JPH0717648B2 - Stabilized dibenzylidene sorbitol compositions - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stabilized dibenzylidene sorbitol composition.

[Prior Art] Dibenzylidene sorbitols (hereinafter abbreviated as "DBSs") are widely used as modifiers of crystalline polyolefin resins, effective for improving rigidity and shortening molding cycle, and It has epoch-making properties such as improved transparency (polymer processing, Volume 35, No. 1,
30-35 (1986)).

However, conventional DBSs tended to lack thermal stability. Therefore, by a usual processing method, for example, when a resin composition obtained by blending DBSs as a nucleating agent in a polyolefin-based resin is heat-molded, DBS is subjected to heat-molding.
It has been pointed out that problems such as the decomposition of odors and the generation of odor, and the molded products being colored. Further, such a problem has been a major obstacle to the working environment at the time of molding processing and the use of odorless products such as food packaging.

As a countermeasure, for example, a heat stabilizer such as an aliphatic carboxylic acid metal salt may be blended in the resin in advance or at the same time (JP-A-58-104933 and JP-A-62-53360). Method of coating the surface in layers (Japanese Patent Laid-Open No. 62-50355)
JP-A-62-138545), a method of adding a non-aromatic organic amine (JP-A-62-4289), and the like. As a result of the study by the present inventors, although some improvement was recognized by these methods, it was difficult to sufficiently suppress the decomposition of DBS by merely applying a heat stabilizer to the resin.

In addition, in a field of application, such as food packaging, where sufficient hygiene must be taken into consideration, it is desirable that the additive amount of a safe additive be as small as possible.

On the other hand, when a mono-substituted product or a tri-substituted product is mixed with dibenzylidene sorbitol, the finding that the modifying effect of the polyolefin resin is decreased, and as a method for solving such a problem, the above-mentioned substituted product is washed with an aliphatic lower alcohol. A method for removing and purifying dibenzylidene sorbitol has been proposed (JP-A-53-5165). However,
Even with such a purified product, the thermal stability was still insufficient.

In the following detailed examination, the following two important facts were revealed. That is, (1) although strongly acidic compounds such as sulfuric acid, phosphoric acid, and p-toluenesulfonic acid, which were applied as catalysts when producing DBSs, were almost neutralized and removed in the usual production process,
Since the product is a powder, a trace amount that is not a problem usually remains, and this cannot be completely removed by simple solvent refining. This strongly acidic compound locally promotes the hydrolysis of DBS under high temperature heating conditions even if the amount remaining in the product is very small, and as a result of generating aromatic aldehydes in the ppm order, the acidic substance Presence is the cause of the generation of odors.

(2) The melting points of DBSs themselves are high and very stable. For example, 220 ° C. for 1,3: 2,4-dibenzylidene sorbitol, 260 ° C. for 1,3: 2,4-bis (methylbenzylidene sorbitol), and the benzaldehydes used as raw materials are benzaldehyde and cumyl aldehyde. 138 ° C for untargeted DBSs consisting of mixtures. On the other hand, conventional products contain a small amount of positional isomers such as 5-membered ring acetal compounds such as 1,2: 3,4-dibenzal compound or 1,2: 3,4: 5,6-tribenzal compound. However, in most cases, this is amorphous and its melting point is as low as 80 ° C. or lower, which reduces the thermal stability of DBSs as products.

[Problems to be Solved by the Invention] The present inventors suppress the thermal decomposition of DBSs that occur during heat molding of resin by applying a relatively small amount of a stabilizer, improve the working environment, and improve hygiene. As a result of diligent studies to develop DBSs with good thermal stability that can prepare molded products with no problems in terms of purification, purification of DBSs obtained by washing away impurities such as positional isomers with a specific solvent It is possible to achieve the intended purpose by completely neutralizing the strongly acidic substance mixed in the substance and eliminating it by neutralizing it, and then further compounding a specific substance as a heat stabilizer. The present invention has been completed, and the present invention has been completed based on this finding.

That is, an object of the present invention is to provide a DBS composition having excellent thermal stability.

