JP2020176219A - Wax expansion agent and wax composition containing the same - Google Patents

Abstract

To provide a wax expansion agent capable of increasing the thermal expansion of wax by the addition of the agent in a small quantity, and having less influence on the melting point of wax.SOLUTION: A wax expansion agent, comprising: (A) a magnesium salt of a monovalent linear saturated fatty acid having 16-22 carbon atoms and (B) a monovalent linear saturated fatty acid having 16-22 carbon atoms, the mass ratio [(A): (B)] of the magnesium salt to the fatty acid being 10:90 to 60:40.SELECTED DRAWING: None

Description

The present invention relates to a wax swelling agent which can enhance the thermal expansion property by adding a small amount to the wax and has a small influence on the melting point of the wax, and a wax composition containing the same.

The wax is usually a waxy compound that melts at 50 to 90 ° C., and solid esters composed of higher fatty acids and higher monohydric alcohols, paraffin waxes that are hydrocarbons, and the like are widely used. Since wax exhibits water resistance, plasticity, glossiness, mold releasability, etc., it is used in various applications as an additive for the purpose of improving the functionality of various materials. In particular, it is suitably used for applications such as adding to a resin to control the hardness, slipperiness, water repellency, etc. of the resin, and imparting a temperature-sensitive function by utilizing the melting behavior due to temperature changes. There is.

For example, Patent Document 1 proposes adding a wax such as pentaerythritol fatty acid ester or dipentaerythritol fatty acid ester to a resin to improve the mold releasability during injection molding. Further, the same document discloses that the resin is imparted with releasability by exuding wax from the inside of the resin due to a change in temperature or a change with time.

Further, in Patent Document 2, by using a hydrocarbon wax and an ester wax such as a dipentaerythritol fatty acid ester in combination with a toner resin, the toner is fixed by a heating roller in a printing process from a low temperature. It has been proposed to exude wax to improve mold releasability. Hereinafter, the ease with which wax exudes from the inside of the resin is also referred to as "exudability".

Further, Patent Document 3 proposes to use paraffin wax as a fluid for the thermovalve. It is disclosed that it functions as a heat-sensitive valve that regulates the flow rate of fluid by combining it with the valve body of the piston rod by utilizing the phase transition from solid to liquid and the volume change accompanying thermal expansion and contraction in each phase. (Paragraph [0027] of the same document).

As described above, the volume change due to the temperature change of the wax is used for various purposes, and the amount of the volume change has been adjusted by using various waxes in combination. However, when various waxes are used in combination, the improvement effect is small with a small amount of compounding, so a compounding of several percent or more is required, which affects other physical properties such as melting point, and it is difficult to obtain optimum wax properties. There was a case.

Therefore, there is a demand for an additive capable of increasing the thermal expansion property by adding a small amount to the wax and controlling the exudability and responsiveness with temperature change. In particular, since volume shrinkage is likely to occur before the wax begins to melt, the wax that can cause volume expansion even before the wax begins to melt improves the exudability from the resin by heating for a short time more efficiently. It is strongly requested because it can be expected to be made.

Japanese Unexamined Patent Publication No. 2006-233101 Japanese Unexamined Patent Publication No. 2018-17886 Japanese Unexamined Patent Publication No. 2018-25269

An object of the present invention is to include a wax swelling agent capable of improving the coefficient of thermal expansion of the wax before the wax begins to melt without impairing the basic physical properties of the wax itself by adding a small amount to the wax. Is to provide a wax composition.

As a result of diligent studies in view of the above problems, the present inventors have found that the above problems can be solved by combining a specific fatty acid salt and a specific fatty acid in a specific ratio, and have completed the present invention.

That is, the present invention comprises the following fatty acid magnesium salt (A) and fatty acid (B), and the mass ratio of the fatty acid magnesium salt (A) to the fatty acid (B) [(A) :( B)] is 10 :. It is a wax swelling agent characterized by being 90 to 60:40.
(A) Magnesium salt of monovalent linear saturated fatty acid having 16 to 22 carbon atoms (B) Monovalent linear saturated fatty acid having 16 to 22 carbon atoms

The present invention also contains the wax swelling agent and wax of the present invention, and the content of the wax swelling agent is 0.005 to 1 part by mass with respect to 100 parts by mass of the wax. It is a thing.

