JP2813892B2 - Food packaging containers - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a food packaging container comprising a polyolefin resin composition having improved odor and color tone.

[Prior Art] A method of adding an inorganic filler for the purpose of improving properties such as rigidity, impact resistance and heat resistance of a polyolefin has been widely adopted and partially used as a food packaging container.

However, when an inorganic filler is added to polyolefin, an unpleasant odor is generated, the color tone is deteriorated, and the thermal stability is reduced. In particular, when sterilizing the container with the contents at a high temperature, or when heating and cooking in a microwave oven, etc.
Since a more unpleasant odor is generated, it is not satisfactory as a food packaging container, and improvement thereof has been desired.

Therefore, a method for improving the odor of a food packaging container has been proposed (JP-A-63-179943), but the odor of the container is not sufficiently improved, and the color of the container is poor. .

[Problems to be Solved by the Invention] Under such circumstances, the problem to be solved by the present invention is to solve the above-mentioned disadvantages of the prior art, and a specific phenolic antioxidant is added to a polyolefin containing an inorganic filler. Another object of the present invention is to provide a food packaging container having improved odor and color tone by using a resin composition to which a lubricant and / or an antistatic agent are added.

[Means for Solving the Problems] The present inventors have conducted intensive studies to solve the above problems, and as a result,
The present invention has been reached.

That is, the present invention provides a composition comprising 100 parts by weight of polyolefin and 1 to 120 parts by weight of an inorganic filler, further comprising: (i) β- (4-hydroxy-3-t-butyl-5-alkylphenyl) propionic acid Esters, hindered phenols having an isocyanuric acid ester group, 1,
3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene and the following general formula (I) (Wherein, R ₁ represents an alkyl group having 1 to 3 carbon atoms) at least one phenolic antioxidant selected from phenol compounds represented by the following formula: 0.01 to 2.0 parts by weight per 100 parts by weight of polyolefin; And (ii) (a) the following general formula (II) R ₂ —CO—NH— (CH ₂ ) _n —NH—CO—R ₂ (II) (wherein R ₂ is an alkyl group having 5 to 21 carbon atoms) Or an alkenyl group, and n represents an integer of 1 to 6.) or the following general formula (III): R ₃ —CONH ₂ (III) (wherein, R ₃ is an alkyl group or an alkenyl group having 5 to 21 carbon atoms) And / or (b) at least one lubricant selected from the group of compounds represented by the following general formula (IV): Wherein R ₄ is an alkyl group having 8 to 18 carbon atoms, an alkenyl group or an acyl group represented by R′CO— (R ′ is a saturated or unsaturated aliphatic carbon chain), and p and q are 2 ≦ p +
An integer satisfying q ≦ 10, Z is a hydrogen atom or an acyl group represented by R ₅ CO—, and R ₅ is an alkyl group or an alkenyl group having 7 to 17 carbon atoms. ),
At least one selected from the group consisting of lower alcohol esters of fatty acids and polyhydric alcohol esters of fatty acids
The present invention relates to a food packaging container comprising a resin composition containing 0.01 to 5.0 parts by weight of a kind of antistatic agent with respect to 100 parts by weight of an inorganic filler.

After examining the cause of the deterioration of the odor of the food packaging container, the mixture of the polyolefin and the antioxidant and the inorganic filler was kneaded at a high temperature, and the obtained resin composition was thermoformed, or the food packaging container was further molded. When heating,
It has been found that the inorganic filler causes some reaction with the polyolefin and / or the antioxidant, and the deterioration of the polyolefin and / or the decomposition of the antioxidant worsens the odor of the food packaging container and increases the colorability of the container. .

The present invention is to improve the odor and color of food packaging containers,
Select a specific phenolic antioxidant that has high performance to prevent degradation of polyolefins and does not easily react with inorganic fillers, and a specific phenolic antioxidant that does not deteriorate the odor of the container even if the antioxidant decomposes Further, it is based on the finding that the odor and the color tone of the food packaging container can be significantly improved by selecting a compound that suppresses the reaction between the specific phenolic antioxidant and the inorganic filler. is there.

 Hereinafter, the present invention will be described in more detail.

The polyolefin used in the present invention is a homopolymer of α-olefin such as ethylene, propylene, butene-1, hexene-1, 4-methyl-pentene-1, or a random or block copolymer composed of two or more thereof. Yes, polyethylene, polypropylene, polybutene-1, polyisobutene, poly-3-methyl-butene-
1, poly-4-methyl-pentene-1, ethylene-propylene copolymer, ethylene-butene-1 copolymer, propylene-4-methyl-pentene-1 copolymer, propylene-butene-1 copolymer, Ethylene-propylene-butene-1 copolymer, decene-1--4-methyl-pentene-
One copolymer is exemplified, and these are used alone or in combination. Further, a mixture of these polyolefins and a synthetic rubber can be used depending on the application.

