JPH07149766A - Fibrous diacetal compound and its production - Google Patents

Abstract

PURPOSE:To obtain the compound useful as a fluidity improver of normal temperature dispersion type and an excellent dispersible nucleating agent for crystalline polymer, having excellent workability by heating a crystalline powdery diacetal compound to change a crystal state. CONSTITUTION:This compound of the formula (R<1> and R<2> are each H ora 1-4C alkyl; (m) and (n) are each 1-5; (p) is 0 or 1) having a fibrous crystal state and 2,000A to 10mu diameter of section is obtained by heating a crystalline powdery diacetal compound to 120-250 deg.C to change a crystal state. A supercooled material of the molten diacetal compound is preferably maintained at 120-250 deg.C and crystallized.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a diacetal compound having a fibrous crystal form and a method for producing the same.

[0002]

2. Description of the Related Art 1,3: 2,4-dibenzylidene sorbitol (hereinafter abbreviated as "DBS") and its aromatic ring are alkyl groups such as methyl group, ethyl group, isopropyl group and dimethyl group. The substituted diacetal compound is
Polyester molding (JP-A-50-151250), paint (JP-A-49-23229), ink (JP-A-51)
No. 59506), an adhesive (JP-A-48-44332).
It is well known that it is useful as a gelling agent, a thixotropic agent or a thickening agent, and a polyolefin crystal nucleating agent in a wide range of fields (JP-A-50).
-124034, JP-A-50-139150, JP-A-50-134034, JP-A-51-59506, etc.).

Generally, when a thixotropic agent, a thickener or the like is applied as an additive for polyester molding, paints, inks, adhesives, etc., it can be applied by dispersing at room temperature without specific steps such as heating and cooling. Is desirable.

However, since all of the conventionally known diacetal compounds are powdery crystalline substances, the room temperature dispersion method cannot be applied. To apply these diacetal compounds to the above fields, a solvent is used. , A step of heating the entire system to dissolve the diacetal compound and then cooling to form a gel, and a step of further sufficiently kneading as necessary.

As a solution to this problem, the present inventor has previously proposed the production of an amorofus sponge-like xerogel of DBS, which is formed by freeze-drying a DBS / organic solvent system gel ( Japanese Patent Laid-Open No. 63-1207
88).

The DBSs obtained by this method are amorophous in that the X-ray pattern of the fibrils formed in the matrix is significantly different from that of the crystals of the original DBSs, and the electron micrographs show that Obviously, it has a feature that it is composed of extremely small fibrils having a cross-sectional diameter of about 100 Å (the latest technology of polymer additives, p204, CM).
C Publishing, 1988).

The above-mentioned DBSs have a characteristic of being a room temperature dispersion type, but have a difficulty in industrialization in that they adopt a freeze-drying method, which is difficult to manufacture continuously. Further, since the bulk specific gravity of the freeze-dried product is extremely small, there is a problem in handling it.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel and useful crystalline diacetal compound which is excellent in workability and can be applied to a room temperature dispersion method in each conventionally known field, and a method for producing the same. .

[0009]

Means for Solving the Problems As a result of earnest studies to achieve the above object, the present inventor has found that: By heating a conventionally known crystalline powdered DBS under a specific temperature condition, a crystalline morphology transition from a crystalline powdery state to a fibrous crystal occurs without going through a gel formation state, and The density of the DBS is not so different from that of the original crystalline powder, and the DBSs having a morphology not described in the literature, that is, a crystallinity different from the amorophous fibrils and having a relatively large cross-sectional diameter, are formed. Find out the facts to be gained, 2. Further, they have found that the same crystalline fibrous morphology diacetal as described above can be prepared by maintaining the supercooled product of the molten diacetal compound at a specific temperature. It was found that the thus obtained fibrous DBSs are extremely useful as a room temperature dispersion type thixotropic agent and the like, and as a polymer crystal nucleating agent having a good dispersibility. The present invention has been completed based on such findings.

The diacetyl compound according to the present invention is represented by the general formula (I), has a fibrous crystal form, and has a cross-sectional diameter of 2000 angstroms to 10 microns, preferably 4000 angstroms or more. Characterize.

[In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and m and n are 1 to 1;
Indicates an integer of 5. p represents 0 or 1. ]

Specific examples of the diacetal compound represented by formula (I) include DBS, methyl group, ethyl group,
Examples thereof include DBS in which each aromatic ring is substituted with 1 to 5 alkyl groups having 1 to 4 carbon atoms such as isopropyl group, and similar xylitol derivatives. At this time, the position of each substituent does not matter. Further, the so-called symmetric type in which the substituents on the two aromatic rings are exactly the same or the so-called asymmetric type in which the substituents are different from each other may be used.

The fibrous diacetal compound is prepared by a known synthesis method (for example, JP-B-48-43748, JP-A-5-48748).
6-108791, JP-A-56-161391, JP-A-1-149789, JP-A-2-231488).
The diacetate compound powder obtained by the above method, preferably 120 to 120% by weight of a dry powder having a volatile component of about 0 to 20% by weight.
It can be easily obtained by heating at 250 ° C., preferably about 130 to 200 ° C. to cause the crystal form transition from powdery crystals to fibrous crystals.

The rate of crystal form transition from powder crystals to fibrous crystals increases as the heating temperature increases. For example, the morphological transition is completed by performing heat treatment at 140 to 200 ° C. for about 15 to 60 minutes.

In this heat treatment method for fine powder crystals, 1
If the temperature is lower than 20 ° C, the transition rate is low and the transition is not substantially generated, which is not practical, and if the temperature exceeds 250 ° C, the diacetal compound is decomposed or colored, which is not preferable.

