JPH0711194A - Production of colorless rosin ester - Google Patents

Abstract

PURPOSE:To produce a colorless rosin ester markedly improved in the properties such as color tone, odor and stability as compared with a conventional known rosin ester. CONSTITUTION:This process for producing a colorless rosin ester comprises esterifying purified hydrogenated rosin with an alcohol and hydrogenating the reactional product in the presence of a dehydrogenation catalyst. Another process for producing a colorless rosin ester wherein the esterification of the purified hydrogenerated rosin with an alcohol and the dehydrogenation of the reactional product in the presence of a dehydrogenation catalyst are performed simultaneously. Thus, rosin esters markedly improved in the properties such as color tone, odor and stability can be obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD 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 Rosin esters have hitherto been used in various applications such as tackifiers for adhesives, modifiers for rubbers and various plastics, raw materials for traffic paints, chewing gum base materials and the like. However, the rosin ester is colored yellow to yellowish brown in its appearance, and is not satisfactory in terms of odor, heat stability, weather resistance (hereinafter referred to as stability) and the like.

In order to solve the above-mentioned drawbacks of the rosin ester, a disproportionated rosin ester or a hydrogenated rosin ester obtained by using a disproportionated rosin or a hydrogenated rosin having excellent thermal stability as a starting material is also used. Although they are commercially available, they are all insufficient in terms of color tone and stability.

JP-B-45-33771 and JP-B-49-20599 describe a method of disproportionating a rosin or a rosin-based compound with a specific organic sulfur compound, which was obtained by this method. Disproportionated rosin is also insufficient in terms of color tone, odor and stability.

As a method for producing a highly stable rosin ester, JP-A-55-9605 discloses a method of purifying disproportionated rosin to obtain high molecular weight substances and unsaponifiable substances contained in raw rosin. After removal, a method for esterifying the obtained purified disproportionated rosin with alcohol 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 against heat coloring is not satisfactory, and there is still room for improvement. There is.

Further, JP-A-59-230072 discloses a method for producing a rosin ester having a light color and good stability, which is distilled in the presence of a specific organic sulfur compound having both disproportionation ability and lightening ability. A method of esterifying purified rosin with alcohol has been described, but the rosin ester obtained by this method is still unsatisfactory in terms of color tone and stability, and the sulfur odor during heating due to the organic sulfur compound is still present. 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 tone, odor and stability, and they compete with each other in comparison with hydrogenated petroleum resins used for the same purpose. It wasn't profitable.

[0008]

In view of the above-mentioned circumstances, the present inventors have proposed a rosin ester which has been further improved in the color tone, odor and stability of the conventionally known rosin ester.
An intensive study was conducted for the purpose of developing a new manufacturing method that can be provided at a relatively low price.

[0009]

In view of the above-mentioned problems, the present inventors have focused on various conditions such as a starting material rosin species as a starting material, a refining operation, an esterification and a dehydrogenation reaction to achieve the above-mentioned various performances. As a result of studies to improve, by using a specific raw material rosin, further purifying it, and then passing it through a specific reaction step, the above-mentioned problems were solved, and various excellent performances meeting this objective were obtained. We have found a new process for obtaining a rosin ester having

That is, the present invention is a colorless rosin characterized in that a purified hydrogenated rosin (hereinafter referred to as rosin (A)) is subjected to an esterification reaction with an alcohol, and then subjected to a dehydrogenation reaction in the presence of a dehydrogenation catalyst. It relates to a method for producing an ester. Further, the present invention relates to a method for producing a colorless rosin ester, which comprises simultaneously advancing a dehydrogenation reaction in the presence of a dehydrogenation catalyst when esterifying a rosin (A) and an alcohol.

The present invention provides a rosin ester which is almost colorless in appearance and has excellent odor and stability when heated without adding any stabilizer such as an antioxidant and a coloring inhibitor. The rosin ester obtained by the method is one that eliminates the stereotype formed from the various properties of conventional rosin esters, and is represented by a light-colored resin. Compared with hydrogenated petroleum resin, it is in no way inferior. Moreover, it retains the characteristic of being a rosin derivative (that is, having a wide compatibility with various polymers).

In the present invention, rosin (A) which is the following specific rosin compound is essentially used as a starting material from the viewpoints of color tone, stability and the like of the rosin ester finally obtained. The rosin (A) is obtained by purifying an unpurified hydrogenated rosin. That is, after a partial or complete hydrogenation reaction of gum rosin, wood rosin, or tall oil rosin containing abietic acid, parastophosphoric acid, neoabietic acid, pimaric acid, isopimaric acid, resin acid such as dehydroabietic acid as a main component, and wood oil rosin, It is obtained by further purifying this.