[Means for Solving the Problems] The stabilized DBS composition according to the present invention has a dibenzylidene sorbitol represented by the general formula (I) in which the positional isomer is reduced to 0.2% by weight or less. It is characterized in that an alkali metal compound and an alkaline organic amine compound are blended with the purified product of the above-mentioned dibenzylidene sorbitol.

[Wherein X and X'are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a halogen atom. m and n are the same or different and are 1 to
Represents an integer of 5. p represents 0 or 1. The purified product of DBS according to the present invention means a compound represented by the following general formula (I), which is a condensation product of an aromatic aldehyde and a polyhydric alcohol having a valence of 5 or more, washed with a specific solvent. The mono- or tri-substituted product and usually 1.
It is a purified product obtained by removing the regioisomer contained in about 0 to 2.5% by weight.

Here, as the aromatic aldehydes, benzaldehyde, a benzaldehyde substituted product having 1 to 5 alkyl groups having 1 to 3 carbon atoms, a benzaldehyde substituted product having 1 to 5 halogen atoms substituted, and 1 to 3 carbon atoms Examples thereof include benzaldehyde substitution products in which 1 to 5 alkoxy groups are substituted, and a mixture thereof in any ratio.

Examples of the polyhydric alcohol include sugar alcohols such as sorbit and xylit, and a mixture thereof in any ratio.

The compounds obtained include not only asymmetric types having different types and numbers of aromatic substituents or the same symmetrical types and mixtures thereof, but also arbitrary mixtures of sorbit derivatives and xylit derivatives.

Solvents suitable as cleaning solvents include (1) relatively high volatility and good dryability, (2) no gelation even after cooling after heat treatment, (3) good dispersion of DBSs (4) It is a good solvent for isomers, and the like, as long as it can satisfy various conditions such as (A) an aliphatic lower alcohol such as methanol, ethanol or isopropanol, n- 6 carbon atoms such as hexane
To 12 saturated hydrocarbons, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as toluene, or one or more solvents selected from them, and (B)
Examples thereof include a mixed solvent of one or more selected from the group consisting of ketones exemplified by acetone, methyl ethyl ketone, methyl isobutyl ketone and the like.

In this case, the presence of water in the system within a range that does not impair the cleaning effect is no problem and is more realistic.

As a specific purification treatment method, the crude product of DBS is 4 to 20
Disperse in about twice (weight) amount, preferably 6 to 15 times (weight) solvent, at room temperature to heating conditions, preferably 40 to 80
After holding at about C for about 1 minute to 3 hours, preferably for about 1 hour or less, the mixture is cooled to near room temperature and then filtered to reduce the amount of positional isomers mixed in the purified product to 0.2% by weight or less.

As a matter of course, this method can also be applied as a flow-through purification method.

However, even if such a purification treatment is performed, the strongly acidic substance applied as the acid catalyst cannot be completely removed,
In the purified product, a strong acidic substance of about 10 to 100 ppm usually remains. This development is peculiar to the compound and is presumed to occur due to its strong liquid adsorption property, but the cause has not been completely clarified.

In the present invention, as the alkali metal compound applied to neutralize the strongly acidic substance, sodium hydroxide, inorganic alkali such as potassium hydroxide and citric acid, abietic acid, lactic acid, lactic acid dimer stearate, succinic acid , Benzoic acid and its nuclear substitution product, stearic acid, isostearic acid, hydroxystearic acid, dihydroxystearic acid, tetrahydroxystearic acid, dimer acid, oleic acid, fatty acids exemplified by behenic acid, ethylenediaminetetraacetic acid (hereinafter, " EDTA ") and inorganic weak acids such as boric acid, and alkali metal salts such as lithium, sodium and potassium.

The addition amount of the above-mentioned alkali metal compound is preferably an amount sufficient to completely neutralize the remaining strong acidic compound, and unlike ordinary neutralization, it is added in an amount of 10 to 20 times the equivalent amount of the acidic compound. .

In the neutralization treatment according to the present invention, it is desirable to stir and mix the DBSs in the solvent under the conditions of the temperature mentioned above, and the strongly acidic substance localized by such treatment is localized. Is substantially neutralized, and the local hydrolysis-promoting action of this substance can be eliminated.

