JP3380100B2 - Polyolefin resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyolefin resin composition comprising a polyolefin resin, a sorbitol-based clarifying nucleating agent, and hydantoins, which has excellent transparency and has little odor.

[0002]

2. Description of the Related Art Polyolefin resins have good mechanical properties, heat resistance, chemical resistance, and hygiene.
Food containers, such as food packages, frozen dessert containers, trays,
It is widely used for instant food containers, margarine containers, etc., and medical devices such as syringes, syringes, Spitz tubes, infusion containers, cylinders, etc.

However, in applications such as food containers and medical instruments, it is important to be able to confirm that the contents of the container are not contaminated with dust or other foreign matter, and the correct color tone of the contents depends on the container. It is not preferable to change it.
Therefore, in these applications, it is desired to use a polyolefin resin having good transparency.

In addition, in applications such as food containers and medical instruments, it is essential to have no odor. As a method for improving the transparency of a polyolefin resin, a method of adding a sorbitol derivative is generally widely adopted.

Among the sorbitol derivatives, one having the effect of improving the transparency of the polyolefin resin is 1.
3,2.4-Di-benzylidene sorbitol, 1.3,
2,4-di- (methylbenzylidene) sorbitol, 1
・ 3,2,4-di- (ethylbenzylidene) sorbitol and the like.

Of these, 1,3,2,4-di- (methylbenzylidene) sorbitol and 1,3,2,4-di-
Although the polyolefin resin composition containing (ethylbenzylidene) sorbitol has excellent transparency, it is not satisfactory in terms of odor. The polyolefin resin composition to which 1,3,2,4-di- (ethylbenzylidene) sorbitol is added can barely be used for food containers and medical instruments, but is not sufficiently satisfactory. Also 1,3,2,4-di- (methylbenzylidene)
The polyolefin resin composition to which sorbitol is added has a bad odor and cannot be used for applications such as food containers and medical instruments.

On the other hand, among the sorbitol derivatives, 1
The polyolefin resin composition containing 3,2,4-di-benzylidene sorbitol has a relatively weak odor, but its transparency cannot be said to be good. In general, residual unreacted aldehydes in commercially available sorbitol derivatives have a correlation with the odor (aldehyde odor) of a mixed molded product of a polyolefin resin and a sorbitol derivative, and depending on its application (for example, food container, medical device). It is necessary to remove it as much as possible.

Therefore, in the production of these sorbitol-based clarifying nucleating agents, the catalyst, metal components, unreacted raw materials and the like remaining in the nucleating agent are strictly controlled so that they can be used.

Conventionally, as a countermeasure against odor in sorbitol derivatives, a method of coating a sorbitol composition with a higher fatty acid (see JP-A-57-021440) and a method of treating sorbitols with hydroxylamine (JP-A-SHO). No. 60-032791) is known, but
At present, even if these are used, a polyolefin resin composition satisfying both transparency and odor at the same time has not been obtained.

[0010]

The problem to be solved by the present invention is to solve these problems in the prior art and to provide a polyolefin resin composition having excellent transparency and less odor.

[0011]

Means for Solving the Problems The present inventor has conducted diligent research to solve the above-mentioned problems of a polyolefin resin composition containing a sorbitol derivative, and as a result, a polyolefin resin, a sorbitol-based clarifying nucleating agent and a hydantoin have been obtained. The polyolefin resin composition obtained by mixing the above-mentioned compounds has almost the same transparency as the resin composition comprising the polyolefin resin and the sorbitol-based clarifying nucleating agent, and has much less odor than this. Furthermore, they have found that a polyolefin resin composition excellent in impact resistance, heat resistance, chemical resistance, and hygiene can be obtained, and completed the present invention.

That is, the present invention relates to polypropylene homopoly
Polymer or 100 parts by weight of a polyolefin resin selected from a propylene-ethylene copolymer , 0.01 to 2.0 parts by weight of a sorbitol-based clarifying nucleating agent, and hydantoins.
A polyolefin resin composition comprising 001 to 2.0 parts by weight.

In particular, the sorbitol-based clarifying nucleating agent is a polyolefin resin composition which is a sorbitol derivative represented by the following general formula (1).