In the hydrogenation reaction, known hydrogenation reaction conditions can be appropriately selected. That is, it is usually 10 to 200 Kg / cm ² , preferably 50 to 15 in the presence of a hydrogenation catalyst.
It is carried out by heating the crude rosin under a hydrogen pressure of 0 Kg / cm ² . As the hydrogenation catalyst, various known catalysts such as supported catalysts such as palladium carbon, rhodium carbon and platinum carbon, metal powders such as nickel and platinum, iodide such as iodine and iron iodide can be exemplified. The amount of the catalyst used is usually 0.01 to 5% by weight based on rosin,
It is preferably 0.01 to 1.0% by weight, and the reaction temperature is 100 to 300 ° C, preferably 150 to 290 ° C. The above-mentioned purification is to remove a high molecular weight substance considered to be generated from a peroxide contained in a rosin before hydrogenation or a rosin after hydrogenation, and an unsaponifiable substance originally contained in the rosin. Means Specifically, operations such as distillation, recrystallization and extraction may be performed, and purification by distillation is industrially preferable. If distilled, a temperature of 20
It is appropriately selected from the range of 0 to 300 ° C. and the pressure of 1 to 10 mmHg in consideration of the distillation time. Recrystallization can be performed, for example, by dissolving crude hydrogenated rosin in a good solvent, distilling off the solvent to form a concentrated solution, and adding a poor solvent to this solution. Examples of good solvents include ketones such as benzene, toluene, xylene, chloroform, lower alcohols and acetone, and acetic acid esters such as ethyl acetate, and examples of poor solvents include n-hexane and n-hexane.
Heptane, cyclohexane, isooctane and the like can be mentioned. Furthermore, the crude hydrogenated rosin may be made into an alkaline aqueous solution using alkaline water, the insoluble unsaponifiable matter may be extracted with an organic solvent, and then the aqueous layer may be neutralized, thereby obtaining rosin (A). You can also

In the present invention, a method of esterifying a rosin (A) with an alcohol and then carrying out a dehydrogenation reaction of the esterified product (C) in the presence of a dehydrogenation catalyst (hereinafter referred to as the first method), or By adopting a method in which the esterification and the dehydrogenation reaction proceed simultaneously in the presence of a dehydrogenation catalyst for rosin (A) and alcohol (hereinafter referred to as the second method), the target product can be obtained.

In the esterification reaction in the first method, the usual conditions can be employed as they are, for example, the raw material rosin (A) and the following alcohol (B) under an inert gas stream.
Is usually heated to 150 to 300 ° C. and the produced water is removed to the outside of the system. Specific examples of the alcohol (B) 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. , Trimethylolethane, trimethylolpropane, cyclohexanedimethanol and other trihydric alcohols; pentaerythritol, diglycerin and other tetrahydric alcohols. The reaction does not necessarily require an esterification catalyst, but in order to reduce the reaction time, acetic acid, an acid catalyst such as p-toluenesulfonic acid, an alkali metal hydroxide such as calcium hydroxide, calcium oxide, or an oxide. It is also possible to use a metal oxide such as magnesium.

In the first method, the desired product can be obtained by subjecting it to the final step of dehydrogenating the esterified product (C). The dehydrogenation reaction conditions are not particularly limited and usual conditions can be adopted. For example, in the presence of a dehydrogenation catalyst, the rosin (A) has a hydrogen initial pressure of 10 kg / cm ^{2 in} a closed container.
Less, preferably less than 5 Kg / cm ² , reaction temperature 10
The heating may be performed in the range of 0 to 300 ° C, preferably 200 to 280 ° C. Hydrogen is essentially unnecessary because it is a dehydrogenation reaction, but the initial hydrogen pressure is set to 10 kg / cm ^{2 in} order to utilize the produced hydrogen for the reduction of peroxide as described above.
However, the pressure may be adjusted by the self-pressure of the produced hydrogen or by slightly supplying hydrogen from the outside. As the above dehydrogenation catalyst, various known catalysts can be used without particular limitation, but palladium-based, rhodium-based, and platinum-based catalysts are preferred. The catalyst is usually used by supporting it on a carrier such as silica or carbon. The amount of the catalyst used is usually 0.0 with respect to the esterified product (C).
It is about 1 to 5% by weight, preferably 0.02 to 2% by weight. In the dehydrogenation reaction, an alicyclic hydrocarbon such as cyclohexane or decalin or an aromatic hydrocarbon such as toluene or xylene can be appropriately used as a solvent.