As the alkaline organic amine compound applied as a heat stabilizer in the present invention, a compound having a melting point lower than that of DBSs is preferable because it exhibits an alkali stabilizing effect during heating, specifically, N, N- Diethanol alkyl (C12-24 which may have a hydroxyl group) amine, N, N-dipropanolalkyl (C12-24 which may have a hydroxyl group) amine, N, N-polyethoxy (degree of polymerization = 1 20) Alkyl (C12 ~
24) amine, N, N-polypropoxy (degree of polymerization = 1-20) alkyl (C12
24) In addition to aliphatic amines such as amines, bis (2,2,6,6-
Tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) butanetetracarboxylate , Tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) butanetetracarboxylate, poly [[6- (1,1,3,3-tetramethylbutyl) imino-1,3,5- Triazine-2,4-diyl] [2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl (imino)], amber Acid dimethyl-1 (2-hydroxyethyl) -4-
Hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, dimethyl-2- (4-hydroxy-2,2,6,6-
Tetramethylpiperidine) ethanol polycondensate, 2 (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-
Memethylphenyl) benzotriazole, "Sanol LS-770", "Sanol LS262" manufactured by Sankyo Co., Ltd.
Examples thereof include hindered amine compounds such as 6 ”and“ HA-70G ”.

The above-mentioned alkaline organic amine compound is not limited to the following, but is usually added in an amount of about 10 ppm to 10% by weight, more preferably 100 ppm to 6% by weight, based on DBS.
If it is less than 10 ppm, it is difficult to obtain a predetermined effect, and if it is more than 10% by weight, no significant difference in response is observed and it causes coloring during heating in the reaction, which is not preferable.

If desired, the DBSs according to the present invention may further contain a radical inhibitor in an amount of about 100 to 5,000 ppm.

Specific examples of the applied radical inhibitor include bisphenol A, butylhydroxyanisole (hereinafter abbreviated as "BHA"), 2,6-di-tert-butylhydroxytoluene (hereinafter "BHA").
Abbreviated as "HT". ), 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-phenol, 4,4′-methylenebis (2,6-di-tert-butylphenol), 2, 6-di-tert-butyl-α-dimethylamino-p-cresol, 2,6-di-tert-butyl-p-ethylphenol, 2,4,6-tri-tert-butylphenol, tris (3,5- Di-tert-butyl-4-hydroxybenzyl) isocyanurate, tris [β- (3,5-tert-butyl-4-hydroxyphenyl) propionyl-oxyethyl] isocyanurate, 1,3,5-trimethyl-2,4 , 6-tris (3,5-di-tert-
Butyl-4-hydroxybenzyl) benzene, 1,6-hexanediol-bis [3- (3,5-di-tert-
Butyl-4-hydroxyphenyl) propionate], 6- (4-hydroxy-3,5-di-tert-butylanilino) -2,4-bisoctyl-thio-1,3,5-triazine, tetrakis [methylene-3-] (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane (hereinafter referred to as “Irganox 1010”, manufactured by Ciba Geigy, trade name), n-octadecyl-3- (3,5- Di-tert-butyl-4
-Hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-tert-butyl-
4-hydroxy-hydrocinnamamide, 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate diethyl ester, 2,2-thio-diethylenebis [3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate] and other phenolic compounds such as polymeric hindered phenols, tris (nonylphenyl) phosphite, tris (2,5-di-tert-butylphenyl) phosphite, tris (2 Phosphorus compounds such as 4,4-di-tert-butylphenyl) phosphite are exemplified.

The above-mentioned alkali metal compound, alkaline organic amine compound and radical inhibitor are used alone or in admixture of two or more.

The DBS according to the present invention is, for the purified product containing a predetermined amount of an alkali metal compound, added and mixed with an alkaline organic amine compound dissolved or dispersed in the same solvent as the cleaning solvent, and then the solvent is evaporated. It is manufactured by removing. However, the method is not limited to the above method as long as a predetermined effect can be obtained.

The DBS composition according to the present invention is useful as a nucleating agent applied to polyolefin resins and the like. Here, the polyolefin-based resin includes high-density polyethylene, medium-density polyethylene, low-density polyethylene including linear polyethylene, a copolymer having a polyethylene content of 50% or more, homopolypropylene, random polypropylene, block polypropylene, and polypropylene. An example is a copolymer having an amount of 50% or more.