According to the wax swelling agent of the present invention, the thermal expansion property of the wax can be enhanced by adding a small amount, so that the influence on the original melting point of the wax is suppressed and the thermal expansion of the wax is performed before the wax begins to melt. The rate can be improved. This makes it possible to control the exudability and responsiveness associated with temperature changes.

Hereinafter, embodiments of the present invention will be described.

<Wax expansion agent>
The wax swelling agent of the present invention comprises the fatty acid magnesium salt (A) and the fatty acid (B) shown below.
(A) Magnesium salt of monovalent linear saturated fatty acid having 16 to 22 carbon atoms (B) Monovalent linear saturated fatty acid having 16 to 22 carbon atoms In addition, it is defined by using the symbol "-" in this specification. The numerical range shall include the numerical values at both ends (upper limit and lower limit) of "~". For example, "2-5" represents 2 or more and 5 or less.

[Fatty acid magnesium salt (A)]
The fatty acid magnesium salt used in the present invention is a magnesium salt of a monovalent linear saturated fatty acid having 16 to 22 carbon atoms.
Specific examples of the fatty acid magnesium salt (A) include magnesium palmitate, magnesium stearate, magnesium arachidic acid, magnesium behenate and the like. Magnesium stearate, magnesium arachidic acid, and magnesium behenate are preferable from the viewpoint of ease of mixing with wax.
One of these fatty acid magnesium salts may be used alone, or a plurality of types may be used in combination. For example, a magnesium salt of a mixed fatty acid may be used.

Examples of the method for producing the fatty acid magnesium salt (A) in the present invention include a direct method and a metathesis method. The direct method is a method in which an oxide or hydroxide of magnesium is reacted with a fatty acid having 16 to 22 carbon atoms. The metathesis method is a method in which a fatty acid having 16 to 22 carbon atoms is reacted with a monovalent alkaline compound to prepare a fatty acid alkaline compound salt once, and then reacted with a divalent magnesium salt in an aqueous solution.

[Fatty acid (B)]
The fatty acid used in the present invention is a monovalent linear saturated fatty acid having 16 to 22 carbon atoms.
Specific examples of the fatty acid (B) include palmitic acid, stearic acid, arachidic acid, behenic acid and the like. Stearic acid, arachidic acid, and behenic acid are preferable because they have a small effect on the melting point of the wax.
One of these fatty acids may be used alone, or a plurality of types may be used in combination. For example, mixed fatty acids may be used.

The wax swelling agent of the present invention has a mass ratio of fatty acid magnesium salt (A) to fatty acid (B) [(A): (B)] of 10:90 to 60:40 and 20:80 to 50:50. Is preferable. When the blending amount of the fatty acid magnesium salt (A) is too small with respect to the fatty acid (B), the change in the melting point of the wax may be large. On the contrary, when the blending amount of the fatty acid magnesium salt (A) is excessive with respect to the fatty acid (B), the compatibility with the wax is lowered and the mixture may not be uniformly mixed.

〔wax〕
The wax used in the present invention is preferably a wax-like compound that melts at a transparent melting point of 50 to 100 ° C., and examples thereof include waxes such as paraffin, fatty acid ester, and amide ester. More preferably, a fatty acid ester obtained by esterifying a monovalent saturated alcohol and a monovalent saturated fatty acid is used. The transparent melting point is more preferably 70 to 90 ° C, still more preferably 60 to 80 ° C.
The transparent melting point can be measured in accordance with JIS K-0064 (Japanese Industrial Standards).

In the fatty acid ester obtained by esterifying a monohydric saturated alcohol and a monovalent saturated fatty acid, the monohydric saturated alcohol to be used is preferably a monovalent linear saturated aliphatic alcohol, and one having 16 to 22 carbon atoms is preferable. More preferred. Among them, stearyl alcohol, arachidyl alcohol, and behenyl alcohol are preferable, and behenyl alcohol is particularly preferable.

