JP2001316330A - Method for producing colorless rosin ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a colorless, odorless and highly stable rosin ester which simultaneously improves the various properties, such as color tone, odor and stability, of conventional rosin esters. SOLUTION: This method for producing the colorless rosin ester, characterized by esterifying purified hydrogenated rosin with an alcohol and then hydrogenating the esterification product in the presence of a hydrogenation catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a colorless rosin ester which is colorless, odorless and excellent in stability.

[0002]

2. Description of the Related Art Rosin esters are used in various applications such as tackifiers for adhesives, modifiers for rubbers and various plastics, resins for traffic paints, and chewing gum base materials. However, rosin esters generally have a poor color tone and are colored yellow or tan. Further, it lacked stability (hereinafter referred to as stability) against deterioration of color tone due to oxidation due to heating or irradiation with sunlight, and was not satisfactory in terms of odor and the like.

[0003] Rosin esters which have been solved to some extent by using disproportionated rosin or hydrogenated rosin having excellent stability as a raw material rosin compound are commercially available.
Their color tone and stability are not satisfactory.

Japanese Patent Application Laid-Open No. 55-9605 discloses a method for producing a rosin ester having excellent stability by esterifying a disproportionated rosin distilled and purified with an alcohol. However, although the rosin ester obtained by this method has relatively good stability as compared with conventional rosin esters, it is not satisfactory. There is also a problem that the rosin ester is colored during heating in the esterification step.

JP-A-59-230072 discloses a method for producing a rosin ester having excellent stability and color tone, which comprises dissolving a disproportionated rosin compound purified by distillation and an alcohol,
A method for esterification in the presence of a specific organic sulfur compound having both disproportionation ability and lightening ability is described. However, the rosin ester obtained by this method still has room for improvement in terms of stability, and is generated upon heating.
A new problem is the strong sulfur odor caused by organic sulfur compounds.

As described above, all of the rosin esters obtained by the conventional production methods are uneasy in various properties such as color tone, stability and odor, and a method of producing a rosin ester satisfying all these various properties has been desired. .

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a colorless, odorless and stable rosin ester having improved color tone, odor and various properties of a conventional rosin ester at the same time. And

[0008]

Means for Solving the Problems The present inventors have focused on various conditions such as the starting material rosin species as a starting material, purification operation, esterification and hydrogenation reaction steps, and have studied to improve the above-mentioned various performances. As a result, by using a purified hydrogenated rosin obtained by purifying and hydrogenating a specific rosin compound as a raw material, and then passing through a specific reaction process, a rosin ester having significantly improved color tone, odor and stability is provided. A new manufacturing method was found.

That is, the present invention relates to a method for producing a colorless rosin ester, which comprises subjecting a purified hydrogenated rosin to an alcohol and subjecting the ester to a hydrogenation reaction in the presence of a hydrogenation catalyst.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel process for producing a rosin ester which is colorless, odorless and has excellent stability. Moreover, this production method does not require any stabilizers such as antioxidants and anti-coloring agents which are generally used for the purpose of enhancing the stability of the product. The rosin ester obtained by this method is almost colorless in appearance as compared with a conventional rosin ester, and has no inferiority to a hydrogenated petroleum resin represented by a light-colored resin. In addition, the rosin ester has a wide compatibility with various polymers, which is an excellent feature of the rosin derivative.

The purified hydrogenated rosin used in the present invention is obtained by hydrogenating various rosin compounds to obtain a hydrogenated rosin compound and then purifying the same to obtain a colorless rosin ester satisfying various properties such as color tone, odor and stability. For this purpose, it is essential to use this purified hydrogenated rosin as a starting material, and even if unpurified hydrogenated rosin is used as a starting material, the desired rosin ester cannot be obtained.