Further, as the inorganic filler in the present invention, talc,
Mica, wollastonite, calcium carbonate, barium sulfate, magnesium carbonate, clay, alumina, silica, synthetic zeolite, carbon fiber, glass fiber, metal fiber, silica sand, stone, carbon black, titanium oxide, magnesium hydroxide, asbestos , Zeolite, diatomaceous earth, sericite, shirasu, calcium hydroxide and the like, and these may be used alone or in combination.

Of these, talc, mica, calcium carbonate, glass fiber, wollastonite and the like are preferred. Talc is particularly preferred.

The amount of the inorganic filler is 1 to 120 parts by weight, preferably 5 to 100 parts by weight, based on 100 parts by weight of the polyolefin.
If the amount is less than 1 part by weight, the effect of improving the mechanical properties and heat resistance is small. If the amount is more than 120 parts by weight, thermoforming is difficult and it is difficult to form a container having a uniform thickness.

Specific phenolic antioxidants used in the present invention include β- (4-hydroxy-3-t-butyl-5-alkylphenyl) propionic esters, hindered phenols having an isocyanuric ester group, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene and general formula (I) (In the formula, R ₁ represents an alkyl group having 1 to 3 carbon atoms.) At least one phenolic antioxidant selected from phenol compounds represented by the following formulas, for example, tetrakis [methylene-3- (3, 5-di-t-butyl-
4-hydroxyphenyl) propionate] methane, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris (3,5
-Di-t-butyl-4-hydroxybenzyl) -2,4,6
-Trimethylbenzene, tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) -propionyloxy]-
1,1-Dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane and the like are preferable.

The content of phenolic antioxidant is polyolefin 10
0.01 to 2.0 parts by weight, preferably 0.03 to 1.
0 parts by weight. When added in an amount of 2.0 parts by weight or more, it may cause adverse effects such as smoking during molding and bleeding on the surface of the container, and is economically disadvantageous. 0.01
The effect of the present invention cannot be sufficiently achieved with a blending amount of not more than parts by weight.

A lubricant and / or an antistatic agent is used as a compound for suppressing the reaction between the inorganic filler and a specific phenolic antioxidant.

Lubricants used in the present invention, (a-1) the following general formula _{(II) R 2 -CO-NH-} (CH 2) n -NH-CO-R 2 (II) ( wherein, R ₂ is the number of carbon atoms Represents an alkyl group or an alkenyl group of 5 to 21, and n represents an integer of 1 to 6.), (a-2) the following general formula (III) R ₃ —CONH ₂ (III) (wherein R ₃ is It represents an alkyl group or an alkenyl group having 5 to 21 carbon atoms.) One or more lubricants selected from the group of compounds represented by the formula:

Preferred specific examples include methylenebisstearic acid amide, ethylenebisstearic acid amide, ethylenebisoleic acid amide, hexamethylenebisstearic acid amide, lauric acid amide, stearic acid amide, oleic acid amide, behenic acid amide, erucic acid amide, and the like. Is mentioned.

 Particularly, an amide of a saturated fatty acid is preferred.

The antistatic agent used in the present invention is represented by the following general formula (IV): Wherein R ₄ is an alkyl group having 8 to 18 carbon atoms, an alkenyl group or an acyl group represented by R′CO— (R ′ is a saturated or unsaturated aliphatic carbon chain), and p and q are 2 ≦ p +
An integer satisfying q ≦ 10, Z is a hydrogen atom or an acyl group represented by R ₅ CO—, and R ₅ is an alkyl group or an alkenyl group having 7 to 17 carbon atoms. And (b-2) lower alcohol esters of fatty acids; and (b-3) polyhydric alcohol esters of fatty acids. Preferred specific examples include: Glycerin monostearate, polyoxyglycerin monostearate and the like can be mentioned.

The amount of the lubricant and / or antistatic agent is inorganic filler
0.01 to 5.0 parts by weight, preferably 0.05 to 100 parts by weight
2.0 parts by weight. When added in an amount of 5.0 parts by weight or more, the odor of the additive becomes conversely strong, which may cause an unpleasant odor, and is economically disadvantageous. If the amount is less than 0.01 parts by weight, the effects of the present invention cannot be sufficiently achieved.

In the present invention, a phosphorus-based antioxidant may be added in order to improve processing stability and thermal oxidation stability.

Examples of the phosphorus-based antioxidant include distearylpentaerythritol diphosphite, tris (2,4-di-t-butylphenyl) phosphite, and bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite. Phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenyldiphosphonite, and trinonylphenyl phosphite.