Further, as the monovalent saturated fatty acid, a monovalent linear saturated fatty acid is preferable. The number of carbon atoms of the fatty acid is preferably 16 to 22, more preferably 18 to 22. Among these, stearic acid (18 carbon atoms) and behenic acid (22 carbon atoms) are particularly preferable, and stearic acid is even more preferable.
Examples of the method for producing a fatty acid ester include a method using a dehydration condensation reaction between the monovalent saturated alcohol and the monovalent saturated fatty acid. A catalyst may be used to allow the reaction to proceed efficiently. The reaction temperature is preferably 180 to 280 ° C., and the reaction may be carried out under reduced pressure. After the reaction, it may be purified by deoxidation or washing with water.
One type of wax may be used alone, or two or more types may be used in combination. Further, as the monovalent linear saturated fatty acid, a mixture of fatty acid esters obtained by using a mixed fatty acid such as palm oil can also be used.

<Wax composition>
The wax composition of the present invention contains the wax swelling agent and the wax. The content of the wax swelling agent is 0.005 to 1 part by mass, preferably 0.01 to 0.7 parts by mass, and more preferably 0.05 to 0.5 parts by mass with respect to 100 parts by mass of the wax. is there. If the content of the wax swelling agent is too large, the viscosity increases, which may affect physical properties such as the fluidity of the wax.

The wax composition of the present invention can be produced by a known method. For example, it can be produced by heating and melting a wax leavening agent and wax and uniformly mixing them.

The wax composition of the present invention can be blended in, for example, toner. The toner is generally blended with a binder resin, a colorant, an external additive, a charge control agent, and the like, and is produced by a usual manufacturing method. The blending amount of the wax composition of the present invention in the toner is usually 0.1 to 40 parts by mass with respect to 100 parts by mass of the binder resin.

Examples of the wax swelling agent of the present invention and a wax composition containing the same (hereinafter, also referred to as “swelling agent-containing wax”) will be shown below, and the present invention will be described in more detail. It is not limited to the scope of the example.
In the following Examples and Comparative Examples, "%" means a mass reference.

The evaluation methods performed in this example and the comparative example are as follows.
[Evaluation of wax containing leavening agent]
(1) The sample (expansion agent-containing wax) used for the evaluation of the coefficient of linear expansion was prepared by the synthesis method described later. 10 g of the sample is placed in an aluminum cup (diameter 60 mm, height 15 mm) with a smooth bottom and completely melted at 140 ° C., and then a PFA (copolymer of ethylene tetrafluoroethylene and perfluoroalkoxy ethylene) tube ( An inner diameter of 5 mm and a length of 20 mm) was allowed to stand upright in an aluminum cup and cooled and solidified at room temperature. The PFA tube was pulled out from the aluminum cup, and after taking out the cylindrical sample in the PFA tube, the surface of the sample was prepared with a metal file to obtain a wax molded product having a diameter of about 5 mm and a height of about 3 mm.
For the wax molded product, a thermomechanical analyzer (TMA / SS6100, manufactured by Seiko Instruments Inc.) was used to apply a load of 50 mN using a needle-inserted probe with a tip diameter of 1 mm in a nitrogen gas atmosphere at 5 ° C./min. The coefficient of linear expansion from 40 ° C. to 45 ° C. was measured under the heating conditions.
[Evaluation criteria]
◯: The numerical value is positive (indicating volume expansion)
X: Numerical value (indicating volume shrinkage or softening)

(2) Melting point The melting point of the sample (swelling agent-containing wax) was measured by JIS K 0064 using an automatic melting point measuring device (FP62, manufactured by METTLER TOLEDO Co., Ltd.) using a light transmission method.
[Evaluation criteria]
Evaluation was performed using the melting point change rate (%) shown in the following formula.
Melting point change rate (%) = | (melting point of sample) / (melting point of blank) x 100-100 |
◯: (melting point change rate) <0.5
Δ: 0.5 ≦ (melting point change rate) ≦ 0.1
X: (melting point change rate)> 0.1

[Preparation of magnesium stearate (A1)]
Add 3000 g (0.9 mol) of water and 255 g (0.9 mol) of stearic acid to a 5 L glass flask, raise the temperature to 85 ° C. with stirring, add 71 g (0.85 mol) of a 48% aqueous sodium hydroxide solution, and add the same temperature. Stirring was continued for 30 minutes to obtain an aqueous sodium stearate solution. At the same temperature, 165 g (0.48 mol) of a 35% magnesium sulfate aqueous solution was added dropwise over 1 hour, and after completion, the temperature was raised to 90 ° C. and stirring was continued for 1 hour to obtain a magnesium stearate slurry. The obtained slurry was cooled to 60 ° C. or lower, charged in a centrifugal dehydrator having a diameter of 30 cm, dehydrated, and 5000 g of tap water was added into the dehydrator to wash the cake. The obtained dehydrated cake was dried at 60 ° C. for 60 hours to obtain magnesium stearate.

