JPH069643A - Method for storing dibenzylidene sorbitols - Google Patents

Abstract

PURPOSE:To suppress increase in a benzaldehyde with time by preserving a dibenzylidene sorbitol at a specific temperature. CONSTITUTION:A dibenzylidene sorbitol of the formula (R and R' are H, halogen, 1-8C alkyl or 1-8C alkoxy; n and m are 1-3) at <=30 deg.C. 1,2,3,4-Dibenzylidene sorbitol may be cited as the compound of the formula. The compound of the formula can improve transparency of a resin by adding a small amount of the compound to a polyolefin resin, especially polyethylene, polypropylene or a copolymer consisting essentially of the polymer and is useful as an additive for resins in the field of molding various kinds of containers requiring transparency. Molded articles obtained by injection molding or extrusion molding of a polyolefin resin provided with transparency and using the compound of the formula has an extremely slight smell. The compound is also useful as a gelatinizing agent for various organic solvents.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a stable storage method for dibenzylidene sorbitols. More specifically, the present invention relates to a method for storing dibenzylidene sorbitols that suppresses an increase in benzaldehydes over time.

[0002]

2. Description of the Related Art Dibenzylidene sorbitols have the effect of improving the transparency of a polyolefin resin, especially polyethylene, polypropylene or a copolymer containing them as a main component, in a small amount to improve the transparency of the resin. It is a compound useful as an additive for resins in the field of molding of various containers and the like, which require high properties. It is also a compound useful as a gelling agent for various organic solvents.

However, dibenzylidene sorbitols are relatively poor in stability, and may release benzaldehydes during storage or processing to give off a bad odor, and may give an aldehyde odor or coloring to a molded article, which is large depending on the use. It became an obstacle and hindered the growth of demand. Further, even when refined to such an extent that the odor cannot be detected substantially, the dibenzylidene sorbitols are decomposed by the action of temperature and moisture during storage, which causes the odor.

Conventionally, the following methods have been studied and disclosed for solving the above-mentioned problems. JP-A-53-5165 or JP-A-57-185287 discloses a method of mixing dibenzylidene sorbitols with a lower aliphatic alcohol or a lower aliphatic ketone under heat, and Japanese Patent Application Laid-Open No. 60-58.
-32791 or JP-A-60-42385 describes a method of treating with hydroxylamine or phenylhydrazines. However, all of these methods are methods for removing benzaldehydes contained as impurities, and do not improve the stability against decomposition during storage or the stability due to storage methods.

Japanese Unexamined Patent Publication (Kokai) No. 62-4289 discloses a sorbitol derivative composition having improved thermal stability, which is obtained by adding a non-aromatic organic amine to a sorbitol derivative. However, in the field where these compositions are used as additives for resins and used in food containers and the like, there is concern about the safety of amines.

JP-A-57-21440 and JP-A-1-126352 disclose compositions in which the surface of a solid powder of dibenzylidene sorbitol or a di-substituted benzylidene sorbitol derivative is coated with a saturated higher fatty acid such as behenic acid. Has been done. In this case, it is described that the effect is small if it is simply added, and it is necessary to coat the surface with a surfactant or the like. Therefore, the manufacturing process becomes complicated, and it is necessary to use a relatively large amount of 5 to 50 parts by weight of higher fatty acid to 95 to 50 parts by weight of dibenzylidene sorbitols.

In addition, a method in which a carboxylic acid metal salt such as calcium stearate is blended in an amount of about 0.1 part by weight with respect to 100 parts by weight of the resin is generally adopted at the time of processing the polyolefin resin. Therefore, it is not possible to improve the odor of molded articles when dibenzylidene sorbitols are added.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for storing dibenzylidene sorbitol capable of significantly suppressing an increase in dibenzylidene sorbitols during storage.

[0009]

The present inventors have found that the aldehyde odor and coloration of molded articles are correlated with the amount of benzaldehydes contained in dibenzylidene sorbitols before being used for processing. As a result, the inventors conducted extensive studies on the method for removing benzaldehyde contained in dibenzylidene sorbitols and the method for inhibiting increase during storage. As a result, they have found that by storing dibenzylidene sorbitols at a temperature of 30 ° C. or lower, it is possible to prevent an increase in benzaldehydes, and have completed the present invention. That is, the present invention provides the following general formula (1)

[0010]

[Chemical 2]

[In the formula, R and R ′ each independently represent an atom or a group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, and an alkoxy group having 1 to 8 carbon atoms. And n and m represent an integer of 1 to 3. ] The dibenzylidene sorbitols represented by
0 ° C. or lower, preferably 20 ° C. or lower, more preferably 10
It provides a method of storing at a temperature of ℃ or below.

