JP2795018B2 - Rosin ester production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a rosin ester which is colorless, odorless and excellent in stability.

[0002]

2. Description of the Related Art Hitherto, rosin esters have been used for various purposes such as tackifiers for adhesives, modifiers for rubbers and various plastics, raw materials for traffic paints, and chewing gum base materials. However, the rosin ester was colored yellow or yellowish in appearance, and was not satisfactory in terms of odor, heat stability, weather resistance (hereinafter referred to as stability), and the like.

[0003] Therefore, in order to solve the above-mentioned disadvantages of the rosin ester, disproportionated rosin ester and hydrogenated rosin obtained by using a disproportionated rosin or hydrogenated rosin having excellent thermal stability as a starting material. Rosin esters are also commercially available, but all of them are insufficient in color tone, stability and the like.

Japanese Patent Publication No. 45-33771 and Japanese Patent Publication No. 49-20599 describe a method of disproportionating a rosin or a rosin compound with a specific organic sulfur compound, which was obtained by this method. The disproportionated rosin ester is insufficient in color, odor and stability.

Japanese Unexamined Patent Publication (Kokai) No. 55-9605 discloses a method for producing a rosin ester having excellent stability by purifying a disproportionated rosin to remove a high molecular weight substance and an unsaponifiable substance contained in a raw rosin. A method of esterifying the obtained purified disproportionated rosin and alcohol after removal is described. However, although the rosin ester obtained by this method is lighter and more stable than the conventional rosin ester, it is colored in the esterification step and the stability to heat coloring is not satisfactory, and it is still an improvement. There is room.

Further, JP-A-59-230072 discloses a method for producing a rosin ester having a light color and good stability, which comprises distilling a rosin ester in the presence of a specific organic sulfur compound having both disproportionation ability and lightening ability. Although a method of esterifying purified rosin with alcohol is described, the rosin ester obtained by this method is still unsatisfactory in color tone and stability, and furthermore, sulfur odor during heating due to organic sulfur compounds. There is a problem that is strong.

[0007] As described above, none of the conventional rosin esters can simultaneously satisfy all the performances of color, odor and stability, and they are completely competitive with hydrogenated petroleum resins used for the same purpose. It wasn't good.

Japanese Patent Application Laid-Open No. 63-186783 discloses a method for producing a rosin ester which is colorless and has good stability. However, this method requires a hydrogenation step, so that a high pressure resistance reaction is required. The use of the apparatus and the consumption of a large amount of hydrogen have the disadvantage of significantly increasing the production cost.

[0009]

SUMMARY OF THE INVENTION In view of the above situation, the present inventors have developed a rosin ester which has been further improved in various properties such as color tone, odor and stability of a conventionally known rosin ester.
Intensive study was conducted for the purpose of developing a new manufacturing method that can be provided at a relatively low price.

[0010]

In view of the above problems, the present inventors focused on various conditions such as a starting material rosin species, a purification operation, an esterification and a dehydrogenation reaction, and so on to improve the above various properties. As a result of investigations for improvement, a specific raw material rosin was used, further purified, and then passed through a specific reaction process, thereby solving the above-mentioned problems and achieving excellent performances meeting the objectives. A novel production method capable of obtaining a rosin ester having the following formula:

That is, the present invention relates to a method for producing a rosin ester, which comprises subjecting a purified product of a disproportionated rosin to an esterification reaction with an alcohol, followed by a dehydrogenation reaction.

The present invention provides a rosin ester which is almost colorless in appearance and excellent in odor and stability upon heating without adding any stabilizer such as an antioxidant and a coloring inhibitor. The rosin ester obtained by the method is intended to wipe out stereotypes formed from various properties of the conventional rosin ester, and is represented by a light-colored resin. It is no inferior to hydrogenated petroleum resins. Moreover, it retains the characteristics of a rosin derivative (that is, wide compatibility with various polymers).

The present invention comprises three steps: a step of purifying disproportionated rosin, a step of esterification with various alcohols, and a step of dehydrogenating the esterified product.

