JPH02391B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to a novel method for preparing pentaerythritol esters of rosin. In particular, the present invention is characterized by reducing the reaction time for the production of rosin/pentaerythritol ester by reacting rosin and pentaerythritol in the presence of trace amounts of phosphinic acid (H ₃ PO ₂ ) as a catalyst. The aim is to shorten the Esterification of tall oil rosin also improves the color properties of the resulting rosin/pentaerythritol. Description of the Prior Art Rosin is a monocarboxylic acid mixture having primarily 20 carbon atoms (C ₂₀ ) fused rings. This monocarboxylic acid is typified by levopimaric acid and abietic acid, which form various substituents. The rosins used in this invention are gummy rosin, udon rosin and tall oil rosin. The hydrophilic component contained in the liquid part from tree sap and the cambium layer of the tree becomes a hydrophobic solid component through natural separation or conversion, and in general, various rubbers are A substance, resin and wax are formed. The oleoresin intermediate used in this method is made from southern yellow pine (southern yellow pine) grown in the southeastern United States, France, etc.
This is typified by the pine rubber that flows out from the cut end of the trunk of the pine tree. Pine gum contains about 80% (rubbery) rosin and about 20% turpentine. Resinization from oleo resin occurs by natural evaporation of oil from the extrudate or slow collection in white and red wood in ducts. The trunks of Pinus spp. are useful after being cut into chips, extracted with hexane or high-boiling paraffin, and then fractionated to produce turpentine, turpentine oil, and turpentine compounds. In the Kraft process, sulfate pulping in papermaking, pine is digested with alkali to produce crude tall oil and crude turpentine sulfates as by-products. Fractional distillation of crude tall oil produces tall oil rosin and fatty acids. The chemical transformation of gummy rosin, udon rosin and tall oil rosin is esterification in the method of this invention. Since the products obtained by esterification of rosin have been found to have useful properties, a number of esterification processes have been developed, particularly those with polyhydric alcohols. U.S. Patent Nos. 2,369,125, 2,590,910 and
No. 2572086 discloses a method for esterifying rosin with glycerol and pentaerythritol in the presence of a polyhydric alcohol. In this case, the esterification is usually carried out prior to the disproportionation treatment of the rosin. As is well known, the disadvantage of esterifying tall oil rosin with pentaerythritol is that there are problems with color change compared to esterification with glycerol. When tall oil rosin with a Gardner color number of 8 is used as a starting material, the color number of the pentaerythritol ester is 13 to 18, while the color number of the glycerol ester is 8 to 9. In addition, the time required for ester formation is long, and tall oil rosin/
The formation time of glycerol ester is 10 to 12 hours, whereas the formation time of tall oil rosin/pentaerythritol ester under the same conditions is 30 to 48 hours. In US Pat. Nos. 3,780,012 and 3,780,013, pentaerythritol esters formed using tall oil rosin are shown to be significantly darker in color than when using gummy rosin or downy rosin. In US Pat. No. 3,780,012, the rosin is treated with paraformaldehyde and then distilled prior to esterification.
In US Pat. No. 3,780,013, a phenol sulfide compound is added during esterification.
The color of the product obtained by such a method is
It is M on the USDA scale (equivalent to 11 or 12 on the Gardner scale). Also, a 20% excess amount of pentaerythritol is used in this example. In US Pat. No. 2,729,660 it is shown that strong acids, etc. used as catalysts during esterification darken the color of the product. In this patent, 0.5% to 5% of aliphatic or aromatic esters of phosphorous acid are used as esterification catalysts for higher fatty acids, rosin acids, or mixtures thereof.
Added. In addition to preventing the color of the product from becoming dark during esterification, attention has also been paid to shortening the reaction time. An inherent disadvantage of this method is that during the esterification step, the alcohol used to form the phosphite catalyst decomposes and produces a foul odor. U.S. Pat. No. 4,172,070 shortens the esterification time of tall oil rosin with pentaerythritol and improves its oxygen stability by using allylsulfonic acid in place of conventional esterification catalysts such as calcium oxide. A method for producing rosin esters of superior quality and improved color and softening point is disclosed. However, since this method uses a large amount of pentaerythritol (35% excess), the acid value is significantly reduced. The ring and ball softening point of this product is 77°C to 86.5°C. Note that the softening point of commercially available pentaerythritol ester is 95°C to 105°C. OBJECT OF THE INVENTION The object of this invention is to provide a new method for the preparation of pentaerythritol ester of rosin. Another object of this invention is to use a catalyst to accelerate the rosin/pentaerythritol reaction and shorten the reaction time. Another object of the invention is to reduce the amount of pentaerythritol used, lower manufacturing costs and increase the softening point (preferably 95°C or lower).