[0014]

[Chemical 3] (In the formula, R ¹ and R ² represent a hydrogen atom, a C1-C4 saturated aliphatic alkyl group, a branched alkyl group, or a halogen atom,
R ¹ and R ² may be the same or different. Further, m and n represent integers from 1 to 5, and m and n may be the same or different. )

Further, in particular, hydantoins are polyolefin resin compositions which are compounds represented by the following general formula (2).

[0016]

[Chemical 4] (In the formula, R ³ and R ⁴ represent a hydrogen atom, or an alkyl group, an aryl group, or a cycloalkyl group , and they may form a ring with each other.)

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The polyolefin resin used in the present invention is a polypropylene homopolymer, propylene-
Any ethylene copolymer may be used, or a mixture thereof may be used.

The substituents R ¹ and R ² of the sorbitol derivative represented by the general formula (1) used in the present invention are hydrogen atom, methyl group, ethyl group, n-propyl group, i-propyl group,
Examples thereof include saturated aliphatic alkyl groups such as n-butyl group, i-butyl group and t-butyl group, branched alkyl groups, and halogen atoms such as chlorine atom, bromine atom and fluorine atom.

The hydantoins used in the present invention include, for example, hydantoin, 5-methylhydantoin,
There are 5-ethylhydantoin, 5-isopropylhydantoin, 5,5-dimethylhydantoin, 5,5-diethylhydantoin, 5-phenylhydantoin, 5,5-pentaspirohydantoin, 5,5-hexamethylenespirohydantoin and the like.

The sorbitol-based clarifying nucleating agent used in the present invention is one kind or a mixture of two or more kinds, and the addition amount thereof is 0.01 per 100 parts by weight of the polyolefin resin.
To 2.0 parts by weight, preferably 0.02 to 1.0 parts by weight. If the addition amount is less than 0.01 parts by weight, almost no effect can be obtained in improving the transparency of the molded product, and if the addition amount exceeds 2.0 parts by weight, the effect increases in proportion to the addition amount. Not only that, but the protrusion to the mold during molding becomes severe,
It is not preferable because it causes trouble.

The hydantoins used in the present invention are one kind or a mixture of two or more kinds, and the addition amount thereof is 0.001 to 2.0 with respect to 100 parts by weight of the polyolefin resin.
Parts by weight, preferably 0.001 to 0.2 parts by weight.
If it is added in an amount less than 0.001 part by weight, the effect of improving odor on the molded product is small and it is unsuitable for food containers and medical instruments. If added in excess of 2.0 parts by weight, the transparency of the molded product is low. Is lowered, which is not preferable.

If desired, other additives such as an antioxidant, an ultraviolet absorber, a pigment, a dispersant and a neutralizer may be added to the resin composition of the present invention.

As the antioxidant that can be used in the present invention, tris (2,4-di-butylphenyl) phosphite,
2,6-di-t-butyl-p-methylphenol, n-
Octadecyl-3- (4-hydroxy-3,5-di-t
-Butylphenyl) propionate, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, pentaerythritol-tetrakis (β-lauryl-thiopropionate), dilauryl Examples include thiopropionate.

As the ultraviolet absorber, 2-hydroxy-
4-n-octoxy-benzophenone, 2- (2-hydroxy-3,5-di-t-butyl-phenyl) -5-chlorobenzenetriazole, dimethylsuccinate.2
-(Hydroxy-2,2,6,6, -tetramethyl-1
Typical examples thereof include piperidyl) ethanol condensate.

Further, in order to improve the moldability of the resin composition of the present invention, a peroxide may be added to control the melt flow index.

As the peroxide, 2,5-dimethyl-
2,5-bis (t-butylperoxy) hexane, di-
Typical examples are t-butyl perphthalate and benzoyl peroxide.