In the present invention, it is essential to use disproportionated rosin as a starting material rosin in view of the color tone and stability of the obtained rosin ester. The disproportionated rosin is a disproportionation reaction product of gum rosin, wood rosin, and tall oil rosin containing resin acids such as abietic acid, parastolic acid, neoabietic acid, pimaric acid, isopimaric acid, and dehydroabietic acid as main components. Say.

The disproportionated rosin used in the present invention can be easily produced by subjecting the raw material rosin to a known disproportionation reaction. That is, rosin is heated and reacted in the presence of a disproportionation catalyst. Examples of the disproportionation catalyst include various known catalysts such as supported catalysts such as palladium carbon, rhodium carbon, and platinum carbon, metal powders such as nickel and platinum, and iodides such as iodine and iron iodide. The amount of the catalyst to be used is generally 0.01 to 5% by weight, preferably 0.01 to 1.0% by weight, based on rosin, and the reaction temperature is 100 to 300 ° C, preferably 150 to 290 ° C. .

In the present invention, it is necessary to further purify the disproportionated rosin, wherein the purification is caused by a peroxide contained in the rosin before the disproportionation or the rosin after the disproportionation. It means removing high molecular weight substances considered to be considered and unsaponifiable substances originally contained in the rosin. Specifically, operations such as distillation, recrystallization, and extraction may be performed, and purification by distillation is preferable from an industrial viewpoint. In the case of distillation,
Usually, the temperature is appropriately selected from the range of 200 to 300 ° C. and the pressure of 1 to 10 mmHg in consideration of the distillation time. In the case of recrystallization, for example, disproportionated rosin is dissolved in a good solvent, then the solvent is distilled off to form a concentrated solution, and a poor solvent is added to this solution. Good solvents include benzene, toluene, xylene, chloroform, lower alcohols, ketones such as acetone, lower alkyl acetates such as ethyl acetate, and the like, and poor solvents include n-hexane, n-heptane, cyclohexane, isooctane and the like. No. Further, in the purification, the raw material rosin is converted into an aqueous alkali solution using alkaline water, and the insoluble unsaponifiable substance is extracted with an organic solvent, and then the aqueous layer is neutralized to obtain a purified raw material rosin.

In the present invention, then, the purified disproportionated rosin is subjected to an esterification step with various alcohols. For the esterification reaction, ordinary conditions can be employed as they are. For example, the purification may be carried out by heating purified disproportionated rosin and the following various alcohols to 150 to 300 ° C. in an inert gas stream, and removing generated water out of the system. Examples of the alcohol used here include monohydric alcohols such as n-octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, and lauryl alcohol; dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and neopentyl glycol; glycerin; Trihydric alcohols such as trimethylolethane, trimethylolpropane and cyclohexanedimethanol; and tetrahydric alcohols such as pentaerythritol and diglycerin. The reaction does not necessarily require an esterification catalyst. However, in order to shorten the reaction time, an acid catalyst such as acetic acid or paratoluenesulfonic acid, a hydroxide of an alkali metal such as calcium hydroxide, calcium oxide, or an oxidizing agent is used. Metal oxides such as magnesium can also be used.

The object of the present invention can be obtained by subjecting the purified disproportionated rosin ester obtained through the above step to a final step of dehydrogenating the esterified product. Here, dehydrogenation means that the composition ratio of the resin acid components dihydroabietic acid and dehydroabietic acid in the disproportionated rosin ester changes, and specifically, the dihydroabietic acid component is dehydrogenated and dehydrogenated. It becomes abietic acid, which means that the content of dehydroabietic acid increases.
According to the above-mentioned dehydrogenation reaction, 2 mol of hydrogen is produced from 1 mol of dihydroabietic acid component, and the produced hydrogen has the ability to effectively reduce peroxides present in trace amounts in the esterified product of purified disproportionated rosin. Having. That is, an almost colorless rosin ester is obtained based on the reducing action.