[Preparation of magnesium behenic acid salt (A2)]
Magnesium behenate was obtained by the same method as in the preparation of magnesium stearate (A1) except that stearic acid was replaced with behenic acid.

[Preparation of ester wax]
800 g (2.4 mol) of behenyl alcohol and 720 g (2.5 mol) of stearic acid were added to a 2 L glass flask equipped with a thermometer, a nitrogen introduction tube, a stirrer, a Dean-Stark trap and a Dimroth condenser, and 250 under a nitrogen stream. The reaction was carried out at atmospheric pressure for 12 hours while distilling off the water generated by the reaction at ° C. to obtain a crude esterified product.
To this crude esterified product, 152 g of toluene and 89 g of isopropanol were added, 111 g of a 10% potassium hydroxide aqueous solution equivalent to 1.5 times the acid value of the crude esterified product was added, and the temperature was 70 ° C. for 30 minutes. Stirred. After allowing to stand for 30 minutes, the aqueous layer was removed to complete the deoxidation step. Next, 55 g of ion-exchanged water was added, and the mixture was stirred at 70 ° C. for 30 minutes and then allowed to stand for 30 minutes to remove the aqueous layer portion. Washing with water was repeated 3 times until the pH of the removed aqueous layer became neutral. The ester layer was reduced under reduced pressure at 180 ° C. and 1 kPa to distill off the solvent, and filtration was performed to obtain behenyl stearate.

[Preparation of leavening agent-containing wax]
(Example 1)
20 g of magnesium stearate (A1) and 80 g of stearic acid (B1) were added to a 0.3 L glass flask equipped with a stirring blade and a nitrogen introduction tube, and the mixture was stirred at 140 ° C. for 10 minutes under a nitrogen stream. Then, it was cooled, solidified, and pulverized to obtain a wax swelling agent.
Subsequently, 300 g of the ester wax and 0.75 g of the wax expansion agent were added to a 0.5 L glass flask equipped with a stirring blade and a nitrogen introduction tube, and the mixture was stirred at 140 ° C. for 10 minutes under a nitrogen stream. Then, through cooling, solidification, and pulverization, a leavening agent-containing wax (wax composition) was obtained.

(Examples 2 to 4, Comparative Examples 1 and 2)
The leavening agent-containing wax (wax composition) shown in Table 1 was prepared by the same operation as in Example 1. The content of the wax swelling agent is a mass part with respect to 100 parts by mass of the wax.

As shown in Table 1, the blank wax containing no wax swelling agent has a negative linear expansion coefficient (α) due to volume shrinkage or softening, but the swelling agent-containing wax of Examples 1 to 4 It was shown that the coefficient of linear expansion (α) became a positive value and the volume expanded. Moreover, in all the examples, the rate of change of the melting point was small and the evaluation was “◯”. Therefore, it was shown that the leavening agent-containing waxes of Examples 1 to 4 improve the thermal expansion property with almost no change in the melting point of the wax.

On the other hand, in Comparative Example 1 and Comparative Example 2, the effect of improving the coefficient of linear expansion (α) was not obtained. Further, in the system in which the fatty acid (B) alone was added in Comparative Example 2, the rate of change in the melting point was slightly high, and the evaluation was “Δ”.

Claims (2)

It is composed of the fatty acid magnesium salt (A) and the fatty acid (B) shown below, and the mass ratio of the fatty acid magnesium salt (A) to the fatty acid (B) [(A): (B)] is 10:90 to 60:40. A wax swelling agent characterized by being.
(A) Magnesium salt of monovalent linear saturated fatty acid having 16 to 22 carbon atoms (B) Monovalent linear saturated fatty acid having 16 to 22 carbon atoms A wax composition containing the wax swelling agent and wax according to claim 1, wherein the content of the wax swelling agent is 0.005 to 1 part by mass with respect to 100 parts by mass of the wax.