The addition amount of the phosphorus-based antioxidant is 0.01 to 1.0 part by weight, preferably 0.03 to 0.5 part by weight, based on 100 parts by weight of the polyolefin.

In addition, other additives such as a neutralizing agent, an antioxidant, a light stabilizer, an ultraviolet absorber, a heavy metal deactivator, a plasticizer, a nucleating agent, and an anti-blocking agent are included in the present invention as long as the properties are not impaired. Agents, pigments (including titania), foaming agents, fungicides and the like can be added.

The food packaging container of the present invention can be manufactured by the same method as manufacturing a general plastic container.

For example, after a polyolefin powder and an inorganic filler, a phenolic antioxidant, a lubricant and / or an antistatic agent, etc. are stirred with a Hellciel mixer or the like, they are kneaded using an extruder or a kneader such as a Banbury mixer to form pellets. The extruder is then introduced into a T-die extruder, extruded into a sheet, and then formed into a desired shape by thermoforming, or directly into a container from pellets by an injection molding machine. Manufacture packaging containers. Add foaming agent and extrude from pellet into sheet, 1.1 ~ 2
It is also possible to thermoform into a food packaging container after foaming to 0 times.

Further, a food packaging container can be obtained by thermoforming a multilayer coextruded sheet, for example, a sheet composed of the polyolefin resin composition / polyvinylidene chloride / polypropylene or the polyolefin resin composition.

[Examples] In order to explain the present invention more specifically, examples and comparative examples are shown below, but the present invention is not limited to these examples.

Example 1 To 60 parts by weight of polypropylene homopowder (melt flow index: 0.8 g / 10 minutes) and 40 parts by weight of talc, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] was added. Methane (Sumilyzer BP-101) 0.2 parts by weight, glycerin monostearate
0.15 parts by weight and 0.05 parts by weight of calcium stearate were added, mixed with a Hensiel mixer, and then pelletized at 250 ° C. with an extruder. The pellet was extruded into a sheet having a thickness of 0.6 mm by an extruder equipped with a T-die, and then thermoformed from the sheet to obtain a container having a length of 16 cm, a width of 10 cm and a depth of 2.5 cm. After cutting the obtained container into small pieces of several mm square, 10 g was placed in a container with a glass lid having a capacity of 200 ml, heated in an oven set at 150 ° C. for 10 minutes, and further conditioned at 60 ° C. for 30 minutes. The odor intensity of the gas phase was quickly taken out and evaluated.

The evaluation of the odor intensity was carried out by a five-level evaluation by five judges, and the average odor value was obtained. The odor of this container was 2.4.

 However, the criteria for determining the odor were as follows.

 1; very low odor intensity (almost no odor), 2; low odor intensity (slightly odor), 3; medium odor intensity (obvious odor), 4; strong odor intensity (strong odor), 5; very low odor intensity Strong (unbearable).

Also, remove the sheet from the container and place it in YI (Yellowness I
ndex) (based on JISK 7103). The YI value was 5. The smaller the value, the better the color tone.

In addition, the volatile components generated at 150 ° C in food packaging containers are analyzed using a fully automatic headspace analysis system consisting of a gas chromatograph (GC-9APF, manufactured by Shimadzu) and a headspace sampler (HSS-2A, manufactured by Shimadzu). The measurement was performed as follows.

(1) Cut the container into small pieces of several mm square, and add 0.5 g to a capacity of 20 ml.
Was filled in a vial glass bottle under a nitrogen atmosphere, and set in a head spacer sampler.

(2) After heating the glass bottle at 150 ° C. for 60 minutes, 0.8 ml of gas in the gas phase was collected and provided for analysis.

(3) Analysis conditions for glass chromatography Column: HiCap-CBP1 (Shimadzu Corporation, inner diameter: 0.25 mm, length: 25 m) Column temperature: 60 ° C → 5 ° C / min → 230 ° C (heating measurement) Injection temperature: 300 ° C detection Temperature: 300 ° C. Carrier gas: He The measurement results are shown in FIG. 1, but volatile components (decomposition components) were hardly detected.

Comparative Example 1 The procedure of Example 1 was repeated, except that glycerin monostearate was not added. The results are shown in Table 1.

When the volatile components in this container were analyzed, a large amount of volatile components (decomposed components) was detected (FIG. 2). Good response to worse odor.