105℃). Yet another object of this invention is to provide a method for preparing pentaerythritol esters having a color comparable to that of glycerol esters of tall oil rosin. SUMMARY OF THE INVENTION It has been found that when phosphinic acid (also called hypophosphorous acid) is used as a catalyst, it works effectively even in trace amounts to promote the reaction between rosin and pentaerythritol. In particular, when tall oil rosin is reacted with at least an equal amount of pentaerythritol, adding 0.05% to 0.5% phosphinic acid by weight to rosin and reacting at a reaction temperature of about 180° C. to about 300° C. The Gardner color number of the tall oil rosin ester produced is only 0 to 2 higher than the Gardner color number of the raw material rosin. DESCRIPTION OF EXAMPLES Phosphinic acid is a strong cyclic agent and is used in light-colored fatty acids (U.S. Pat. No. 3,232,968), carboxylic acid esters with poly(oxyalkylene) compounds (U.S. Pat. No. 979,673 and U.S. Pat. No. 3,071,604), and glycols. as an antioxidant or decolorizer in the preparation of acrylic and methacrylic esters (Japanese Patent No. 7311084) or light-colored alkyl resins (Japanese Patent No. 12997). Phosphinic acid is also used as a treatment agent for tall oil. In this case, the impurities and color bodies contained in tall oil are converted into non-distillable compounds by the phosphinic acid, and the decarboxylation of the rosin acids contained therein is promoted (US Pat. No. 2,441,197). ). In the novel rosin esterification process currently in use, a very small amount of phosphinic acid is used as the sole esterification catalyst. The rubbery rosin, oil rosin, and tall oil rosin that are the targets of the method of this invention may be subjected to another treatment prior to esterification. For example, in addition to the distillation treatment performed in the fractional extraction method, disproportionation, hydrogenation, polymerization, or a combination of these treatments can be performed. Generally, esterification of rosin involves the introduction of rosin into a reaction vessel, up to 18% excess pentaerythritol and 0.01% excess pentaerythritol by weight relative to the rosin.
% to 0.5% of phosphinic acid. The reaction temperature is about 180℃ to 300℃
℃, but the desired temperature is about 250℃ to 280℃
It is ℃. The reaction time is about 25 hours or until the acid value of the rosin becomes about 15 or less. The preferred amount of phosphinic acid added as a catalyst is about 0.1% to about 0.25% by weight relative to the rosin;
Addition of 0.5% or more of this phosphinic acid has no effect. The esterification reaction is preferably carried out in an inert atmosphere. This can be accomplished by venting the nitrogen in the reaction vessel before adding the reactants and introducing nitrogen during the reaction. A characteristic of rosin ester is that it is pale in color, but its color is easily affected by oxygen gas, so it is necessary to avoid contact with oxygen as much as possible. Also, the advantage of phosphinic acid catalysts is that the discoloration effect during the esterification reaction is small. Therefore, the color of the rosin ester does not differ much from the color of the rosin used as a raw material. When tall oil rosin is esterified, the color of the resulting ester becomes darker due to the action of the catalyst used in the method of this invention, but the extent of this darkening is only slightly to 0
or 2. Therefore, when tall oil rosin with a Gardner color number of 5 is used as a raw material, the Gardner color number of the produced ester is 5 to 7,
If tall oil rosin with a Gardner color number of 10 is used, the Gardner color number of the ester produced will be 10 or more.
It is 12. In a preferred embodiment of the method of this invention,
Rosin, which is a starting material, is placed in a reaction vessel,
After exposure to an inert atmosphere, 0.2% phosphinic acid (50% aqueous solution in terms of active phosphinic acid) and 15% to 18% excess pentaerythritol are added by weight to the rosin. 275 mixture
After heating to ℃, slowly spray with an inert gas such as nitrogen. Note that this temperature is the total reaction time (18
hours to 24 hours). After about 18 to 20 hours have elapsed from the start of the reaction, the inert gas atomization is switched to the steam atomization, and solid sodium hydroxide is added in an amount of about 0.053% by weight based on the rosin to neutralize the phosphinic acid catalyst. The resulting mixture is further cooled. (Note that a 50% aqueous solution of sodium hydroxide may be used, but in that case it must be added prior to steam atomization.) In a more preferred embodiment, the rosin used is tall oil. Rosin,
Upon cooling, the Gardner color number change of the final product relative to the raw rosin is 0 to 2, and its Ball and Ring softening point is approximately 95.