The dibenzylidene sorbitols of the general formulas (1) and (2) used in the method of the present invention include 1,3
-2,4-dibenzylidene sorbitol, 1,3-2
4-di (p-methylbenzylidene) sorbitol, 1,
3-2,4-di (p-ethylbenzylidene) sorbitol, 1,3-2,4-di (p-chlorobenzylidene) sorbitol, 1,3-2,4-bis (dimethylbenzylidene) sorbitol and the like. Compounds having a benzylidene group, 1,3-benzylidene-2,4-p-methylbenzylidenesorbitol, 1,3-benzylidene-
2,4-p-ethylbenzylidene sorbitol, 1,3
-Benzylidene-2,4-p-chlorobenzylidene sorbitol, 1,3-p-methylbenzylidene-2,4-
Benzylidene sorbitol, 1,3-p-methyl benzylidene-2,4-p-chlorobenzylidene sorbitol, 1,3-p-methyl benzylidene-2,4-p-ethyl benzylidene sorbitol, 1,3-p-ethyl benzylidene- 2,4-benzylidene sorbitol, 1,
Examples thereof include compounds having different benzylidene groups such as 3-p-ethylbenzylidene-2,4-p-methylbenzylidenesorbitol and 1,3-p-ethylbenzylidene-2,4-p-chlorobenzylidenesorbitol.

When the dibenzylidene sorbitol according to the above-mentioned storage method of the present invention is used as an additive for resins such as polyolefins even after being stored for a long period of time, it is possible to impart transparency to the molded product and to obtain a product with extremely low odor .

Examples of the polyolefin resin to which the compound according to the present invention is used as an additive include polypropylene, low density polyethylene, high density polyethylene, ethylene-propylene copolymer and the like.

[0015]

INDUSTRIAL APPLICABILITY The storage method of the present invention can remarkably suppress the change with time during storage as compared with the prior art, and, surprisingly, suppress the change with time in this way, and the benzaldehyde content is at a low level. It was also found that the molded product obtained by injection or extrusion molding of the transparency-provided polyolefin resin obtained by using the dibenzylidene sorbitols of (1) has extremely low odor.

[0016]

EXAMPLES The present invention will be described in more detail below with reference to examples. Examples 1 to 4 and Comparative Examples 1 to 2 1,3-2,4-dibenzylidene sorbitol was stored at the temperature and humidity shown in Table 1, and the content of benzaldehyde was analyzed by liquid chromatography over time. The results are shown in Table 1.

[0017]

[Table 1]

Examples 5 to 9 and Comparative Examples 3 to 5 1,3-2,4-di (p-ethylbenzylidene) sorbitol was stored at the temperature and humidity shown in Table 2, and the content of benzaldehyde was changed with time. It was analyzed by liquid chromatography. The results are shown in Table 2.

[0019]

[Table 2]

Claims (3)

[Claims] 1. The following general formula (1) (chemical formula 1): [In the formula, R and R ′ are each independently a hydrogen atom,
Halogen atom, C1-C8 alkyl group, C1-C1
Represents an atom or a group selected from the group consisting of 8 alkoxy groups, and n and m each represent an integer of 1 to 3. ] The method for storing dibenzylidene sorbitols represented by the above formula, wherein the storage temperature is 30 ° C. or lower. 2. The dibenzylidene sorbitols are 1,3
-2,4-dibenzylidene sorbitol, 1,3-2
4-di (p-methylbenzylidene) sorbitol, 1,
From the group consisting of 3-2,4-di (p-ethylbenzylidene) sorbitol, 1,3-2,4-di (p-chlorobenzylidene) sorbitol, 1,3-2,4-bis (dimethylbenzylidene) sorbitol The method for storing dibenzylidene sorbitols according to claim 1, which is selected. 3. The dibenzylidene sorbitols are 1,3.
-Benzylidene-2,4-p-methylbenzylidene sorbitol, 1,3-benzylidene-2,4-p-ethylbenzylidene sorbitol, 1,3-benzylidene-
2,4-p-chlorobenzylidene sorbitol, 1,3
-P-methylbenzylidene-2,4-benzylidene sorbitol, 1,3-p-methylbenzylidene-2,4-
p-chlorobenzylidene sorbitol, 1,3-p-methyl benzylidene-2,4-p-ethyl benzylidene sorbitol, 1,3-p-ethyl benzylidene-2,4
-Benzylidene sorbitol, 1,3-p-ethylbenzylidene-2,4-p-methylbenzylidene sorbitol, 1,3-p-ethylbenzylidene-2,4-p-chlorobenzylidene sorbitol The method for storing dibenzylidene sorbitols according to claim 1.