JPS60101131A - Additive for polyolefin resin - Google Patents

Abstract

PURPOSE:The titled additive capable of providing a transparent, nonbleeding polyolefin composition, prepared by allowing terephthalic acid to adhere integrally onto the surfaces of particles of (nucleus-substituted) benzylidenesorbitol powder. CONSTITUTION:90-99.1wt% powder or (nucleus-substituted) dibenzylidenesorbitol of the formula (wherein R is H, methyl, ethyl, butyl, Cl, or a 1-3C alkoxy) is added to a suspension obtained by dissolving 10-1wt% terephthalic acid in an aprotic polar solvent (e.g., N-methyl-2-pyrrolidone) and adding a large amount of water or alcohol to the solution, filtered, and drid to obtain an additive for polyolefin resins, comprising (nucleus-substituted) dibenzylidenesorbitol powders having surfaces onto which terephthalic acid adheres integrally.

Description

Detailed Description of the Invention The present invention relates to an additive for polyolefin resin in which terephthalic acid is attached and integrated on the powder surface of dibenzylidene sorbitol or its nuclear substituted product, and by adding the additive to the entire polyolefin resin, extremely transparent properties can be obtained. This results in a polyolefin composition with excellent properties and no bleed.

Polyolefin resins, such as polyethylene resins and polypropylene resins, are often used as film sheet molded products because of their good processability and chemical resistance. However, these resins have poor transparency due to their crystallinity, and have the disadvantage that, for example, when used as a packaging sheet, the contents cannot be seen from the outside. Therefore, many proposals have been made to improve the transparency of this resin. The present inventor previously proposed to completely improve the transparency of polyolefin resin by using dibenzylidene sorbitol as an additive (Japanese Patent Application No. 49-94424, U.S. Pat.
No. 016118), the polyolefin resin and dibenzylidene sorbitol were not compatible with each other, and it was difficult to obtain a homogeneous mixture. It has also been proposed to use dibenzylidene sorbitol in combination with an organic carboxylic acid or its anhydride (JP-A-51-122150). Although this method is effective in increasing the total compatibility of dibenzylidene sorbitol with polyolefin resins, it has the disadvantage that most organic carboxylic acids or their anhydrides tend to sublime and bleed easily. As a result, the surface often becomes dirty or the transparency deteriorates.

An object of the present invention is to provide a polyolefin resin additive that does not bleed onto the surface of a polyolefin resin molded sheet, etc., increases its compatibility with the polyolefin resin, and provides extremely excellent transparency.

That is, the present invention is an additive for polyolefins in which terephthalic acid is attached and integrated on the surface of dibenzylidene sorbitol or its nuclear substituted product, and this additive is used in polyolefin resin (i).

Dibenzylidene sorbitol or its nuclear substituted product is added in such a proportion that substantially o, oi to 2 parts by weight are present based on the weight part.

The polyolefin resin whose transparency and bleeding phenomenon are improved by the present invention is an aliphatic monoolefin having 2 to 6 carbon atoms and has a number average molecular weight of about 10.000 to 200,00.
0, preferably about 30.0110 to 150,000 homopolymers or copolymers, such as polypropylene homopolymer, propylene-ethylene copolymer, linear polyethylene, low density polyethylene, medium density polyethylene,
High-density poly, ethylene, polymethylterpene, and mixtures of two or more thereof, preferably polypropylene monopolymer, propylene-ethylene copolymer, linear polyethylene, and low-density polyethylene.

Further, dibenzylidene sorbitol or its nuclear substituted product used in the present invention is a compound having the following general formula, examples thereof include dibenzylidene sorbitol, di(p-
Methyl) benzylidene sorbitol, di(p-ethyl)
Examples include benzylidene sorbitol and ci(p-I'ol)benzylidene sorbitol.

Next, the terephthalic acid used in the present invention is 000H-C5
It is a white powder with a melting point of 300'0 (7) and is insoluble or sparingly soluble in general solvents such as water and alcohol, but dimethylformamide, N-methyl-2
- A dicarboxylic acid that is soluble in aprotic polar solvents such as pyrrolidone, dimethylacetamide, and dimethylsulfoxide. The material used in the present invention must have a purity of at least 95% and be free from odor and color.

By the way, as mentioned above, the addition of dibenzylidene sorbitol and an organic carboxylic acid or its anhydride to a polyolefin resin is described in JP-A No. 51-40094 and was known before this application, and this method According to the method, the compatibility between the polyolefin resin and dibenzylidene sorbitol can be improved, but on the other hand, it has the disadvantage that it tends to cause a bleeding phenomenon, which is likely to cause trouble.