Examples of various rosin compounds used in the production of hydrogenated rosin include gum rosin containing resin acids such as abietic acid, parastolic acid, neoabietic acid, pimaric acid, isopimaric acid, and dehydroabietic acid as main components.
Wood rosin, tall oil rosin and the like can be mentioned. In the hydrogenation reaction of these rosin compounds, known hydrogenation reaction conditions can be appropriately selected. For example, the rosin compound is heated in the presence of a hydrogenation catalyst under a hydrogen pressure of usually about 1 to 20 MPa, preferably 5 to 15 MPa. As a hydrogenation catalyst, palladium-based, rhodium-based, platinum-based supported catalyst, nickel, metal powder such as platinum,
Various known compounds such as iodide and iodide such as iron iodide can be exemplified. In particular, rhodium carbon as a rhodium-based catalyst,
Palladium carbon is preferable as the palladium catalyst, and platinum carbon is preferable as the platinum catalyst. The amount of the catalyst used is
It is usually about 0.01 to 5% by weight, preferably 0.01 to 1% by weight, based on the rosin compound, and the reaction temperature is 100%.
The temperature is about 300 to 300C, preferably 150 to 290C.

[0013] The hydrogenated rosin obtained by the above method is purified, and a high molecular weight substance which is considered to have originated from the peroxide contained in the hydrogenated rosin, and the unsaturated rosin originally contained in the raw rosin compound. By removing the chloride, purified hydrogenated rosin is obtained. Various known purification methods can be appropriately selected for the purification, and specific examples thereof include operations such as distillation, recrystallization, and extraction. Industrially, purification by distillation is preferable. In the case of distillation, the temperature is usually about 200 to 300 ° C. and the pressure is 1
It is appropriately selected from the range of about 00 to 1500 Pa in consideration of the distillation time. In the case of recrystallization, for example, unpurified hydrogenated 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. Examples of good solvents include aromatic hydrocarbon solvents such as benzene, toluene and xylene; chlorinated hydrocarbon solvents such as chloroform; lower alcohols; ketones such as acetone; and acetates such as ethyl acetate. Is n-hexane, n-heptane, cyclohexane, isooctane and the like. In the case of extraction, unrefined hydrogenated rosin is converted to an aqueous alkali solution using alkaline water, and insoluble unsaponifiable substances contained in the rosin are extracted using an organic solvent, and then purified by neutralizing the aqueous layer. Hydrogenated rosin can be obtained.

The desired colorless rosin ester having excellent color tone and stability is obtained by converting an esterified product obtained by using the purified hydrogenated rosin and an alcohol to hydrogen under the pressure and heating of hydrogen in the presence of a hydrogenation catalyst. It can be obtained by a chemical reaction.

Specific examples of the alcohol 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; , Trimethylolethane, trimethylolpropane, cyclohexanedimethanol, etc.
Valent alcohols: tetrahydric alcohols such as pentaerythritol and diglycerin, etc., and any one or two or more of these alcohols can be used.

A known method can be used for the esterification reaction.
Specifically, under a high temperature condition of about 150 to 300 ° C.,
This is performed while removing generated water out of the system. The reaction is carried out under an inert gas such as nitrogen or helium, because if the air is mixed during the esterification reaction, the esterified product may be colored. The reaction does not necessarily require an esterification catalyst, but in order to shorten the reaction time, acetic acid, an acid catalyst such as paratoluenesulfonic acid, a hydroxide of an alkali metal such as calcium hydroxide, calcium oxide,
Metal oxides such as magnesium oxide can also be used.