In molding, generally used molding processing methods can be widely applied, and if necessary, conventionally known additives such as pigments, fillers, antistatic agents, foaming agents, lubricants, plasticizers and cross-linking agents are appropriately mixed. be able to.

Furthermore, it functions not only as a gelling agent, but also as a viscosity modifier, a thixotropic agent, an anti-sagging agent, an oil-water separating agent, a coagulant, an adhesive, a paint, a resin modifying agent, an aromatic agent, a water treatment agent, Solidification / collection of spilled oil, fragrance, cosmetics, civil engineering, building materials, lubricants, rust preventives, agricultural chemicals, pharmaceuticals, non-medical products, fuels, inks,
The same applies in areas where conventional products have been used, such as glue.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 10 g (30 pp) of crude product of [A] 1,3: 2,4-bis (methylbenzylidene) sorbitol (hereinafter abbreviated as “Me-DBS”)
m acid catalyst is included in cyclohexane / acetone (8/2:
Dispersed in 150 ml of mixed solvent, added 800 ppm of sodium stearate as an alkali metal compound, stirred for 1 hour under reflux conditions, cooled to room temperature, filtered and purified Me-DBS Got Based on the purified product, N, N-diethanol tallow alkylamine 1% and 1
150 ml of a solution prepared by previously dissolving 50 ppm of "Irganox 1010" in the solvent was added, stirred and heated to evaporate and remove the solvent. The amount of each additive compounded under each of the above conditions is based on Me-DBS.

When this product was heated in an oil bath at 260 ° C. for 5 minutes in a nitrogen atmosphere, the amount of aldehyde generated was 10 ppm when analyzed by GLC after extraction with acetone. Also, n
-The residual amount of isomers measured by the hexane extraction method is 0.
It was 05% by weight.

[B] 0.2 parts by weight of the above treated product, 0.1 parts by weight of calcium stearate and 100 parts by weight of polypropylene resin, and
Add 0.1 parts by weight of BHT and use a twin-screw lab plastomill.
Sheets having a thickness of 0.5 mm were continuously prepared by air-cooling over 30 minutes by melt mixing at 230 ° C. and continuously extruding. At this time, the odor resulting from the decomposition of aldehyde is
It was significantly suppressed as compared with the case of applying Me-DBS prepared as the same except that sodium stearate was not mixed in [A].

Example 2 Cyclohexane / acetone (5/5) as a purification solvent,
500 ppm potassium benzoate as an alkali metal compound,
Bis (1,2,2,6,6− as alkaline organic amine compound
5,000 ppm pentamethyl-4-piperidyl) sebacate
A stabilized Me-DBS was prepared in the same manner as in Example 1 except that BHA and 200 ppm were used. The amount of aldehyde generated is 1
It was 5 ppm and the amount of isomers was 0.06%.

Example 3 Toluene / ethanol (7/3) as a purification solvent, lithium behenate as an alkali metal compound at 500 ppm, and
300ppm EDTA, N, N as alkaline organic amine compound
-800 ppm dipropanol stearylamine and 4 BHT
Stabilized Me-DBS was prepared according to Example 1 except that 00 ppm was used. The generated aldehyde amount was 10 ppm and the isomer amount was 0.1%.

Example 4 Except that methanol was used as a purification solvent, potassium hydroxide was 100 ppm as an alkali metal compound, and N, N-polyethoxy (degree of polymerization = 15) -12-hydroxystearylamine was 5 wt% as an alkaline organic amine compound. Stabilized Me-DBS was prepared according to Example 1. The generated aldehyde amount was 10 ppm and the isomer amount was 0.05%.

Example 5 To a crude product of 1,3: 2,4-dibenzylidene sorbitol (hereinafter abbreviated as “DBS”), cyclohexane / acetone (7/3) was used as a purification solvent, and 600 ppm of potassium hydroxide was used as an alkali metal compound. As bis (2,2,6,6-tetramethyl-4-piperidyl) as an alkaline organic amine compound
Stabilized DBS was prepared according to Example 1 except that sebacate was used at 5,000 ppm. The amount of aldehyde generated is 1
It was 2 ppm and the amount of isomers was 0.13%.

