JPH04285645A - Transparentizing agent and composition of polyolefin - Google Patents

Abstract

PURPOSE:To obtain an odorless transprentizing agent, useful for a polyolefin, composed of a naphthyl-substituted sorbitol derivative, excellent in transparency, capable of providing molded products suitable as food containers, packaging materials, etc., by blending with the polyolefin. CONSTITUTION:A transparentizing agent is composed of 1,3:2,4-bis(naphthylmethylene)sorbitol (preferably a beta-naphthyl-substitution product), expressed by the formula and obtained by carrying out a method for condensing reaction of naphthaldehyde with sorbitol at about 2:1 molar ratio using an acid catalyst, etc., and useful for a polyolefmn. A polyolefinic composition is prepared by blending 100 pts.wt. polyolefin, especially homopolymer of the propylene and a copolymer of the propylene with other alpha-olefins (in an amount of <=50wt.%) with 0.01-1 pt.wt., preferably 0.05-0.5 pt.wt. aforementioned transparentizing agent and, as necessary, other transparentizing agents, dispersing agents, lubricants, antistatic agents, germicides, ultraviolet light absorbers, etc. The above-mentioned composition is capable of providing a material suitable especially for food containers, packaging materials, medical equipment, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clarifying agent that imparts transparency to polyolefins, and in particular provides polyolefin compositions suitable for use as materials for food containers, medical instruments, and the like.

0002

[Prior Art and its Problems] Polyolefins have particularly excellent mechanical, thermal, chemical, and electrical properties as well as moldability, so they are used as a main raw material in the plastics industry for various purposes, such as films, It is used in large quantities in a wide range of fields, including packaging materials such as sheets, containers, and pipes, miscellaneous goods containers, and industrial parts. However, since crystalline polyolefins generally have poor transparency in molded products, their applications are limited.

[0003] Therefore, various nucleating agents have been provided in order to improve the transparency of such polyolefins. Among them, as a nucleating agent for sorbitol compounds, for example, benzylidene sorbitol (Japanese Patent Publication No. 51-2
2740) and alkyl-substituted benzylidenesol beetles (Japanese Patent Publication No. 55-12460, Japanese Patent Publication No. 61-5498), but the former does not improve transparency sufficiently, and the latter does not. Although it is quite good, it is accompanied by the generation of odor, which is a problem especially for polyolefins used in food containers, packaging materials, etc.

0004

[Means for Solving the Problems] The present inventor has conducted extensive research in order to solve the above problems. As a result, the present invention was developed based on the knowledge that among sorbitol compounds, naphthyl-substituted sorbitol compounds are particularly effective as nucleating agents for polyolefins to improve transparency, and also significantly reduce odor generation. This is what we have come to offer.

That is, according to the present invention, the following formula

A polyolefin clarifying agent represented by the following formula is provided. Further, according to the present invention, the above formula is applied to 100 parts by weight of polypropylene.

A polyolefin composition containing 0.01 to 1 part by weight of a clarifying agent represented by the following formula is provided.

The polyolefin to which the clarifying agent of the present invention is applied is generally a polymer of ethylene or propylene, with homopolymers of propylene and copolymers of propylene and other α-olefins being particularly preferred. Here, other α-olefins include, for example, ethylene, 1
-Butene and the like are used in an amount of 50% by weight or less, which does not impair the effects of the present invention. Further, the copolymer of propylene and other α-olefin may be any of a random copolymer, a block copolymer, and a graft polymer. Furthermore, blends of polypropylene with other α-olefin polymers, such as other α-olefin homopolymers such as ethylene and 1-butene, or copolymers of these other α-olefins, may also be used. This blending amount is within a range that does not impair the present invention, and the other α-olefin polymer to be blended is generally within a range of 20 parts by weight or less.

The following formula of the present invention

Naphthyl-substituted derivatives of sorbitol as shown in formula 3 are compounds known as paint components for imparting thixotropy (UK Patent No. 14308
No. 66). The sorbitol derivative used as a polyolefin clarifying agent in the present invention is 1.3,
It is 2,4-bis(naphthylmethylene) sorbitol and has an α-naphthyl substituted product and a β-naphthyl substituted product, and the β-naphthyl substituted product is particularly effective. Furthermore, such naphthyl-substituted sorbitol compounds can also be used in a substituted form in which an alkyl group or the like is bonded to the naphthyl group.

The above-mentioned sorbitol derivative of the present invention is
It may be manufactured by any method. A particularly simple production method includes a condensation reaction between naphthylaldehyde and sorbitol using an acid catalyst. The reaction moles of naphthylaldehyde and sorbitol in this reaction are 2
: Preferably close to 1. In addition, the reaction solvent, acid catalyst, reaction conditions, treatment conditions after the reaction, product isolation conditions, etc. were the same as those used in the conventional production of 1,3,2,4-bis-(benzylidene)sorbitol. They may be selected and adopted as appropriate. In addition, in the above reaction, depending on the reaction ratio of naphthylaldehyde and sorbitol, reaction conditions, and purification conditions, 1,3,2,4-bis(naphthylmethylene)sorbitol may contain isomers, mono- and/or tri-(naphthylmethylene)sorbitol. Although some may be present as by-products, the presence of these by-products does not adversely affect the transparency of the polyolefin, which is the objective of the present invention.

In the present invention, polyolefin 100
By blending the clarifying agent in an amount of 0.01 to 1 part by weight, preferably 0.05 to 0.5 part by weight, a polyolefin composition with good transparency can be obtained. That is, when the amount of the clarifying agent of the present invention is less than 0.01 part by weight based on the polyolefin, sufficient transparency cannot be obtained, and when the amount exceeds 1 part by weight, the transparency is impaired. This is not desirable because of the possibility. The polyolefin composition of the present invention may contain other additives such as clarifying agents, dispersants, bactericidal agents, ultraviolet inhibitors, neutralizing agents, lubricants, antistatic agents, and antioxidants to achieve the effects of the present invention. It can also be blended within the range that does not cause any damage.