In the case of the second method, the esterification and dehydrogenation reactions proceed at the same time, which is superior to the first method in that the manufacturing process can be simplified and the product cost can be reduced. The esterification and dehydrogenation reactions themselves are not different. Therefore, in the second method as well, the same conditions as in the first method can be adopted for both the esterification and dehydrogenation reactions, but from the viewpoint of easy removal of the water produced in the esterification reaction to the outside of the system, the atmospheric pressure is used. It is preferable to proceed the second method in the vicinity. Further, during the reaction, in order to prevent the color tone of the obtained rosin ester from being lowered, it is preferable to carry out the reaction under an inert gas stream, preferably under a hydrogen stream.

The resin acid composition in the colorless rosin ester obtained by the first method and the second method slightly changes depending on the hydrogen supply pressure, but it is usually less than 1% of abietic acid, 10 to 50% by weight of tetrahydro compound, and dihydro. The body is 10 to 40% by weight, and dehydroabietic acid is 20 to 60% by weight. The peroxide value is usually 1 or less.

When unpurified hydrogenated rosin is used as a starting material, the target product of the present invention cannot be obtained even through the first and second methods.

According to the production method of the present invention, an extremely light-colored rosin ester having essentially a Hazen color tone level can be obtained, but if necessary, a stabilizer such as various known organophosphorus compounds can be used in each production step of the present invention. It goes without saying that compounds can be added.

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 upon heating, stability and compatibility, so that it is pressure sensitive. 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 paints, a chewing gum base material, a modifier for inks and paints, etc. It can improve the commercial value of the product.

[0022]

Industrial Applicability According to the present invention, it is possible to provide a rosin ester which is remarkably improved in various properties such as color tone, odor and stability as compared with conventionally known rosin esters at a relatively low cost.

[0023]

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

Example 1 (1) Hydrogenation reaction An acid value of 171 and a softening point of 76 in a 3 liter autoclave.
℃, unrefined Chinese gum rosin 100 with color Gardner 6
0 g and 2 g of 5% palladium carbon (water content 50%) as a hydrogenation catalyst were charged to remove oxygen in the system, and the system was pressurized to 100 Kg / cm ² with hydrogen, and then 2 with stirring.
The temperature was raised to 60 ° C., and hydrogenation reaction was carried out at the same temperature for 3 hours to obtain an unpurified hydrogenated rosin having an acid value of 167, a softening point of 74 ° C. and a color tone Gardner 5. (2) Purification The unpurified hydrogenated rosin was distilled under a nitrogen blanket under a reduced pressure of 3 mmHg to give a main distillate shown in Table 1 having an acid value of 175.2, a softening point of 83 ° C., and a general constant of color tone Gardner 2. It was purified hydrogenated rosin.

[0025]

[Table 1]

(3) Esterification 500 g of purified hydrogenated rosin having an acid value of 175.2, a softening point of 83 ° C. and a color tone Gardner 2 obtained by the above distillation was placed in a 1 liter flask and heated to 180 ° C. under a nitrogen seal. After heating and adding 58 g of glycerin at 200 ° C. under melting and stirring, the temperature was raised to 270 ° C., and the esterification reaction was carried out at the same temperature for 12 hours to obtain an acid value of 7.0, a softening point of 95 ° C., and a color tone of Gardner 3. A hydrogenated rosin ester was obtained.

(4) Dehydrogenation Purified hydrogenated rosin ester 200 obtained in (3) above
g and 0.4 g of 5% palladium carbon were charged into a 1 liter shaking autoclave to remove oxygen in the system, and the system was pressurized to 0.5 Kg / cm ² with hydrogen to 270
The temperature is raised to ℃, and the dehydrogenation reaction is performed at the same temperature for 3 hours.
A rosin ester having an acid value of 8.5, a softening point of 96 ° C. and a color tone of Gardner 1 or less (Hazen color 100) was obtained.

Example 2 (1) Hydrogenation reaction In Example 1 (1), 5% palladium (water content 50
(%) Was changed to 0.7 g to carry out hydrogenation reaction in the same manner as in Example 1 (1) to obtain an unpurified hydrogenated rosin having an acid value of 169, a softening point of 75 ° C. and a color tone Gardner 6. (2) Purification The unpurified hydrogenated rosin was distilled under reduced pressure under the same conditions as in Example 1 (2) to give an acid value of 175.5, a softening point of 85.5 ° C., and a table having a general constant of color tone Gardner 2-3. The main distillate shown in 2 was purified hydrogenated rosin.