The method for producing the polyolefin resin composition of the present invention includes a polyolefin resin, a predetermined amount of a sorbitol-based clarifying nucleating agent and hydantoins, and known additives such as calcium stearate added to the polyolefin resin as desired. Neutralizers such as, antioxidants, ultraviolet absorbers, peroxides, etc. are mixed in a Henschel mixer or other blender, uniformly dispersed, and melt pelletized by an extruder, or a polyolefin resin. A fixed amount of sorbitol-based clearing nucleating agent, hydantoins or one or more of the desired additives uniformly mixed with a known blender was added to the molten resin from the middle during extrusion such as side feed during extrusion. Extrude using an extruder that can be mixed, and add the remaining additives along the way to the side feeder. Contaminating method of melt pelletized in,
Alternatively, the polyolefin resin is extruded using an extruder capable of mixing additives into the molten resin from the middle of extrusion such as side feed, and a predetermined amount of a sorbitol-based clarifying nucleating agent, hydantoins or a desired amount is extruded on the way. A method in which additives are uniformly mixed in a blender in one side feeder or in different side feeders without mixing or in the side feeder according to the form of powder, fibrous body, liquid, etc. and melt pelletizing There is
Either one may be selected.

[0028]

The present invention will be described in more detail with reference to Examples and Comparative Examples. Example 1 Propylene-ethylene random copolymer (230 ° C x
Melt flow index measured at 2.16 kg: 8
g / 10 min. , Ethylene content: 4.0% by weight) 0.35 parts by weight of 1,3,2,4-di-benzylidene sorbitol, 0.01 part by weight of 5,5-dimethylhydantoin, 0.1 part of calcium stearate per 100 parts by weight of powder.
Parts by weight, 0.1 parts by weight of tris (2,4-di-t-butylphenyl) phosphite as an antioxidant, and dimethylsuccinate.2- (4-hydroxy-2,2,6,6) as an ultraviolet absorber. 0.04 parts by weight of a 6-tetramethyl-1-piperidyl) ethanol condensate was added, mixed in a Henschel mixer, and pelletized at an extrusion temperature of about 240 ° C. by an ordinary extruder.

The above pellets were subjected to an injection molding machine at 210 ° C.
Was injection-molded to obtain a flat plate of 160 × 80 × 2 mm, and the haze of the obtained flat plate was measured with a haze meter. In addition, the degree of generation of odor is 200 g for 30 g of pellets.
After sealing in a ml glass bottle and leaving it in a constant temperature bath at 130 ° C. for 1 hour, the presence or absence thereof was evaluated. ◯: No odor, Δ: Slight odor, X: Clearly odor. The results are shown in Table 1.

Examples 2 to 3 Pelletization and injection were carried out in the same manner as in Example 1 except that the kinds and amounts of the sorbitol-based clarifying nucleating agent and hydantoins used in Example 1 were changed as shown in Table 1. Molding was performed and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1 together with the results of Example 1.

Comparative Examples 1 to 2 Pelletization and injection molding were carried out in the same manner as in Example 1 except that the addition amount of 5,5-dimethylhydantoin was changed as shown in Table 1 in Example 1. Evaluation was performed in the same manner as 1. The results are shown in Table 1 together with the results of Example 1.
It can be seen that the composition is inferior in transparency or odor as compared with Examples 1 to 3.

[0032]

[Table 1]

[0033]

EFFECTS OF THE INVENTION The polyolefin resin composition of the present invention contains a sorbitol-based clarifying nucleating agent and a hydantoin compound in combination with a polyolefin resin, so that the transparency is not impaired as is apparent from Examples and Comparative Examples. In addition, the odor can be greatly improved as compared with the case where the sorbitol-based clearing nucleating agent is used alone.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08L 23/00-23/36

Claims (3)

(57) [Claims] 1. A polypropylene homopolymer or a polypropylene homopolymer.
100 parts by weight of polyolefin resin selected from pyrene-ethylene copolymer , sorbitol-based clarifying nucleating agent 0.0
1 to 2.0 parts by weight, hydantoins 0.001 to 2.0
A polyolefin resin composition comprising a part by weight. 2. A sorbitol-based clearing nucleating agent is represented by the general formula (1): (In the formula, R ¹ and R ² represent a hydrogen atom, a C1-C4 saturated aliphatic alkyl group, a branched alkyl group, or a halogen atom,
R ¹ and R ² may be the same or different. Further, m and n represent integers from 1 to 5, and m and n may be the same or different. The polyolefin resin composition according to claim 1, which is a sorbitol derivative represented by the formula (1). 3. Hydantoins are represented by the general formula (2): (In the formula, R ³ and R ⁴ represent a hydrogen atom or a hydrocarbon group such as an alkyl group, an aryl group and a cycloalkyl group, and they may form a ring with each other.) Item 2. The polyolefin resin composition according to Item 1.