Comparative Example 2 In Example 1, tetrakis [methylene-3- (3,
5-Di-t-butyl-4-hydroxyphenyl) propionate] Same as Example 1 except that methane was changed to 2,6-di-t-butyl-4-methylphenol (Sumitomo Chemical, Sumilizer BHT) It was done. First result
It is shown in the table. Further, when the volatile components in this container were analyzed, a large amount of volatile components (decomposed components) was detected (third component).
Figure). Good response to worse odor.

Comparative Example 3 In Example 1, tetrakis [methylene-3- (3,
0.1 part by weight of tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane instead of 0.2 part by weight of 5-di-t-butyl-4-hydroxyphenyl) propionate] methane And 0.1 parts by weight of 2,6-di-t-butyl-4-methylphenol were added. The results are shown in Table 1.

When the volatile components in this container were analyzed, a large amount of volatile components (decomposed components) was detected (FIG. 4). Good response to worse odor.

Example 2 The procedure of Example 1 was repeated, except that glycerin monostearate was changed to ethylene bisstearic acid amide. The results are shown in Table 1.

When the volatile components in this container were analyzed, almost no volatile components were detected (FIG. 5).

Example 3 0.2 parts by weight of tris- (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1.1 parts by weight of ethylenebisstearic acid amide, and 80 parts by weight of polypropylene homopowder and 20 parts by weight of talc The procedure was performed in the same manner as in Example 1 except that 0.05 parts by weight of calcium phosphate was added. The results are shown in Table 1.

Examples 4 to 6 The procedure of Example 3 was repeated, except that the type of the lubricant or the antistatic agent was changed. The results are shown in Table 1.

Examples 7 and 8 The same procedure as in Example 3 was carried out except that the type of the phenolic antioxidant was changed. The results are shown in Table 1.

Example 9 Example 9 was carried out in the same manner as in Example 3, except that calcium carbonate was used instead of talc. The results are shown in Table 1.

Comparative Example 4 Example 3 was carried out in the same manner as in Example 3 except that ethylene bisstearic acid amide was not added. The results are shown in Table 1.

[Effects] As is clear from Table 1, a phenolic antioxidant, a lubricant and / or a specific phenolic antioxidant are used for the system of the polyolefin and the inorganic filler.
Alternatively, a food packaging container thermoformed from a resin composition to which an antistatic agent has been added has markedly improved odor and color tone, and as a result, is suitably used as a container that can be sterilized at a high temperature and a container for a microwave oven.

[Brief description of the drawings]

1 is a cas chromatogram according to Example 1 of the present invention, FIG. 2 is a gas chromatogram according to Comparative Example 1 of the present invention, FIG. 3 is a gas chromatogram according to Comparative Example 2 of the present invention, and FIG. FIG. 5 is a gas chromatogram according to Comparative Example 3 of the present invention, and FIG. 5 is a gas chromatogram according to Example 4 of the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification code FI C08K 5:13 5:20 5:17 5:15 3:00) (58) Investigated field (Int.Cl. ⁶ , DB name) ) C08L 23/00-23/36

Claims (1)

(57) [Claims] 1. A composition comprising 100 parts by weight of a polyolefin and 1 to 120 parts by weight of an inorganic filler, further comprising: (i) a β- (4-hydroxy-3-t-butyl-5-alkylphenyl) propionate , Hindered phenols having isocyanurate groups, 1,
3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene and the following general formula (I) (Wherein, R ₁ represents an alkyl group having 1 to 3 carbon atoms) at least one phenolic antioxidant selected from phenol compounds represented by the following formula: 0.01 to 2.0 parts by weight per 100 parts by weight of polyolefin; And (ii) (a) the following general formula (II) R ₂ —CO—NH— (CH ₂ ) _n —NH—CO—R ₂ (II) (wherein R ₂ is an alkyl group having 5 to 21 carbon atoms) Or an alkenyl group, and n represents an integer of 1 to 6.) or the following general formula (III): R ₃ —CONH ₂ (III) (wherein, R ₃ is an alkyl group or an alkenyl group having 5 to 21 carbon atoms) And / or (b) at least one lubricant selected from the group of compounds represented by the following general formula (IV): Wherein R ₄ is an alkyl group having 8 to 18 carbon atoms, an alkenyl group or an acyl group represented by R′CO— (R ′ is a saturated or unsaturated aliphatic carbon chain), and p and q are 2 ≦ p +
An integer satisfying q ≦ 10, Z is a hydrogen atom or an acyl group represented by R ₅ CO—, and R ₅ is an alkyl group or an alkenyl group having 7 to 17 carbon atoms. ),
At least one selected from the group consisting of lower alcohol esters of fatty acids and polyhydric alcohol esters of fatty acids
A food packaging container comprising a resin composition containing 0.01 to 5.0 parts by weight of a kind of antistatic agent with respect to 100 parts by weight of an inorganic filler.