The conditions for the dehydrogenation reaction are not particularly limited, and ordinary conditions can be employed. For example, in the presence of a dehydrogenation catalyst, the rosin ester has an initial hydrogen pressure of 10 kg in a closed container.
/ Cm ² , preferably less than 5 kg / cm ² , and a reaction temperature of 100 to 300 ° C, preferably 200 to 280 ° C. Hydrogen is substantially unnecessary because it is a dehydrogenation reaction, but the initial hydrogen pressure is set to 10 kg by the intention of utilizing the produced hydrogen for the reduction of peroxide as described above.
/ Cm ² , and the pressure may be adjusted by the self-pressure of generated hydrogen or by slightly supplying hydrogen from outside. You. As the dehydrogenation catalyst, various known catalysts can be used without any particular limitation, and preferred examples include palladium-based, rhodium-based, and platinum-based catalysts. The catalyst is usually used by being supported on a carrier such as silica, alumina and carbon. The amount of the catalyst used (in terms of metal)
Is usually about 0.01 to 5% by weight, preferably 0.1 to 3% by weight, based on the rosin ester.

The resin acid composition of the rosin ester obtained by the above method varies slightly depending on the hydrogen supply pressure, but is usually 15 to 35% by weight of the dihydro form and 85% of dehydroabietic acid.
６５65% by weight. The peroxide value of the obtained rosin ester is usually 1 or less.

The rosin ester obtained by the method of the present invention has an almost colorless color tone in appearance, and is excellent in various properties such as odor, stability and compatibility upon heating. It can be suitably used as a tackifier for adhesives or hot melt adhesives, a modifier for rubbers and various plastics, a raw material for traffic paint, a chewing gum base material, a modifier for inks and paints,
The commercial value of the final product in these applications can be improved.

[0022]

According to the present invention, a rosin ester having significantly improved various properties such as color tone, odor and stability can be provided at a relatively low price as compared with conventionally known rosin esters.

[0023]

EXAMPLES Hereinafter, the method of the present invention will be described in more detail with reference to Examples and Comparative Examples, but it goes without saying that the present invention is not limited to these.

Example 1 (1) Disproportionation Reaction 0.3 g of 5% palladium carbon was added as a catalyst to 1000 g of unpurified Chinese gum rosin having an acid value of 172, a softening point of 75 ° C. and a color tone of Gardner 6 under a nitrogen blanket. The mixture was stirred at 4 ° C. for 4 hours to carry out a disproportionation reaction, whereby disproportionated rosin having an acid value of 157, a softening point of 77 ° C. and a color tone of Gardner 8 was obtained. (2) Purification The disproportionated rosin was distilled under a reduced pressure of 3 mmHg under a nitrogen seal, and the obtained main fraction was used as purified disproportionated rosin.

[0025]

[Table 1]

(3) Esterification 500 g of a purified rosin having an acid value of 178, a softening point of 83 ° C., and a color tone Gardner 4 obtained by the above-mentioned distillation was placed in a 1-liter flask, and heated to 180 ° C. under a nitrogen seal. Then, after adding 60 g of glycerin at 200 ° C. with melt stirring, 2
The temperature was raised to 80 ° C., and the esterification reaction was carried out at the same temperature for 12 hours. The acid value was 3.4, the softening point was 99 ° C., and the color tone was 5%.
515 g of purified disproportionated rosin ester was obtained.

(4) Dehydrogenation The purified disproportionated rosin ester 200 obtained in the above (3)
g and 1 g of 5% palladium carbon were charged into a 1 liter shaking autoclave, oxygen in the system was removed, and then the system was pressurized to 0.5 kg / cm ² with hydrogen and heated to 270 ° C. For 3 hours to obtain 197 g of a rosin ester having an acid value of 8.5, a softening point of 99 ° C. and a color tone Gardner of 1 or less (Hazen color 150).

