JPS59230072A - Preparation of light-colored rosin ester having improved stability - Google Patents

Abstract

PURPOSE:To obtain a light-colored rosin ester having improved stability to oxidation and coloring by heating only two processes of distillation purification process of rosin and esterification process, by adding a specific organic sulfur compound to an esterification system. CONSTITUTION:In esterifying distilled and purified rosin with an alcohol, preferably 0.1-1wt% purified organic sulfur compound [e.g., 4,4'-bis(phenol)sulfide, 1,1'-bus(beta-naphthol)sulfide, etc.)] shown by the formula (A substituted aromatic ring; R is H, 1-20C alkyl, or cycloalkyl; n is 1-3; m is 1-4; X is 1-2; Y is 0- 2; P is 0-4) based on the purified rosin is added to the esterification system. USE:Useful as a raw material for adhesive, pressure-sensitive adhesive, resin for ink, traffic coating compound, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a rosin ester that is light in color and has good stability.

Rosin esters are one of a group of resins called hard resins, and are widely used as raw materials for industrial adhesives, pressure-sensitive adhesives, ink resins, traffic paints, heat-sealable plastics, etc. The esterified products of rosin are colored yellow or yellowish brown, and have poor heat resistance and aging resistance. Therefore, it is desired to develop a rosin ester with good stability.

As a rosin ester that satisfies such requirements, rosin esters are known, which are obtained by esterifying disproportionated rosin or hydrogenated rosin; Therefore, it cannot be said that the above requirements are fully satisfied in terms of not only coloring during the esterification reaction but also stability against oxidation and heat coloring.

Special Publication No. 45-33771 and Special Publication No. 49-205
Publication No. 99 describes a method of disproportionating rosin or a rosin compound with a specific organic sulfur compound. Although the color was lighter than that of the conventional rosin ester and an improvement effect could be recognized, it was still colored yellow and the coloring was severe due to heating, and the improvement in coloring stability as a rosin ester was not satisfactory.

Furthermore, JP-A No. 55-9605 discloses a method for producing stable ioirodine ester, in which high levels of rosin, which are thought to have arisen from peroxides contained in the raw material rosin, are produced by distilling disproportionated rosin. A method is described in which, after removing molecular weight substances, unsaponifiable substances originally present in the raw material rosin, and unsaponifiable substances generated during the disproportionation reaction, this distilled and purified disproportionated rosin is esterified with alcohol. However, even with this method, a coloring phenomenon occurs during the esterification reaction, and the resulting rosin ester has unsatisfactory stability against oxidation and heat coloring.

Furthermore, this method has disadvantages in terms of economics since it requires three steps: a disproportionation reaction step, a distillation step, and an esterification reaction step.

Therefore, the present inventors discovered that the coloration of rosin ester is largely caused by the high molecular weight substances contained in the rosin, but even if the high molecular weight substances are removed by distillation purification, the heated coloring components cannot be completely removed. Therefore, the fact that it is colored during the esterification reaction,
The poor aging resistance of rosin esters is due to the resin acids with abietic acid-type conjugated double bonds and the high molecular weight substances in rosin, and the fact that the disproportionation reaction and esterification reaction of rosin proceed at approximately the same temperature. As a result of various studies, we found that by allowing a specific organic sulfur compound to coexist in the esterification reaction system, a light color can be obtained with only two steps, the rosin distillation purification step and the esterification reaction step. Furthermore, the present invention was completed by successfully obtaining a rosin ester with excellent stability against oxidation and heat coloring.

That is, the present invention is characterized in that distilled purified rosin is esterified with alcohol, and one or more compounds selected from the group of compounds represented by the following general formula are allowed to coexist in the esterification reaction system. It is something.

In the general formula, A is a substituted aromatic ring such as a benzene ring or a naphthalene ring, R is hydrogen, or an alkyl group or cycloalkyl group of 01 to 020, n is an integer of 1 to 3, and m is an integer of 1 to 3. An integer of 4 or an integer of 1 to 2, Y is an integer of 0 to 2, p is an integer of 0 to 2, and p is an integer of 0 to 2.
Indicates an integer of 4.

The distilled and purified rosin used in the present invention includes abietic acid, parastric acid, neoabiedic acid, pimaric acid,
Refers to distillates of gum rosin, wood rosin, and tall rosin whose main components are resin acids such as isobimaric acid and dehydroabietic acid. Distillation is usually carried out at a pressure of 50 mmHg or less and an internal temperature of 200 to 300 °C, and vacuum simple distillation is used. ,
Methods such as vacuum steam distillation and thin film vacuum distillation are used.
Under normal distillation conditions, 2-10% of high molecular weight substances are removed as pitch. When a rosin-ester with a high softening point is intended, it is preferable to also remove 2 to 10% of the initial fraction.