By subjecting the esterified product obtained by the esterification reaction to a hydrogenation reaction under hydrogen pressure, a colorless rosin ester having a desired color tone and excellent stability can be obtained. Among the reaction conditions, the hydrogen pressure may be 1 MPa or more, but as a practical matter, the hydrogenation reaction at 20 MPa or more involves danger in production. Therefore, considering safety, the hydrogen pressure is preferably 1 MPa to 20 MPa. ,
Particularly preferably, 5 MPa to 15 MPa is desirable. 1M
Under a hydrogen pressure of less than Pa, hydrogenation and dehydrogenation of the esterified product occur simultaneously, and the stability of the resulting rosin ester tends to be slightly inferior. The hydrogenation reaction temperature is 1
The temperature is about 00 to 300 ° C, preferably 150 to 290 ° C. Examples of the hydrogenation catalyst used in the hydrogenation reaction include various known catalysts such as known palladium-based catalysts, rhodium-based catalysts, supported catalysts such as platinum-based catalysts, metal powders such as nickel and platinum, and iodides such as iodine and iron iodide. May be exemplified. Rhodium-based catalysts, palladium-based catalysts, and platinum-based catalysts are preferred to obtain colorless rosin esters having excellent color tone and stability, particularly rhodium-based catalysts such as rhodium carbon, palladium-based catalysts such as palladium carbon, and platinum-based catalysts such as platinum-based catalysts. It is preferable to use carbon. Rosin esters obtained by using other known hydrogenation catalysts such as nickel, platinum and other metal powders, iodine and iodide such as iron iodide during the hydrogenation reaction include rhodium-based catalysts, palladium-based catalysts, and platinum-based catalysts. The color tone and stability tend to be slightly inferior to rosin esters obtained using a catalyst. For example, when nickel, which is a metal powder, is used for the hydrogenation catalyst, the rosin ester of the product tends to be colored by a by-product generated by the reaction of nickel and unreacted carboxyl residues contained in the rosin ester. The amount of the catalyst used is
It is usually about 0.01 to 5% by weight, preferably 0.01 to 1% by weight, based on the esterification product. In the hydrogenation reaction, alicyclic hydrocarbons such as cyclohexane and decalin and aromatic hydrocarbons such as toluene and xylene can be appropriately used as a solvent.

The resin acid composition of the colorless rosin ester obtained by the production method of the present invention slightly varies depending on the pressure during the hydrogenation reaction, but is usually less than 1% of abietic acid and a tetrahydro compound (tetrahydroabietic acid and tetrahydropimar). (Acid mixture) 40 to 97% by weight, dihydro form (dihydroabietic acid and dihydropimaric acid mixture) 0 to 30% by weight, and dehydroabietic acid 3 to 20% by weight. The peroxide value is usually 1 or less.

According to the production method of the present invention, an extremely light-colored rosin ester having essentially the Hazen color tone (JIS K 0071-1) can be obtained. However, if necessary, an antioxidant can be obtained in each production step of the present invention. For example, various known organic phosphorus compounds and the like can be added as a coloring inhibitor.

[0020]

According to the production method of the present invention, the use of a stabilizer such as an antioxidant or a coloring inhibitor does not require any stabilizer, and the color tone, stability, odor, etc. can be compared with those of a conventionally known rosin ester. Can provide a colorless rosin ester in which various properties of the above have been significantly improved. The rosin ester is a tackifier for a pressure-sensitive adhesive or a hot melt adhesive, a modifier for rubbers and various plastics, a binder resin for traffic paint, a chewing gum base material, a modifier for ink and paint, a polyolefin film. And a dispersant for various additives for polyolefin films, and can improve the commercial value of the final product in these applications.

[0021]

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. In Examples,% indicates% by weight.

Example 1 (1) Hydrogenation reaction (production of hydrogenated rosin) An acid value of 171 and a softening point of 76 were added to a 3-liter autoclave.
℃, Gardner color tone (JIS K 0071-2) 6 unrefined Chinese gum rosin 1000g and hydrogenation catalyst 5
% Palladium carbon (water content 50%) 2g,
After oxygen in the system was removed, the system was pressurized to 10 MPa with hydrogen, heated to 260 ° C. with stirring, hydrogenated at the same temperature for 3 hours, acid value 167, softening point 74 ° C. A hydrogenated rosin having Gardner color tone 5 was obtained. (2) Purification (Production of Purified Hydrogenated Rosin) The unpurified hydrogenated rosin was distilled under a reduced pressure of 400 Pa under a nitrogen seal to obtain a general product having an acid value of 175.2, a softening point of 83 ° C., and a Gardner color tone of 2-3. The main fraction shown in Table 1 having a number was defined as purified hydrogenated rosin.

