JPS6230170A - Production of liquid rosin ester - Google Patents

Abstract

PURPOSE:To obtain the titled resin having light color and high stability and useful as a liquid tackifier for e.g. a hot-melt adhesive, by reacting a rosin with an alcohol under heating in the presence of a specific alkali metal iodide and anthraquinone. CONSTITUTION:The objective ester can be produced by the dehydrative condensation reaction of a rosin and an alcohol (e.g. propyl alcohol) under heating in the presence of sodium iodide and/or potassium iodide and anthraquinone, usually in an inert gas stream. The equivalent ratio of OH of the alcohol to COOH of the rosin is preferably 0.6-1.4. The amount of the alkali metal iodide and anthraquinone is preferably 0.1-1wt% each based on the rosin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing a liquid rosin ester, and more particularly, to a method for producing a liquid rosin ester that is light in color and has excellent stability.

Conventional technology Rosin ester, which is obtained by esterifying rosin with monohydric or polyhydric alcohol, is a liquid resin that has been used as an additive and modifier for adhesives, paints, etc. ing. In particular, the above-mentioned liquid rosin ester is used as an important component of adhesives, that is, as a so-called liquid tackifier, because of its adhesive properties. In addition to the above-mentioned rosin ester, liquid tackifiers include, for example, liquid terpene resins, liquid petroleum resins, polybutene, liquid polyisoprene, etc., and process oils and the like are used as plasticizers. However, while liquid rosin ester is superior to the other liquid resins and process oils mentioned above in terms of adhesive properties, it is not necessarily satisfactory in terms of color tone and heat stability.

For the above reasons, there is a demand in the industry for the development of new liquid resins, especially liquid rosin esters, which have excellent adhesive properties, are pale in color, and have excellent stability.

It is also known that a liquid gin ester with improved heat stability can be obtained by disproportionating or hydrogenating rosin and then esterifying it. Coloring is observed, which is difficult to prevent, and the heat stability required for liquid tackifiers cannot be satisfied. Furthermore, JP-A-59-230072 discloses a technique for producing a light-colored and stable liquid rosin ester by esterifying distilled 10 gin with alcohol in the presence of a specific Ia sulfur compound. Disclosed. However, since such a method requires two steps, a distillation step and an esterification step, the production efficiency is low and it is disadvantageous from an economic standpoint.

Problems to be Solved by the Invention In view of the above-mentioned current situation, the present inventors aimed to develop a new liquid rosin ester that can simultaneously satisfy various conditions such as color tone, heat stability, and production efficiency. As a result of extensive research, especially focusing on the stabilizer that should be added during the esterification reaction, we found that when a specific alkali metal iodide and anthraquinone are used in combination, a liquid rosin ester that meets the above purpose. Based on this new knowledge, the present invention has found that a JJ construction technology is provided.
It was completed by

Means for Solving the Problems The present invention provides a method for heating rosin and alcohol in the presence of anthraquinone and at least one alkali metal iodide selected from sodium iodide and potassium iodide. This invention relates to a method for producing liquid rosin ester, which is characterized by its light color and good stability.

In the present invention, as the rosin, any of various conventionally well-known rosin substances can be used.

Examples include gum rosin containing resin acids such as abietic acid, parastric acid, neoabietic acid, bimaric acid, isobimaric acid, and dehydroabietic acid as a main component, as well as wood rosin and tall oil rosin. can.

In the present invention, the alcohols can be appropriately selected from monohydric alcohols and dihydric alcohols in consideration of the softening point of the resulting rosin ester. Specific examples include butyl alcohol, butyl alcohol, pentyl alcohol, °hexyl alcohol,
In addition to alcohols with 3 to 7 carbon atoms such as heptyl alcohol, monohydric alcohols such as octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, and lauryl alcohol, and dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol. can be exemplified.

Further, in the present invention, in addition to the above-mentioned monohydric alcohol and dihydric alcohol, polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol can also be used in combination.

It is important that the esterification reaction of the present invention is carried out in the presence of at least one alkali metal iodide selected from sodium iodide and potassium iodide and anthraquinone, and this is the only way to achieve the special characteristics unique to the present invention. A remarkable effect is produced.

The esterification reaction can be carried out in the same manner as known esterification reactions of this type, except for using the above-mentioned specific alkali metal iodide and anthraquinone. That is, it is usually carried out by charging rosin and alcohol in the presence of the above-mentioned specific alkali metal iodide and anthraquinone, and heating the mixture under an inert gas stream in the presence or absence of a solvent to cause dehydration condensation. The heating reaction conditions can be the same as those of this kind of esterification reaction which is conventionally known. Further, during the above esterification reaction, a conventional esterification catalyst may be used in consideration of the reaction time. Examples of solvents that can be used in the above reaction include benzene,
Preferred examples include aromatic solvents such as toluene and xylene, and examples of esterification catalysts include acid catalysts such as sulfuric acid, acetic acid and para-toluenesulfonic acid, alkaline earth metal hydroxides such as calcium hydroxide, Examples include metal oxides such as magnesium oxide and calcium oxide, and common esterification catalysts such as calcium carbonate and magnesium acetate.