The alcohol used in the present invention includes monohydric alcohols such as m-octyl alcohol, 2-ethylhexyl alcohol, tepyl alcohol, lauryl alcohol, and stearyl alcohol, ethylene glycol,
Diethylene dalicol, polyethylene glycol, propylene glycol, dipropylene glycol, hollybrobylene dalicol, neopentyl glycol, etc.
Examples include trihydric alcohols such as glycerin and trimethylolpropanato; tetrahydric alcohols such as diglycerin; and hexahydric alcohols such as dipentaerythritol.

The esterification reaction in the present invention is carried out by a known method, that is, by distilling purified rosin and alcohol in the presence of an inert gas.
This can be carried out by heating at 150 to 300°C and removing reaction product water from the system. As a catalyst for the esterification reaction, acetic acid, nogradruenesulfonic acid, phosphoric acid,
Known catalysts such as lithium hydroxide, calcium hydroxide, magnesium oxide, zinc oxide, calcium acetate and the like are used.

Examples of compounds represented by the general formula used in the present invention include 4,4'-bis(phenol) sulfide 4,41-bis(phenol) sulfoxide 4,4'-bis(phenol) sulfone 4,41 -bis(7er/-l)thiol sulfinate 4, 41-bis(phenol)thiol sulfonate 2, 2'-bis(p-cresol) sulfide 2, 21-bis(p-cresol) sulfoxide 2, 2,21-bis(p-cresol)sulfone 2,21-bis(para-tert-butylphenol) sulfide 2,21-bis(para-tert-butylphenol) sulfoxide 2,21-bis(para-tert-butylphenol)
tert-butylphenol) sulfone 4,4'-
Bis(6-tert-butylmetacresol) sulfide 4,41-bis(6-tert-butylmetacresol) sulfoxide 4,41-bis(rotardibutylmetacresol) sulfone 4,4'-bis(6-tert- butyl orthocresol) sulfide 4,41-bis(6-tert.butyl orthocresol) sulfoxide 4,4'-bis(6-tert.butyl orthocresol) sulfone 4,4'-
Bis(resorcinol) sulfide 4,41-bis(resorcinol) sulfoxide 4,41-bis(resorcinol) sulfone l,11-bis(β-naphthol) sulfide 1,l bis(β-naphthol) sulfoxide 1,1'-his (β-naphthol) sulfone 4
, 4'-bis(α-naphthol) sulfite 4,4'-
Bis(α-naphthol) sulfoxide 4,4'-His(α-naphthol) sulfone 5,51-bis(pyrogallol) sulfide 5,5+-bis(pyrogallol) sulfoxide 5,5'-bis(pyrogallol) sulfone baracrene Among them, compounds having a sterically hindered hydroxyl group bonded to a benzene ring are preferred, and organic sulfur compounds such as sulfide is preferred. Hereinafter, these organic sulfur compounds will be referred to as lightening agents.

The above-mentioned lightening agent may be added in an amount of 0.01 to 5wt% based on the distilled and purified rosin, but from the viewpoint of lightening effect and economic efficiency, addition of 0.1 to 1wt% is particularly preferable. .

The reason why a lightening agent is allowed to coexist in the esterification reaction system is due to the fact that the disproportionation reaction and esterification reaction of rosin proceed at almost the same temperature. This is because the rosin disproportionation reaction is also to proceed. However, if a lightening agent is added at the end of the esterification reaction, the effect of improving the color tone and thermal stability of the resulting rosin ester may not be as good as expected. It is preferable to add

The rosin ester obtained by the method of the present invention has extremely low color strength compared to conventional rosin esters and is stable against oxidation and heat coloring, so it can be used for pressure sensitive adhesives, hot melt adhesives, and inks. It is suitably used as a raw material for resins, traffic paints, sealing materials, heat-sealable plastics, etc.

The rosin ester has even higher stability (if required, a phenolic antioxidant or a phosphite stabilizer may be used in combination).

Hereinafter, the present invention will be explained in more detail based on Examples.

(A) Rosin Distillation Purification Examples 1 to 3 In Examples 1 and 2, Chinese gum rosin (oxidized 1
65), and in Example 3, tall oil rosin (168 oxidation) was charged at 12,009 m each, and 200 m
Heat to 120°C after completely melting the rosin.
The system was then evacuated to a pressure of 3 kg Hg, and the temperature inside the flask was raised from 120'C to 2 ao'C to obtain the fractions shown in Table 1.

Table 1 Rosin distillation data C) was obtained.

■) Rosin ester production Examples 4 to 6 The main distillate obtained in Example 1 was placed as rosin in a glass reaction vessel (200 cc volume) equipped with a stirrer, a water drain pipe (with a cooler), a thermometer, and a nitrogen suction pipe. 1007, glycerin 11.69 as the alcohol, and 4,4 in Example 4 as the lightening agent.
1-bis(6-tert-butyl-m-cresol)
The sulfide was 0.37, and in Example 5, 4,4"-bis(
In Example 6, 4,41-bis(6-tert-butyl-m-cresol) sulfone was added to 0.3% of 6-tert-butyl-m-cresol) sulfoxide.
3 g was charged and reacted for 8 hours with stirring at 270° C. under a nitrogen atmosphere to obtain rosin esters having the constant values shown in Table 2.