[0029]

[Table 2]

(3) Esterification The acid value obtained by the distillation is 175.5 and the softening point is 85.5.
C., 500 g of purified hydrogenated rosin with color tone Gardner 2-3
According to (3) of Example 1 except that the acid value was 6.5,
A purified hydrogenated rosin ester having a softening point of 95 ° C. and a color tone of Gardner 4 was obtained. (4) Dehydrogenation Purified hydrogenated rosin ester 200 obtained in (3) above
g and 0.4 g of 5% palladium carbon were charged into a 1 liter shaking autoclave to remove oxygen in the system, and the system was pressurized to 0.5 Kg / cm ² with hydrogen to 270
The temperature is raised to ℃, and the dehydrogenation reaction is performed at the same temperature for 3 hours.
A rosin ester having an acid value of 8.0, a softening point of 97 ° C. and a color tone of Gardner 1 or less (Hazen color 100) was obtained.

Example 3 500 g of the purified hydrogenated rosin obtained in (2) of Example 1
Transfer to a liter flask, raise the temperature to 180 ° C. under a nitrogen blanket, add 43 g of glycerin and 33 g of diethylene glycol at 200 ° C. under melting and stirring, then raise the temperature to 270 ° C., and perform the esterification reaction at the same temperature for 12 hours. A purified hydrogenated rosin ester having an acid value of 3.4, a softening point of 75.0 ° C. and a color tone of Gardner 3 was obtained. Then, 200 g of the purified hydrogenated rosin ester was subjected to a dehydrogenation reaction in the same manner as in (4) of Example 1 to give a rosin having an acid value of 7.6, a softening point of 74 ° C., and a color tone of Gardner 1 or less (Hazen color 60). I got an ester.

Example 4 500 g of the purified hydrogenated rosin obtained in (2) of Example 1 and 2 g of 5% palladium carbon (water content 50%) as a dehydrogenation catalyst were placed in a 1 liter flask and sealed under hydrogen. The temperature was raised to 180 ° C., 58 g of glycerin was added at 200 ° C. under melting and stirring, and then the temperature was raised to 270 ° C., the esterification reaction and the dehydrogenation reaction were simultaneously carried out for 12 hours at the same temperature, and the acid value was 3.7. A rosin ester having a softening point of 96 ° C. and a color tone of Gardner 1 or less (Hazen color 150) was obtained.

Comparative Example 1 An acid value of 4.5 was obtained according to (3) of Example 1 except that 500 g of the unpurified hydrogenated rosin obtained in (1) of Example 1 was used.
A crude hydrogenated rosin ester having a softening point of 93 ° C. and a color tone of Gardner 8 was obtained. Then, 200 g of the unpurified hydrogenated rosin ester was subjected to a dehydrogenation reaction in the same manner as in (4) of Example 1 to obtain a rosin ester having an acid value of 8.5, a softening point of 95 ° C. and a color tone Gardner 6.

Comparative Example 2 According to Example 4, except that 500 g of the unpurified hydrogenated rosin obtained in (1) of Example 1 was used, the acid value was 4.0 and the softening point was 9
A rosin ester having a color tone of Gardner 7 was obtained at 6 ° C.

The methods of measuring various performances are as follows. The results are shown in Tables 4 and 5. (Resin Acid Composition in Rosin) Each rosin ester before and after the dehydrogenation reaction is hydrolyzed, and the hydrolyzate is treated with ASTM D30.
Gas chromatography measurement was performed according to 08-82. (Heating stability) 10 g of the sample was put into a test tube having an inner diameter of 1.5 cm and a height of 15 cm, and the sample was allowed to stand in a circulating air dryer at 200 ° C. without a lid to change the color tone (gardner) with time. I observed. (Weather resistance) 2.0 g of resin having a uniform particle size of 60 to 100 mesh was placed in an ointment can having an inner diameter of 5.6 cm and a height of 1 cm, and a weight increase (oxygen absorption when a 400 W mercury lamp was irradiated from a distance of 40 cm for 15 hours) The amount and the color tone (gardner) were observed. The color tone is evaluated by a 50% toluene solution.

[0036]

[Table 4]

[0037]

[Table 5]

Claims (6)

[Claims] 1. A process for producing a colorless rosin ester, which comprises subjecting a purified hydrogenated rosin and an alcohol to an esterification reaction, and then performing a dehydrogenation reaction in the presence of a dehydrogenation catalyst. 2. A process for producing a colorless rosin ester, which comprises simultaneously advancing a dehydrogenation reaction in the presence of a dehydrogenation catalyst when esterifying a purified hydrogenated rosin with an alcohol. 3. The method according to claim 1, wherein the dehydrogenation catalyst is a palladium, rhodium or platinum-based catalyst. 4. The method according to claim 2, wherein the dehydrogenation catalyst is a palladium, rhodium or platinum-based catalyst. 5. A reaction pressure of 10 in the dehydrogenation reaction.
The method according to claim 1, wherein the production method is less than Kg / cm ² . 6. The production method according to claim ² , wherein the reaction pressure is less than 10 kg / cm ² when the esterification and dehydrogenation reactions are simultaneously advanced.