Example 6 1,3-Dimethylbenzylidene-2,4-benzylidenesorbitol crude product was purified with methanol / water (9 /
1) as an alkali metal compound, potassium hydroxide 500pp
m as an alkaline organic amine compound, "Sanol S
Stabilized DBSs were prepared according to Example 1 except that 5% by weight of "-770" was used. The amount of aldehyde generated is 5
ppm and the amount of isomers was 0.08%.

Example 7 To a crude product of 1,3: 2,4-bis (ethylbenzylidene) sorbitol was added methanol / water (9/1) as a purification solvent,
1,000 ppm potassium oleate as an alkali metal compound
In the same manner as in Example 1, except that 8% by weight of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole was used as the alkaline organic amine compound.
Was prepared. The amount of generated aldehyde was 7 ppm and the amount of isomer was 0.05%.

Example 8 To a crude product of 1,3: 2,4-bis (chlorobenzylidene) sorbitol, n-hexane / methyl ethyl ketone (6/4) was used as a refining solvent, and potassium stearate (1,000 ppm) was used as an alkali metal compound. Stabilized DBSs were prepared according to Example 1 except that 200 ppm of "Sanol LS2626" was used as the amine compound. The amount of generated aldehyde was 7 ppm and the amount of isomer was 0.05%.

Example 8 Methanol / water (9/1) as a purification solvent for crude DBS
As the alkali metal compound, lithium benzoate 1,000p
Stabilized DBS was prepared according to Example 1 except that 3% by weight of N, N-diethanol-12-hydroxystearylamine was used as the alkaline organic amine compound for pm.
The generated aldehyde amount was 10 ppm and the isomer amount was 0.01%.

Comparative Example 1 When a Me-DBS crude product which was not subjected to solvent refining treatment and to which an alkali metal compound and an alkaline organic amine compound were not added was measured according to Example 1, the amount of generated aldehyde was 1,400 ppm, and the amount of isomers was found. Was 0.9%.

Comparative Example 2 Only the solvent refining treatment is carried out in the same manner as in Example 1, and the alkali metal compound and the alkaline organic amine compound are not added.
When the purified Me-DBS product was measured according to Example 1, the amount of generated aldehyde was 1,100 ppm and the amount of isomers was 0.
It was 02%.

Comparative Example 3 5% by weight of N, N-diethanolstearylamine was used as an alkaline organic amine compound without solvent purification treatment.
When the added Me-DBS crude product was measured according to Example 1, the generated aldehyde amount was 1,250 ppm and the isomer amount was 0.95%.

Comparative Example 4 When the Me-DBS crude product prepared according to Example 1 was measured except that the solvent refining treatment was not performed, the amount of generated aldehyde was 1,300 ppm and the amount of isomer was 0.95%.

Comparative Example 5 Cyclohexane / acetone (8/2) 150 without solvent purification
Disperse 10 g of Me-DBS crude product in ml and add 80 g of potassium stearate.
After adding 0 ppm and stirring at 60 ° C. for 1 hour, the product was hipped and dried. The amount of aldehyde generated by this heating test was 990 ppm, and the amount of isomers was 0.95%.

Comparative Example 6 Dispersing in a solvent in the same manner as in Comparative Example 5, adding kalimu stearate, and performing solvent purification by further filtering,
Dried. The generated aldehyde amount was 385 ppm and the isomer amount was 0.05%.

[Advantages of the Invention] The DBS composition according to the present invention is very stable because it is little colored even when heated and the generation of aldehyde due to decomposition is suppressed. Therefore, for example, when this is applied as a nucleating agent for a crystalline resin, the work environment is improved because the generation of odor during molding of the resin is greatly suppressed, and it can also be used for tableware containers without color unevenness. A molded product can be obtained.

Claims (1)

[Claims] 1. A dibenzylidene sorbitol represented by the general formula (I), wherein the regioisomer of the dibenzylidene sorbitol is reduced to 0.2% by weight or less. A stabilized dibenzylidene sorbitol composition comprising an amine compound. [In the formula, X and X ′ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a halogen atom. m and n are the same or different and are 1 to
Represents an integer of 5. p represents 0 or 1. ]