the following five criteria.
1: Extremely strong coloring 2: Strongly colored 3: With coloring 4: With slight coloring 5: No coloring

[Burning prevention]
A sample was prepared by adding 0.1% by mass of stearic acid to the pellets of the resin composition.
A cylinder of a capillary rheometer (Capillary Graph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd.) was filled with 20 g of a sample at a temperature of 260 ° C. and left for 10 minutes for heating. Then, it was extruded from the cylinder at an extrusion speed of 30 mm / min to prepare a strand.
The obtained strands were cut into pellets and extruded again using a capillary rheometer under the conditions of a temperature of 260 ° C. and an extrusion speed of 30 mm / min to prepare reextruded strands.
The state of discoloration of the re-extruded strand was visually observed and evaluated according to the following criteria.
1: Visible black particles of 0.2 mm or more are seen in the strand, and there is discoloration. 2: No visible black particles of 0.2 mm or more are seen in the strand, and there is no discoloration.

[Prevention of black spots during injection molding]
The pellets of the resin composition were placed in a constant temperature and humidity oven at a temperature of 75 ° C. and a humidity of 80%, taken out after 24 hours, and further dried in a dryer set at 80 ° C. for 1 hour. The dried pellets were injection molded using an injection molding machine (Sumitomo Heavy Industries, Ltd., SE230HY). At that time, the pellets were allowed to stay in a cylinder set at 250 ° C. and in a hot runner for 1 hour, and then, under the conditions of an injection speed of 250 mm / s and a mold temperature of 10 ° C., 10 pieces of 6.5 g of resin was added per piece. Injection molding was performed in a second cycle (6 pieces per shot). As a result, 480 injection-molded products were obtained.
Of the 480 injection-molded products, those having black spots (visible black particles of 0.2 mm or more) were counted, and the number ratio (%) of the injection-molded products having black spots was determined and used as the black spot generation rate. The smaller the black spot generation rate, the better the black spot generation prevention property.

[Antioxidant]
Using a capillary rheometer (Capillary Graph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd.), 20 g of pellets of the resin composition was preheated in a cylinder at a temperature of 260 ° C. for 3 minutes and then extruded at 50 mm / min to obtain strands. The obtained strands were cut into pellets and extruded again under the same conditions as described above to obtain strands. The obtained strands were cut into pellets.
MFR (JIS K7210-1, temperature 230 ° C., load 2.16 kg) was measured for the strand pellets obtained in the first extrusion and the strand pellets obtained in the second extrusion. Then, the MFR increase rate was calculated from the following formula.
MFR increase rate (%) = ((MFR2-MFR1) / MFR1)) × 100
Here, MFR1 is the MFR measured for the pellets of the strands obtained in the first extrusion, and MFR2 is the MFR measured for the pellets of the strands obtained in the second extrusion.
The smaller the MFR increase rate, the higher the antioxidant property.

[transparency]
Using an injection molding machine (FANUC ROBOSHOT S2000i manufactured by FANUC Co., Ltd.), the molten resin temperature was set to 200 to 230 ° C, the mold temperature was 40 ° C, the average injection speed was 200 mm / sec, and the holding time was 40 seconds, according to JIS K6921-2. A small square plate (type D1) having a thickness of 1.0 mm specified in JIS K7152-3 was formed under the condition that the total cycle time was 60 seconds. Using this as a test piece, the haze was measured by a haze measuring device (HM-150 type manufactured by Murakami Color Technology Research Institute Co., Ltd.) according to JIS K7136. The smaller the haze value, the better the transparency.