℃ to about 105℃. The examples now show that rosin-pentaerythritol esters prepared by the method of the present invention exhibit unexpected color change properties.
Furthermore, it can be seen that the required reaction time is also short.
In the following examples, unless otherwise specified, ratios are expressed by weight. Example 1 Into a suitable reaction vessel are charged 100 parts of Gardner color number 10 tall oil rosin, 115 parts of pentaerythritol, and 0.2 parts of 50% active phosphinic acid aqueous solution. The mixture thus obtained was heated to 250℃ to 260℃.
When heated to and held for 20 hours, an ester with an acid value of 13, a ring and ball softening point of 97°C, and a Gardner color number of 11 is obtained. Example 2 Using tall oil rosin with Gardner color number 5,
When the other conditions are the same as in Example 1 and the reaction is carried out,
Acid value 15, softening point 96℃, and Gardner color number 6+
of ester is obtained. Example 3 When the reaction was carried out under the same conditions as Example 1 without adding phosphinic acid, it took 45 hours to reach an acid value of 12, and the final Gardner color number was 18+.
It is. As can be seen by comparing the first and second examples, the reaction in this example demonstrates that phosphinic acid has catalytic activity. Example 4 Into a suitable reaction vessel, 100 parts of tall oil rosin with a Gardner color number of 6 and 12.3 parts of pentaerythritol were charged, and in place of phosphinic acid, 100% active calcium hydroxide (U.S. Pat. No. 3780013) is added in an amount of 0.1% by weight. The mixture thus obtained is heated to 270°C and held for 24 hours, yielding an ester with an acid number of 5, a ring and ball softening point of 102°C and a Gardner color number of 13. As can be seen by comparing the first and second examples, this example demonstrates that the catalytic effect of phosphinic acid is superior to common esterification catalysts. Example 5 When the reaction is carried out without using a catalyst and under the same conditions as in Example 4, an ester having an acid value of 10, a softening point of 99°C and a Gardner color number of 12 is obtained. In this case, the required holding time at the reaction temperature is
It is 24 hours. Example 6 In an esterification reaction plant of suitable scale, 100 parts of Gardner color number 7+ tall oil rosin,
Charge 12.2 parts of pentaerythritol and 0.2 parts of 50% active phosphinic acid aqueous solution. this mixture
When heated to 280℃ and held for 17.5 hours, the acid value is 8.9,
An ester with a ring and ball softening point of 96° C. and a Gardner color number of 8 is obtained. Example 7 Into a suitable reaction vessel are charged 100 parts of a commercially available partially hydrogenated uddrodine (Gardner color number 5+), 12.3 parts of pentaerythritol and 0.2 parts of a 50% active phosphinic acid aqueous solution. When this mixture is heated to 270°C and held at that temperature for 17.5 hours, the acid value
14, an ester with a ring and ball softening point of 94°C and a Gardner color number of 6.5 is obtained. Example 8 When a hydrogenated tall oil rosin with a Gardner color number of 4+ was used and the other conditions were the same as in Example 7, an ester with an acid value of 14, a softening point of 93°C, and a Gardner color number of 8+ was obtained. It will be done. In this case, the required holding time at the reaction temperature is 17.5 hours. Example 9 When a disproportionated tall oil rosin with a Gardner color number of 4+ was used and the upper temperature limit was 250°C, and the other conditions were the same as in Example 7, the acid value was
12, an ester with a softening point of 90°C and a Gardner color number of 6.5 is obtained. In this case, the required holding time at the reaction temperature is 39 hours. Example 10 Into a suitable reaction vessel are charged 100 parts of gummy rosin of Gardner color number 10, 11.5 parts of pentaerythritol, and 0.2 parts of 50% active phosphinic acid aqueous solution. When this mixture is heated to 270°C and held for 16 hours, it has an acid number of 12 and a ring and ball softening point of 102.5.