Another method is a high-temperature treatment method for the melt. This method is accomplished by keeping the supercooled product of the molten diacetal compound at a high temperature of 120 to 250 ° C. When it is rapidly cooled to 100 ° C. or lower, it becomes a spherulite form and a crystalline fiber form cannot be obtained.
Further, generally, at a temperature above 250 ° C., the growth rate of the fibrous crystals is small, and decomposition of the diacetal compound is caused, which is not practical.

The heat treatment which causes the morphological transition between crystals due to heating or the morphological change from the molten supercooled product to the formation of fibrous crystals is carried out in a state where the crystal powder or the molten material is allowed to stand, or in an appropriately mixed state. You can

The atmosphere in the heat treatment step can be carried out without any particular limitation. That is, it may be normal pressure, reduced pressure, or increased pressure, and may be in the presence of air, in an inert gas such as nitrogen, carbon dioxide, or argon, or in a solvent gas atmosphere such as steam, methanol, or hydrocarbon. Generally, a nitrogen gas atmosphere under reduced pressure is desirable.

The fibrous diacetal compound thus obtained has a larger specific surface area per unit weight than the conventionally known diacetal compound, but its bulk specific gravity does not change much (about 0.3), and the freeze-dried product is lyophilized. The bulk density of the products is extremely small (about 0.01) and the drawbacks of being difficult to handle have been resolved, and the fields in which diacetal compounds have been used so far, such as polyester molding, paints, inks, adhesives, etc. It is useful as a room temperature dispersion type gelling agent, thixotrope agent or thickening agent in the field, and is also applied as a polyolefin crystal nucleating agent having good dispersibility.

The present invention will be described in detail below with reference to examples. Example 1 45 g of DBS crystal powder (trade name "Gel-ol D", manufactured by Shin Nippon Rika Co., Ltd.) was placed in a 10 × 20 × 4 cm stainless steel vat, and this was placed in a thermostatic chamber set at 130 ° C.
Let stand for a minute. As a result of an observation under an optical microscope (a polarizing microscope manufactured by JASCO Corporation, the same applies hereinafter) under Krusnikol, it was confirmed that the crystal morphology was transformed into a fibrous shape as shown in the micrograph shown in FIG.

Application Example 1 2 g of DBS of the fibrous crystals obtained in Example 1 was added to 100 g of styrene monomer at room temperature, homogenized and mixed for 10 minutes, and allowed to stand for 1 day to give a gel without fluidity.

Application Comparative Example 1 When a gel ol D crystal powder was applied to styrene monomer by the same method as in Application Example 1, there was almost no change in fluidity and no gel formation was observed.

Example 2 45 g of 1,3: 2,4-bis (p-methylbenzylidene) sorbitol crystal powder (trade name "Gel-or MD", manufactured by Shin Nippon Rika Co., Ltd.) was added to 10 x 20 x 4 cm stainless steel. It was placed in a vat and left standing in a nitrogen atmosphere thermostatic chamber set at 190 ° C. for 10 minutes. As a result of the optical microscope observation under the Krusnikol, it was confirmed that the crystal morphology was transformed into a fibrous shape as shown in the micrograph shown in FIG.

Application Example 2 2 g of the methyl-substituted DBS of the fibrous crystals obtained in Example 2 was added to 100 g of styrene monomer at room temperature, homogenized and mixed for 10 minutes, and allowed to stand for 1 day to give a gel without fluidity. It was

Application Comparative Example 2 When a gel ol MD crystal powder was applied to styrene monomer in the same manner as in Application Example 2, there was almost no change in the fluidity and no gel formation was observed.

Example 3 In a nitrogen atmosphere, 10 g of gelol MD crystal powder was placed in a 10 × 20 × 4 cm stainless steel bat at 270 ° C.,
This was a melt of Gelall MD. Next, the vat was moved to a temperature-controlled room under a nitrogen atmosphere at 200 ° C., held for 20 minutes, and then returned to room temperature. As a result of an optical microscope observation under Cusco Nicol, it was confirmed that a fibrous crystal morphology was generated as shown in the micrograph of FIG.

[0026]

INDUSTRIAL APPLICABILITY The fibrous crystal diacetal compound obtained by the method according to the present invention is excellent in workability and is used in various fields as a room temperature dispersion type fluidity modifier and a good dispersive nucleating agent for crystalline polymers. Can be widely applied in.

[Brief description of drawings]

FIG. 1 is an optical micrograph of a fibrous crystal DBS obtained in Example 1 under Cruz Nicol.

FIG. 2 is a methyl-substituted D of the fibrous crystal obtained in Example 2.
It is an optical microscope photograph under BS Cruz Nicol.

FIG. 3 is a methyl-substituted D of the fibrous crystal obtained in Example 3.
It is an optical microscope photograph under BS Cruz Nicol.

[Procedure amendment]

[Submission date] November 21, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

Claims (3)

[Claims] 1. A compound represented by the general formula (I), having a fibrous crystal morphology, and having a cross-sectional diameter of 2000 angstroms to 1.
A diacetal compound characterized by being 0 micron. [Chemical 1] [In formula, R < ¹ >, R < ² > is the same or different and shows a hydrogen atom and a C1-C4 alkyl group, and m and n show the integer of 1-5. p represents 0 or 1. ] 2. A diacetal compound in the form of crystalline powder is used.
The method for producing a diacetal compound according to claim 1, wherein the crystal form is transformed by heating at 0 to 250 ° C. 3. A supercooled product of a molten diacetal compound is
The method for producing a diacetal compound according to claim 1, characterized in that it is held at 20 to 250 ° C. for crystallization.