The polyolefin composition of the present invention can be prepared by known means such as a Henschel mixer, and can also be obtained as extruded pellets by heating and kneading with a screw extruder or the like.

[0011]

According to the present invention, it is possible to obtain a molded article that has good transparency and hardly produces any odor. Therefore, the polyolefin composition of the present invention is extremely useful, particularly as a material for radiation sterilization, for example, in applications such as food containers, packaging materials, and medical instruments.

0012

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 (Manufacture of clarifying agent) Solvitol (5.47 g) and 2-naphthylaldehyde (9.3 g) were added to benzene (200 ml).
7 g) and p-toluenesulfonic acid monohydrate (0.2
0 g) was added, and the mixture was heated on an oil bath with stirring for 5 hours to remove the water produced by azeotropic distillation. After distilling off benzene under reduced pressure, ethanol (200 ml) was added to the residue.
Stir overnight at room temperature. Filter the solid and add ethanol (3
00ml) and dried. The solid was dissolved in water (200ml
) and neutralized with an aqueous sodium carbonate solution. Filter the solid again and add water (500 ml) then ethanol (2
00ml) to obtain a white solid (11.77g) with a melting point of 263-265°C.

Elemental analysis of the obtained white solid showed values of C73.60% and H5.77%, and the calculated value for C28H26O6 was C73.35.
%, H5.72%. Its infrared absorption spectrum showed a wide absorption based on OH at 3100 to 3650 cm, an absorption based on CH at 2800 to 3000 cm, and an absorption based on naphthalene rings at 1600 cm. In addition, when we measured its mass spectrum, m/e45
Peak corresponding to M+ at 8, C10H at m/e156
7 peak corresponding to CO+, C10 at m/e128
Peak corresponding to H8, C10H7 at m/e127
A peak corresponding to + was shown. Further in DMSO
When the 1H-nuclear magnetic resonance spectrum was measured, the chart shown in the figure was obtained, with a peak based on the 14 protons of the naphthalene ring at 7.5 to 8 ppm, and a peak based on the two methine substituted on the naphthalene ring at 5.9 ppm. Proton, 3.3~
A peak based on 10 protons of the sorbitol chain was shown at 5 ppm.

From these results, the white solid obtained was 1
- It became clear that it was 3,2,4-bis(2-naphthylmethylene) sorbitol. The yield was 85.
It was 6%.

(Preparation of polypropylene composition) 1,3,2,4-bis(2-
A polypropylene composition was prepared by blending (naphthylmethylene) sorbito into the polypropylene described below together with a stabilizer. For comparison, a polypropylene composition was similarly prepared using a conventionally known clarifying agent (nucleating agent). The types and symbols of the polypropylene, clarifying agent, and stabilizer used are as follows. (1) Polypropylene (manufactured by Tokuyama Soda Co., Ltd.: powder) Ethylene-propylene random copolymer (ethylene content: 2.0% by weight, melt flow rate: 20g/10min) (2) Nucleating agent A: Bis(4) -t-butylphenyl) sodium phosphate B: pt-butylbenzoate aluminum C: 1.3,
2,4-dibenzylidene sorbitol D: 1,3,2,
4-di(p-methylbenzylidene) sorbitol E: 1,3,2,4-bis(2-naphthylmethylene) sorbitol (3) Stabilizer F: Tris(2,4-di-t-butylphenyl) phosphite G: Tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate H: Calcium stearate

[0017] Additionally, polypropylene compositions (premixed,
The preparation method for pelletization, the method for preparing test samples, and the method for testing (confirming) the effectiveness were performed as described below, and the results are shown in Table 1. (1) Nucleating agents are added to 100 parts by weight of premixed polypropylene in the proportions shown in Table 1, and 0.07 parts by weight of F is added as an antioxidant to prevent deterioration during processing. ,
0.03 parts by weight of G and 0.1 parts by weight of H as a neutralizing agent were mixed together in a Henschel mixer. (2) Pelleting the above mixture using a 50 mmφ extruder (full flight type screw: L/D=28, with vent) at a cylinder temperature of 230°C and a screw rotation of 88 r.p.m. p. Pelletized at m. (3) Preparation of test sample The above pellets were molded using a 50 ton injection molding machine under general molding conditions (cylinder temperature: 230°C, mold temperature: 40°C).
℃), a 1 mm thick molded plate (5
0 mm x 15 mm x 1 mm). (4) Effect test (a) Transparency Haze (%) was measured on a 1 mm thick injection molded plate in accordance with JIS K7105. (b) Odor test and evaluation rank 300 ml of distilled water and 50 g of the above pellets were placed in a 500 ml eggplant-shaped flask equipped with a condenser, and boiled for 30 minutes while cooling water was passed through the condenser. Next, the beaker was boiled with the cooling water turned off, and the steam generated from the top of the condenser was received by holding the beaker upside down, and the odor was confirmed by a panel of five people. The result is the following 6
The odor intensity was determined in stages and an evaluation rank was determined. (0: Not felt, 1: Slightly felt, 2: Slightly felt, 3: Strongly felt, 4: Very strongly felt, 5: Extremely felt)

[Table 1]

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the 1H-nuclear magnetic resonance spectrum of 1,3,2,4-bis(naphthylmethylene)sorbitol produced in Examples.

Claims (2)

[Claims] [Claim 1] The following formula [Chemical formula 1] Clarifying agent for polyolefins shown in 2. A polyolefin composition comprising 0.01 to 1 part by weight of the clarifying agent according to claim 1 per 100 parts by weight of the polyolefin.