Example 2 (1) The purified disproportionated rosin 500 obtained in (2) of Example 1
g into a 1 liter flask,
The temperature was raised to 0 ° C., and glycerin 43
g and 33 g of diethylene glycol, and then 270
C., and the esterification reaction was carried out at the same temperature for 12 hours, to obtain 517 g of a purified disproportionated rosin ester having an acid value of 3.7, a softening point of 75.degree. (2) (1) Example 2 Dee was purified disproportionated rosin ester
Were charged Le 200g and 5% palladium on carbon 1g to 1 liter shaking autoclave of Example 1 (4)
A dehydrogenation reaction was carried out under the same conditions as described above, and the acid value was 7.6, the softening point was 74 ° C., the color tone was Gardner 1 or less (Hazen Color 1
198 g of the rosin ester of 20) was obtained.

Example 3 (1) The purified disproportionated rosin 500 obtained in (2) of Example 1
g into a 1 liter flask,
The temperature was raised to 0 ° C, and diglycerin 7 was added at 200 ° C under melt stirring.
After adding 9 g, the temperature was raised to 280 ° C., and an esterification reaction was carried out at the same temperature for 13 hours to obtain an acid value of 5.5 and a softening point of 103.
℃, Purified disproportionated rosin ester 51 of color tone Gardner 7
7 g were obtained. (2) Example 3 (1) Dee was purified disproportionated rosin ester
Were charged Le 200g and 5% palladium on carbon 1g to 1 liter shaking autoclave of Example 1 (4)
A dehydrogenation reaction was carried out under the same conditions as described above to obtain 198 g of a rosin ester having an acid value of 9.8, a softening point of 104 ° C. and a color tone Gardner of 1 or less (Hazen Color 170).

Comparative Example 1 The unpurified disproportionated rosin obtained in (1) of Example 1 was used in Example 1.
An esterification reaction was carried out in the same manner as in (3) to obtain 505 g of unpurified disproportionated rosin ester having an acid value of 4.5, a softening point of 93 ° C. and a color tone of Gardner 10. Then, the unpurified disproportionated rosin ester was subjected to a dehydrogenation reaction in the same manner as in Example 1 (4) to obtain 197 g of a rosin ester of Gardner 7 having an acid value of 8.5, a softening point of 95 ° C.

The methods for measuring various performances are as follows. The results are shown in Tables 2 and 3. (Peroxide value) Conforms to the standard fat and oil analysis test method (2.4.12-86) of the Japan Association of Fats and Chemicals. (Resin acid composition in rosin ester) Each rosin ester before and after the dehydrogenation reaction is hydrolyzed, and the hydrolyzate is subjected to AST.
It was measured by gas chromatography according to MD3008-82. (Heating stability) 10 g of a sample is placed in a test tube having an inner diameter of 1.5 cm and a height of 15 cm, and is left in a circulating drier at 200 ° C. without a lid to observe changes in color tone (gardner) with time. Observed. (Weather resistance) Weight increase when 2.0 g of resin adjusted to a particle size of 60 to 100 mesh is placed in an ointment can having an inner diameter of 5.6 cm and a height of 1 cm and irradiated with a 400 W mercury lamp from a distance of 40 cm for 15 hours (oxygen absorption) (Amount) and color tone (gardner) were observed. Incidentally, the color tone is evaluated by evaluation in a 50% toluene solution.

[0032]

[Table 2]

[0033]

[Table 3]

Claims (4)

(57) [Claims] 1. A method for producing a rosin ester, which comprises subjecting a purified product of disproportionated rosin to an esterification reaction with an alcohol, followed by a dehydrogenation reaction. 2. The method for producing a rosin ester according to claim 1, wherein the dehydrogenation reaction catalyst is a palladium, rhodium or platinum catalyst. 3. In the dehydrogenation reaction, the reaction pressure is 10
Kg / cm ² less than the preparation of rosin esters according to claim 1. 4. The method for producing a rosin ester according to claim 1, wherein the resin acid composition in the rosin ester after the dehydrogenation reaction is 15 to 35% by weight of a dihydro compound and 85 to 65% by weight of dehydroabietic acid.