JP2813891B2 - Food containers - Google Patents

Description

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

[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 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, so that there is a problem in using it as a food container. In particular, when the container containing the contents is sterilized at a high temperature or cooked in a microwave oven or the like, a more unpleasant odor is generated, which is not satisfactory as a food container. Was.

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

[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 drawbacks of the conventional technology, and a specific 6-hydroxychromane-based polyolefin containing an inorganic filler is used. An object of the present invention is to provide a food container having an improved odor by using a resin composition to which a compound and a lubricant and / or an antistatic agent are added together.

[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 a polyolefin and 1 to 120 parts by weight of an inorganic filler, further comprising (i) a compound represented by the following general formula (I): (Wherein, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a same or different alkyl group having 1 to 4 carbon atoms, and R ₄ represents an alkyl group having 1 to 16 carbon atoms or Represents an alkenyl group) in an amount of 0.01 to 2.0 parts by weight per 100 parts by weight of polyolefin.
Parts by weight, and (ii) (a) the following general formula (II): R ₅ —CO—NH— (CH ₂ ) _n —NH—CO—R ₅ (II) (wherein, R ₅ represents ₅ to 21 carbon atoms) Wherein n represents an integer of 1 to _6. ) or the following general formula (III): R ₆ -CONH ₂ (III) (wherein, R ₆ is an alkyl group having 5 to 21 carbon atoms) Or an alkenyl group.) And / or (b) at least one lubricant selected from the group of compounds represented by the following general formula (IV): Wherein R ₇ 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 fatty carbon chain), and p and q are 2 ≤p + q
Integer satisfying ≦ 10, Z is an acyl group represented by CO- hydrogen atom or R _8, R ₈ represents an alkyl or alkenyl group of 7 to 17 carbon atoms. ), A resin composition containing 0.01 to 5.0 parts by weight of at least one antistatic agent selected from the group consisting of lower alcohol esters of fatty acids and polyhydric alcohol esters of fatty acids with respect to 100 parts by weight of the inorganic filler. The present invention relates to a food container characterized by comprising a product.

After examining the cause of the deterioration of the odor of the food 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 container was further heated. At that time, it was found that the inorganic filler caused some reaction with the polyolefin and / or the antioxidant, and the odor of the food container deteriorated due to the deterioration of the polyolefin and / or the decomposition of the antioxidant.

The present invention is to improve the odor of food containers, high performance to prevent the degradation of polyolefin, and select a specific 6-hydroxychroman-based compound that does not easily react with the inorganic filler,
Further, based on the finding that the odor of a food container can be remarkably improved by adding a lubricant and / or an antistatic agent as a compound for suppressing the reaction between a 6-hydroxychroman compound and an inorganic filler. It is.

 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. , 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 preferable, and talc is particularly preferable.

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.

Examples of the 6-hydroxychroman compound used in the present invention include various tocopherols of α, β, γ, ζ, ε, η, and δ, a mixture thereof, and 2- (4-methyl-penta-
2,5-dimethyl-substituted and 2,5,8-trimethyl-substituted 3- (3-enyl) -6-hydroxychromans and 2,5,
7,8-tetramethyl substituent, 2,2,7-trimethyl-5-t
-Butyl-6-hydroxychroman, 2,2,5-trimethyl-7-tert-butyl-6-hydroxychroman, 2,2,5
-Trimethyl-6-tert-butyl-6-hydroxychroman, 2,2-dimethyl-5-tert-butyl-6-hydroxychroman and the like. Particularly, the above-mentioned various tocopherols and mixtures thereof are preferable.

The amount of the 6-hydroxychroman compound is 0.01 to 2.0 parts by weight, preferably 100 parts by weight of the polyolefin, preferably
0.03 to 1.0 part by weight. When 2.0 parts by weight or more is added,
This may cause adverse effects such as smoking during molding and bleeding on the surface of the container, 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.