C. and a Gardner color number of 8 is obtained. Example 11 Using the method of this invention, pentaerythritol esters are obtained from disproportionated and distilled tall oil rosin samples. One rosin sample is
After distillation and before cooling (while the sample was hot), 0.2% of phosphinic acid catalyst was added, and this was stirred at 177°C for 30 minutes before cooling. Note that the Gardner color number of both samples is 2-. The results are shown in the table.

Table: Esters prepared from rosin pre-containing 0.2% catalyst are generally inferior in color to esters prepared with subsequent addition of catalyst.
Even if 0.3% catalyst is added later, the product is darker. Examples 7, 8, 9, 10, and 11 demonstrate the catalytic activity of phosphinic acid for the esterification of rosins other than tall oil rosins and pretreated rosins. Although the present invention has been described above based on various embodiments, the present invention is not limited to the above embodiments, and can be implemented with various modifications by those skilled in the art.

Claims (1)

[Claims] 1. A method for esterifying rosin with at least an equal amount of pentaerythritol, characterized in that the esterification reaction is carried out by heating the rosin and pentaerythritol in the presence of a phosphinic acid catalyst. A method for esterifying rosin. 2. The phosphinic acid is contained in an amount of 0.01% to 0.5%, the reaction is carried out in an inert atmosphere, and the reaction temperature and reaction time are respectively controlled.
The reaction time is 180°C to 300°C and 18 to 20 hours, and after the reaction is completed, steam is sprayed and sodium hydroxide is added in an amount capable of neutralizing the phosphinic acid. The method for esterifying rosin according to item 1. 3 The rosin is 15% at 250℃ to 280℃
The method for esterifying rosin according to claim 1, wherein the esterification is carried out using pentaerythritol in an excess of 18% to 18%. 4. The method for esterifying rosin according to any one of claims 1, 2, and 3, wherein the rosin is tall oil rosin, rubbery rosin, or oil rosin. 5. The method for esterifying rosin according to claim 4, wherein the rosin is a disproportionated rosin, a hydrogenated rosin, or a polymerized rosin. 6. Claims characterized in that the Gardner color number of the tall oil rosin ester is 0 to 2 larger than the Gardner color number of the tall oil rosin, and the ball and ring softening points of the ester are 95°C to 105°C. The method for esterifying rosin according to item 4. 7. In the method for esterifying rosin with pentaerythritol, the esterification reaction is carried out in an inert atmosphere in the presence of 0.01% to 0.5% liphosphinic acid in weight ratio to rosin, and the reaction temperature and reaction time are each about 180°C. or about
A process for esterifying rosin at 300°C and for a maximum of 20 hours, characterized in that the phosphinic acid is neutralized with sodium hydroxide. 8. The rosin is esterified with a 15% to 18% excess of pentaerythritol in the presence of 0.1% to 0.25% phosphinic acid, and the reaction is carried out under atomization of an inert gas. A method for esterifying rosin according to claim 7. 9. The rosin esterification method according to claim 7, wherein the esterification reaction is carried out at 250°C to 280°C. 10. The rosin esterification method according to claim 7, wherein the gas constituting the inert atmosphere is nitrogen gas. 11. The method for esterifying rosin according to claim 7, 8, or 9, wherein the rosin is tall oil rosin, rubbery rosin, or downy rosin. 12. The rosin esterification method according to claim 10, wherein the rosin is a disproportionated rosin, a hydrogenated rosin, or a polymerized rosin. 13 Claims characterized in that the Gardner color number of the tall oil rosin ester is 0 to 2 larger than the Gardner color number of the tall oil rosin, and the ball and ring softening points of the ester are 95°C to 105°C. The method for esterifying rosin according to item 11. 14 A method for esterifying tall oil rosin, in a temperature range of 180°C to 300°C, in a weight ratio of 0.01% to 0.5 to the tall oil rosin.
% of phosphinic acid, the tall oil rosin has the highest weight ratio to the equivalent weight of the rosin.
The Gardner color number of the tall oil rosin/pentaerythritol ester produced by reacting with 18% excess amount of pentaerythritol is 0 to 2 larger than the Gardner color number of the tall oil rosin, and the ball and ring softening points of the ester are 95°C. A method for esterifying tall oil rosin, characterized in that the temperature is between 105°C and 105°C. 15 Phosphinic acid present between 0.1% and 0.25%
%, and the reaction proceeds under spraying of an inert gas. 15. The method for esterifying tall oil rosin according to claim 14. 16. The method for esterifying tall oil rosin according to claim 14, wherein the reaction temperature is 250°C to 280°C.