In the above reaction, the charging ratio of rosin and alcohol is not particularly limited, and is appropriately determined in consideration of the type of rosin, its acid value, the softening point of the esterified product, etc.

Usually, it is preferable that the ratio of hydroxyl groups in the alcohol to carboxyl groups in the rosin ranges from about 0.6 to 1.4.

The amount of alkali metal iodide used in the method of the present invention is about 0.01 to 3.0°C% (hereinafter simply referred to as %) based on the rosin, preferably about 0.1 to 1.0%. It is best to choose from.

Also, the use of anthraquinone in combination with the alkali metal iodide is about 0.01 to 3.0% based on the rosin.
, preferably from about 0.1 to 1.0%. If either of the above two components is less than the above range, it will be difficult to fully exhibit the pale color effect, and conversely, there is no particular advantage if both components are used beyond the above range, and it is rather economically It will be disadvantageous. Note that the timing of addition of the alkali metal iodide and anthraquinone may affect the color tone and heating stability of the liquid rosin ester obtained, so they are usually added in advance before esterification or added at the beginning of the reaction. It is preferable to do so.

Through the above reaction, the desired liquid rosin ester can be easily obtained. The liquid rosin ester thus obtained has excellent adhesive properties and exhibits unexpected characteristics in terms of color tone, heat stability, etc. compared to conventionally known liquid rosin esters, and the reason is as follows. Although it is not clear, alkali metal iodides have activity as disproportionation catalysts, side reactions such as ring-opening reactions and demethylation tend to occur, and the softening point of the resulting rosin ester tends to decrease. This is thought to be due to the fact that anthraquinone has a decolorizing effect.

The liquid rosin ester obtained by the method of the present invention can be widely applied to conventionally known uses, and in particular has the above-mentioned properties, namely adhesive properties, light color, and good heat stability. It can be suitably used as a liquid tackifier that is a component of melt adhesives. It goes without saying that when preparing the secondary composition, general additives such as antioxidants, light stabilizers, oils, etc. can be used in combination, if necessary.

EXAMPLES Examples will be given below to explain the method of the present invention in more detail, but it goes without saying that the present invention is not limited thereto.

Example 1 Tall oil rosin (1! I value: 174.5
<According to ASTM D465-51, the same applies below), Softening point: 68.0°C (according to the ring and ball method, the same applies below), Color tone 20G (Gardner color, the same applies below)) 600 g, Diethylene glycol 909, Sodium iodide 0.9a and anthraquinone 1.8Q, and heated under a nitrogen stream for 23 hours.
After heating to 0°C and reacting at the same temperature for 5 hours,
The temperature was raised to 70°C, and the reaction was continued at the same temperature for 5 hours.

The yield and various constants of the liquid rosin ester thus obtained are not shown in Table 1.

Example 2 A reaction was carried out in the same manner as in Example 1 except that triethylene glycol was used instead of diethylene glycol to obtain a liquid rosin ester.

Table 1 shows the yield and various constants of the rosin ester obtained.

Example 3 In Example 1, gum rosin (acid + i! [i: 169.5, softening point near 8.0°C, color tone = 6G) was used in place of tall oil rosin, and the reaction was carried out in the same manner as in Example 1, resulting in a liquid A rosin ester was obtained.

Table 1 shows the yield and various constants of the rosin ester obtained.

Example 4 A reaction was carried out in the same manner as in Example 1 except that 260 g of n-octyl alcohol was used in place of 90 g of diethylene glycol to obtain a liquid rosin ester.

Table 1 shows the yield and various constants of the rosin ester obtained.

Comparative Example 1 A liquid rosin ester was obtained by carrying out the reaction in the same manner as in Example 1 except that sodium iodide was not used.

Table 1 shows the yield and various constants of the rosin ester obtained.

Comparative Example 2 In Example 1, the amount of sodium iodide used was 1.2
9 and except that anthraquinone was not used, the reaction was carried out in the same manner to obtain a liquid rosin ester.

Table 1 shows the yield and various constants of the rosin ester obtained.

The acid value of the liquid rosin ester obtained with each of the above,
Table 1 shows the results of examining the viscosity (25° C., centivoids), color tone, and heating stability. The heating stability was tested by the following method.

<Heating stability test> 5 g of each liquid rosin ester sample was
The mixture was placed in a test tube with a length of 15 cm and left in a circulating air dryer at 200° C., and the color tone of each content was measured after 2 and 6 hours using a Gardner colorimeter. The smaller the change between the measured initial color tone and the color tone after heating, the better the heating stability.

Table 1 (that's all)

Claims (2)

[Claims] (1) A light-colored and highly stable liquid that is produced by heat-reacting rosin and alcohol in the presence of anthraquinone and at least one alkali metal iodide selected from sodium iodide and potassium iodide. Method for producing rosin ester. (2) Approximately 0.0 of alkali metal iodide to rosin
1-3.0% by weight and about 0.01-3% anthraquinone
．． A method according to claim 1, in which 0% by weight is used.