<Result>
The resin compositions of Examples 1 to 6 containing 0.03 parts by mass or more of each of the one-sided hindered phenolic antioxidant (B) and the phosphorus-based antioxidant (C) are coexisting with higher fatty acid esters. Nevertheless, it was excellent in burn prevention and black spot prevention. Further, the resin compositions of Examples 1 to 6 were also excellent in anti-yellowing property and anti-oxidation property.
The resin composition of Comparative Example 1 containing both the hindered phenolic antioxidants instead of the one-sided hindered phenolic antioxidant (B) had insufficient anti-yellowing property.
The resin composition of Comparative Example 2 containing a phosphorus-based antioxidant other than the phosphorus-based antioxidant (C) instead of the phosphorus-based antioxidant (C) had insufficient anti-burning property and black spot generation prevention property. ..
The resin composition of Comparative Example 3 containing only a phosphorus-based antioxidant having a one-sided hindered phenol structure as an antioxidant was insufficient in anti-burning property and anti-black spot generation property.
The resin composition of Comparative Example 4 containing a phosphorus-based antioxidant (C) as an antioxidant and a phosphorus-based antioxidant having a one-sided hindered phenol structure had insufficient anti-burning properties.
Comparison in which both the one-sided hindered phenolic antioxidant (B) and the phosphorus-based antioxidant (C) are contained, but the content of the one-sided hindered phenolic oxide (B) is less than 0.03 parts by mass. The resin composition of Example 5 had insufficient antioxidant properties.
Comparative Example 6 containing both the one-sided hindered phenolic antioxidant (B) and the phosphorus-based antioxidant (C), but the content of the phosphorus-based antioxidant (C) was less than 0.03 parts by mass. The resin composition of No. 1 had insufficient antioxidant properties.

Claims (5)

A higher fatty acid ester which is an esterified product of a polyolefin and a saturated fatty acid having 10 to 30 carbon atoms, a single hindered phenolic antioxidant, and a phosphorus-based antioxidant represented by the following chemical formula (I) or the following chemical formula (II). And contains,
It does not contain phosphorus-based antioxidants other than the compounds represented by the following chemical formula (I) or the following chemical formula (II).
The content of the higher fatty acid ester is 0.1 to 1.0 part by mass with respect to 100 parts by mass of the polyolefin, and the content of the one-sided hindered phenolic antioxidant is 0.03 to 0 with respect to 100 parts by mass of the polyolefin. .3 A part by mass of the polyolefin resin composition, wherein the content of the phosphorus-based antioxidant is 0.03 to 0.3 parts by mass with respect to 100 parts by mass of the polyolefin.

In the formula (I), a is an integer of 1 to 3.
^{R 1} and R ² in the formula (II) are independently hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, and the number of carbon atoms. An alkylcycloalkyl group according to any one of 6 to 12, an aralkyl group according to any one having 7 to 12 carbon atoms, or a phenyl group.
R ³ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkylcycloalkyl group, an aralkyl group or a phenyl group. When R ³ is an aralkyl group or a phenyl group, at least one hydrogen atom of the aromatic ring may be substituted with a hydroxy group.
X represents a sulfur atom or a -CHR ⁴ - is a radical ^{(R 4} is a hydrogen atom, or an alkyl group having 1 to 8 carbon atoms, or any cycloalkyl group having a carbon number of 5-8.). The polyolefin resin composition according to claim 1, wherein the polyolefin is polypropylene. When a small square plate with a thickness of 1.0 mm specified by JIS K7152-3 is molded, JIS
The polyolefin resin composition according to claim 1 or 2, wherein the haze measured based on K7136 is 50% or less. The higher fatty acid esters include stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid monosorbitate, stearyl stearate, palmitate monoglyceride, palmitate diglyceride, palmitate triglyceride, palmitate monosorbitet, and palmitate stearyl. Behenic acid monoglyceride, behenyl behenate, pentaerythritol monostearate, pentaerythritol tetrastearate, pentaerythritol tetrapelargonate, propylene glycol monostearate, palmityl palmitate, butyl stearate, methyllaurate, isopropyl palmitate, biphenyl The polyolefin resin composition according to any one of claims 1 to 3, which is one or more selected from biphenate, sorbitan monostearate, and 2-ethylhexyl stearate. A molded product containing the polyolefin resin composition according to any one of claims 1 to 4.