Lubricants used in the present invention, (a-1) the following general formula _{(II) R 5 -CO-NH-} (CH 2) n -NH-CO-R 5 (II) ( wherein, R ₅ 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 ₆ -CONH ₂ (III) (wherein R ₆ 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 ₇ 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 +
integer satisfying q ≦ 10, Z is an acyl group represented by CO- hydrogen atom or R _8, R ₈ represents an alkyl or alkenyl group of 7 to 17 carbon atoms. And (b-2) lower alcohol esters of fatty acids, and (b-3) polyhydric alcohol esters of fatty acids, and at least one antistatic agent selected from the group consisting of:

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 antioxidant include distearyl pentaerythritol 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 container of the present invention can be manufactured by the same method as manufacturing a general plastic container.

For example, polyolefin powder and inorganic filler, 6-
After the hydroxy chroman compound, lubricant and / or antistatic agent, etc. are stirred with a Herciel mixer or the like, they are kneaded using an extruder or a kneader such as a Banbury mixer to form pellets, and then charged into an extruder with a T-die. After extruding into a sheet by thermoforming the sheet into a desired shape,
Alternatively, the food container of the present invention is produced by a method such as molding directly from pellets into a container by an injection molding machine. Add foaming agent and extrude from pellet into sheet, 1.1
It is also possible to thermoform into a food container after foaming up to 20 times.

Further, a food 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 60 parts by weight of polypropylene homopowder (melt flow index 0.8 g / 10 minutes) and 40 parts by weight of talc were added with dl-α-
0.05 parts by weight of tocopherol, 0.15 parts by weight of glycerin monostearate and 0.05 part by weight of calcium stearate were added, mixed with a Henschel mixer, and then pelletized at 250 ° C. with an extruder.

After extruding the pellets into a sheet having a thickness of 0.6 mm with an extruder equipped with a T die, the pellets were thermoformed, and the length was 16 cm.
A container having a width of 10 cm and a depth of 2.5 cm was obtained. The obtained container is several mm
After cutting into small square pieces, 10 g was placed in a 200 ml glass lidded container, heated in an oven set at 150 ° C for 10 minutes, and then adjusted at 60 ° C for 30 minutes. The odor intensity was 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 2.6.

 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).

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

Comparative Example 2 In Example 1, dl-α-tocopherol was replaced with 2,6-
The procedure was performed in the same manner as in Example 1 except that di-t-butyl-4-methylphenol was used. The results are shown in Table 1.

Examples 2 to 5 The same procedures as in Example 1 were carried out except that the type of the lubricant or the antistatic agent was changed as shown in Table 1. The results are shown in Table 1.

Comparative Example 3 In Example 1, dl-α-tocopherol was replaced with 2,6-
Performed in the same manner as in Example 1 except that di-t-butyl-4-methylphenol and tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane were added. Was. The results are shown in Table 1.

[Effects of the Invention] As is clear from Table 1, food containers thermoformed from a resin composition obtained by adding dl-α-tocopherol and a lubricant and / or an antistatic agent to a system of a polyolefin and an inorganic filler have a significantly improved odor. As a result, it is suitably used as a container sterilized at a high temperature and a container for a microwave oven.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 5:15 5:17 5:10)

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 compound represented by the following general formula (I): (Wherein, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a same or different alkyl group having 1 to 4 carbon atoms, and R ₄ represents an alkyl group having 1 to 16 carbon atoms or Represents an alkenyl group) in an amount of 0.01 to 2.0 parts by weight per 100 parts by weight of polyolefin.
Parts by weight, and (ii) (a) the following general formula (II): R ₅ —CO—NH— (CH ₂ ) _n —NH—CO—R ₅ (II) (wherein, R ₅ represents ₅ to 21 carbon atoms) Wherein n represents an integer of 1 to _6. ) or the following general formula (III): R ₆ -CONH ₂ (III) (wherein, R ₆ is an alkyl group having 5 to 21 carbon atoms) Or an alkenyl group.) And / or (b) at least one lubricant selected from the group of compounds represented by the following general formula (IV): Wherein R ₇ 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 ₈ CO—, and R ₈ is an alkyl group or an alkenyl group having 7 to 17 carbon atoms. ), A resin composition containing 0.01 to 5.0 parts by weight of at least one antistatic agent selected from the group consisting of lower alcohol esters of fatty acids and polyhydric alcohol esters of fatty acids with respect to 100 parts by weight of the inorganic filler. A food container comprising a product.