However, the present invention selects terephthal e, which is not described in the above publication, as an organic carboxylic acid, and instead of adding it to the polyolefin resin at the same time as all dibenzylidene sorbitol, terephthalic acid is added to dibenzylidene sorbitol in advance. By adhering to the surface and integrating it and then adding it to the polyolefin resin, all of the above-mentioned drawbacks can be eliminated. In other words, terephthalic acid has a very high melting point of 300°C, and the temperature at which it sublimes is also above the melting point, so it does not sublimate at all between 180°C and 280°C, which is the molding temperature of general polyolefin resins. Therefore, no bleeding occurs at all. However, when this terephthalic acid and dibenzylidene sorbitol are blended into a polyolefin resin, a complete mixing state cannot be achieved in the polyolefin resin due to the difference in specific gravity and melting point, and therefore, the intended objective of improving transparency is not achieved much. I can't wait. However, the present inventor created a fine suspension by dissolving terephthalic acid in a polar solvent and adding a large amount of water or alcohol, and added a small amount of an anion activator as an adhesive if necessary. It has been discovered that by adding dibenzylidene sorbitol or its nucleus-substituted wedge to it, a small amount of terephthal particles can be attached to the powder surface of dibenzylidene sorbitol or its nucleus-substituted wedge very effectively. When they added it, they discovered the effect mentioned above. In other words, aprotic polar solvents can be mixed with water and alcohol in any ratio, so when a polar solvent solution of terephthalic acid is diluted with water or alcohol, extremely fine microcrystals of terephthalic acid precipitate out, forming a good suspension. When a powder of dibenzylidene sorbitol or its nuclear substituted product is placed in this suspension and stirred, the microcrystals are adsorbed and attached to the powder surface. Ru. The mixing ratio of dibenzylidene sorbitol and terephthal is 95:1.
The ratio is 0 to 99.9:1, preferably 92:8 to 99:1, more preferably 93 to 97:3, and although it is not necessary to use an anionic surfactant, the use of an anionic surfactant can reduce p overspeed. is accelerated and adsorption is completed. The amount of anionic surfactant to be used is 0.01 to 0.05 parts, more preferably 1 to 0.3 parts, per 100 parts of dibenzylidene sorbitol.

Next, further explanation will be given by giving representative examples.

Example 1 Dibenzylidene sorbitol 97 parts (manufactured by Easy Kagaku ■) Terephthalic acid 3 parts (Kishida Chemical ■ reagent grade) N11 methyl-2-pyrrolidone 30 parts (manufactured by Mitsubishi Kasei ■) Anionic surfactant 0.2 parts (NOF ■Nissan Trucks H-45) Water 50
When 0 parts of terephthalic acid and 3 parts of N-methyl-2-pyrrolidone are mixed, heated to 5σ to 60'c and stirred, they are completely dissolved in about 10 minutes to form a clear solution. 2 parts of Nissantra and Cus H-450 were added to the mixture, stirred, and left to stand.

Prepare 500 parts of water in a separate container, and pour the above terephthalic acid solution into it while stirring. Beautiful blue-white emulsion (
suspension) is produced. Next, dibenzylidene sorbitol powder is added to this suspension and stirred until it becomes a uniform slurry. If you leave it for a while, the precipitated terephthalic acid adsorbed by dibenzylidene sorbitol will gradually settle out and the supernatant liquid will become transparent, so immediately transfer the entire amount from house to house by vacuum filtration using a filter press, centrifuge, or door paper. and rinse thoroughly with water. At this time, since terephthalic acid does not dissolve in water at all, the entire amount is adsorbed by dibenzylidene sorbitol and does not flow to the filtrate. The white cake separated from the water is pulverized, dried, and further pulverized to obtain a powdered additive in which terephthalic acid is adsorbed and integrated with dibenzylidene sorbitol.

In this case, a lower alcohol such as methanol, a mixture thereof, or a mixture of water and alcohol in any proportion can be used instead of water.

Example 2゜Dibenzylidene sorbitol 98 parts Terephthalic acid 2 parts N-methyl-2-pyrrolidone (9) parts Water 500 parts Terephthalic acid 2 parts and N-methyl-2-pyrrolidone were mixed in a water bath at 50"O. Stir to dissolve completely.

Pour 500 parts of water into another container and stir while pouring the above terephthalic acid solution to obtain a white emulsion. Add powdered dibenzylidene sorbitol into this and stir for about 30 minutes until it becomes uniform or creamy. After that, the Oki filter is washed with water using a centrifugal separator.

If the produced white cake is dried and pulverized, a powdered additive in which terephthalic acid is adsorbed and integrated with dibenzylidene sorbitol is obtained.

Example 3 Di(p-methyl)benzylidene sorbitol 95 parts Terephthalic acid 5 parts Dimethylformamide 30 parts Water 200 parts Methyl alcohol 300 parts Terephthalic acid 5 parts and dimethylformamide 30 parts were mixed and heated to 60°C to completely dissolve. dissolve.

A translucent white emulsion is obtained by placing 200 parts of water and 300 parts of alcohol in a separate container and pouring the terephthalic acid solution into the container while stirring.

In this, di(p-methyl)benzylidene sorbitol 9
By adding 5 parts of terephthalic acid to di(p-methyl)benzylidene sorbitol and stirring it for about 30 minutes until it becomes uniform or in the form of a cream, the additive was treated in exactly the same manner as in Example 2. can get.

Example 4 Di(p-ethyl)benzylidene sorbitol 97 parts Terephthalic acid 3 parts Dimethyl sulfoxide 40 parts Nissan Rapizole B-300, 1 part (anionic activator manufactured by NOF ■) Water 500 parts Treatment described in Example 1 By carrying out the same treatment as in the method, an additive in which terephthalic acid is adsorbed and integrated with di(p-ethyl)benzylidene sorbitol can be obtained.

Next, the additive all-polypropylene resin obtained in this way (
Showa Denko ■ Manufactured by random copolymer MGilO) 10
Add all the amounts listed in the table below to part 0 and make the thickness IX at a temperature of 240°C.
The results of molding a plate-like product and examining its transparency and bleeding are shown below. Test numbers 1 and 2 are cases where dibenzylidene sorbitol or hashi(p-methyl)benzylidene sorbitol and terephthalic acid were added to the polypropylene resin at the same time.

(Amount) (Test results)

Claims (1)

[Claims] 1. An additive for polyolefin resins in which terephthalic acid is attached and integrated on the powder surface of dibenzylidene sorbitol or its nuclear substituted product.