[0023]

[Table 1]

(3) Esterification The acid value obtained in the above (2) is 175.2, the softening point is 83 ° C.,
500 g of purified hydrogenated rosin having Gardner color tone 2 was placed in a 1-liter flask, heated to 180 ° C. under a nitrogen seal, added with 58 g of glycerin at 200 ° C. under melting and stirring, and then heated to 270 ° C. For 12 hours to obtain a purified hydrogenated rosin ester having an acid value of 7.0, a softening point of 95 ° C. and a Gardner color tone of 3.

(4) Hydrogenation reaction The purified hydrogenated 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 10 MPa with hydrogen and heated to 270 ° C.
A hydrogenation reaction is carried out at the same temperature for 3 hours, acid value 8.5, softening point 96 ° C, Gardner color tone 1 or less (Hazen color tone 30)
A colorless rosin ester was obtained.

Example 2 500 g of the purified hydrogenated rosin obtained in (1) of Example 1
Place in a liter flask, raise the temperature to 180 ° C. under a nitrogen seal, add 43 g of glycerin and 33 g of diethylene glycol at 200 ° C. under melt stirring, 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 Gardner color tone of 3 was obtained. Then, 200 g of the purified hydrogenated rosin ester was subjected to a hydrogenation reaction in the same manner as in (4) of Example 1 to obtain a colorless rosin having an acid value of 7.6, a softening point of 74 ° C. and a Gardner color tone of 1 or less (Hazen color tone of 40). The ester was obtained.

Example 3 500 g of the purified hydrogenated rosin obtained in Example 1 (2) was
The mixture was placed in a liter flask, heated to 180 ° C. under a nitrogen blanket, added with 5 g of glycerin and 67 g of pentaerythritol at 200 ° C. under melting and stirring, then heated to 280 ° C., and subjected to an esterification reaction at the same temperature for 18 hours. The reaction was performed to obtain a purified hydrogenated rosin ester having an acid value of 17.2, a softening point of 92.0 ° C., and a Gardner color tone of 8. Next, 200 g of the purified hydrogenated rosin ester was subjected to a hydrogenation reaction in the same manner as in Example 1, (4) to obtain an acid value of 19.8 and a softening point of 91.5.
A colorless rosin ester having a Gardner color tone of 1 ° C. or less (Hazen color tone of 60) was obtained.

Comparative Example 1 Example 1 was repeated except that 500 g of unpurified hydrogenated rosin obtained in (1) of Example 1 was used as a starting material for rosin ester.
In the same manner as (3), an unpurified hydrogenated rosin ester having an acid value of 4.5, a softening point of 93 ° C. and a color tone of Gardner 8 was obtained.
Next, 200 g of the unpurified hydrogenated rosin ester was subjected to a hydrogenation reaction in the same manner as in Example 1, (4), and the acid value was 8.
5. A rosin ester having a softening point of 95 ° C. and a Gardner color tone of 6 was obtained.

Comparative Example 2 Example 3 was repeated except that 500 g of unpurified hydrogenated rosin obtained in (1) of Example 1 was used as a starting material for rosin ester.
In the same manner as in the above, a rosin ester having an acid value of 4.0, a softening point of 96 ° C. and a Gardner color tone of 7 was obtained.

Heat stability and weather resistance tests were conducted to compare color stability. The test method is as follows. The results are shown in Table 2. (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 allowed to stand in a circulating drier at 200 ° C. without a cover, and the color tone over time (gardner color number).
Was observed. Gardner color is JIS K007
1-2. (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 change in color tone (gardner color tone). The color tone was evaluated by using a 50% toluene solution. Gardner color is JIS K00
71-2.

[0031]

[Table 2]

Claims (3)

[Claims] 1. A process for producing a colorless rosin ester, comprising subjecting a purified hydrogenated rosin to an alcohol and subjecting the esterified product to a hydrogenation reaction in the presence of a hydrogenation catalyst. 2. In the hydrogenation reaction of the esterified product,
The method according to claim 1, wherein the reaction pressure is 1 MPa or more. 3. The hydrogenation reaction of the esterified product,
3. The process according to claim 1, wherein the hydrogenation catalyst is a palladium-based, rhodium-based or platinum-based catalyst.