Examples 7 to 9 In Example 7, 4,4'-bis(phenol) sulfoxide was used as a lightening agent. 7. In Example 8, o...
59, 1.09 was used in Example 9, and rosin esters with constant numbers shown in Table 2 were reacted in the same manner as in Example 4, except that 0.19 of lithium hydroxide monohydrate was used as the esterification reaction catalyst. I got it.

Example 10 The reaction was carried out in the same manner as in Example 4, except that 1.07% of 1,1'-bis(β-naphthol) sulfide was used as the lightening agent, to obtain rosin esters having the constant numbers shown in Table 2.

Examples 11-12 In Example 11, dodecyl alcohol r was used as the alcohol.
yo, 69, in Example 12, pentaerythritol 1
3. The reaction was carried out in the same manner as in Example 5, except that Z.
Rosin esters having the constant numbers shown in Table 2 were obtained.

Examples 13-14 Example 13 is an example of a distilled purified rosin.

In Example 14, 100 g of the main distillate obtained in Example 3 and 13.7 g of pentaerythritol were used as the alcohol.
0g, 14g of pentaerythritol as alcohol
- Reacted in the same manner as in Example 12 except that Table 2
A rosin ester with the constant shown in was obtained.

Examples 15-16 In Example 15, the lightening agent was added at 270° during the esterification reaction.
The reaction was carried out in the same manner as in Example 13, except that in Example 16, it was added 6 hours after the temperature was raised to 270 °C during the esterification reaction.
A rosin ester with the constant shown in was obtained.

Example 17 To ensure high stability against oxidation and heat coloring,
In particular, as stabilizers 2,5-ditertiary-amylhydride'quinone o, +17 and tridecylphosphite o.
The reaction was carried out in the same manner as in Example 13, except that 59 was added 8 hours after the start of the esterification reaction, to obtain rosin esters having the constant numbers shown in Table 2.

Comparative Example 1 A reaction was carried out in the same manner as in Example 5 except that no lightening agent was used to obtain rosin esters having the constant values shown in Table 2.

Comparative Example 2 A reaction was carried out in the same manner as in Example 5, except that undistilled gum rosin (gum rosin produced in China) was used as rosin, and rosin esters having the constant numbers shown in Table 2 were obtained.

Comparative Example 3 A reaction was carried out in the same manner as in Example 14, except that undistilled tall rosin (manufactured by Harima Kasei Kogyo Co., Ltd. - Thor WW-5) was used as rosin ester, and rosin esters having the constant numbers shown in Table 2 were obtained. Ta.

(0) Thermal stability test The rosin esters 3q obtained in Examples 4 to 17 and Comparative Examples 1 to 3 were placed in a colorimetric tube with an inner diameter of 10 mm and a length of 15 cm,
After heating and melting, the mixture was placed in a constant temperature oven at 180'C, and the color tone after 5 and 10 hours was measured using a Gardner colorimeter. The measurement results are shown in Table 2.

As is clear from Table 2, the rosin ester obtained by the method of the present invention is the rosin ester obtained by esterifying distilled purified rosin without using a lightening agent (Comparative Example 1), Although the rosin esters were made to coexist, the rosin esters were lighter in color and had better thermal coloring stability than the rosin esters obtained by esterifying undistilled rosin (Comparative Examples 2 and 3).

Table 2 The method of the present invention is as explained in detail above, and includes only two steps: distilling and refining the rosin, and esterifying the rosin (simultaneously disproportioning it).
This method is industrially much more economical than the method described in Japanese Patent Publication No. 55-9605, which requires three steps: a disproportionation reaction step, a distillation purification step, and an esterification step. In addition, two of the conventional disproportionation process and esterification process
Compared to a process-only method, the color tone and thermal stability of the resulting rosin ester are much better.

Claims (4)

[Claims] (1) It is characterized by esterifying the rosin produced by I-R ff with alcohol, and allowing one or more compounds selected from the group of compounds represented by the following general formula to coexist in the esterification reaction system. A method for producing a light-colored and stable rosin ester. General formula substituted aromatic ring, R represents hydrogen, or an alkyl group or cycloalkyl group of 01 to 02G, n is an integer of 1 to 3, m
is an integer of 1 to 4, or an integer of 1 to 2, Y is an integer of 0 to 2, and p is an integer of O-4. (2) The method for producing a light-colored and stable rosin ester according to claim 1, wherein the distilled-purified rosin is distilled-purified gum rosin. (3) Claim 1 in which Y in the general formula is O
A method for producing a light-colored and stable rosin ester as described in Section 1. (4) Claim 1 in which Y in the general formula is 1
A method for producing a light-colored and stable rosin ester as described in Section 1.