JPS6313420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing zinc salt of acrylic acid,
More specifically, when producing zinc acrylate by reacting acrylic acid and a zinc compound, the reaction is carried out in a solvent in the absence of water, and then stearic acid is added to the reaction solution and stirred, This invention relates to a method for producing zinc acrylate, which is characterized by drying.

Conventionally, it is well known to obtain zinc acrylate by reacting acrylic acid and a zinc compound in a solvent, and then removing the solvent under reduced pressure after the reaction is completed, or drying under reduced pressure after filtration. According to this method, the reaction product sticks to the inner wall of the reactor or the stirring blade, or forms large lumps, which causes problems in the process, resulting in a significantly low yield.

Furthermore, when the solvent is removed under reduced pressure, the solvent contained in the produced zinc acrylate is scattered, but at the same time, the zinc acrylate is also violently scattered, resulting in poor yield and difficulty in recovering the solvent. Becomes,
The disadvantage was that there was also a large economic loss.

As a method for overcoming the above drawbacks, the present inventors have
After various studies, it was found that after the reaction between acrylic acid and zinc compound in a solvent is completed, 5 to 20 parts by weight of acrylic acid added to the reaction solution in the solvent.
By adding and stirring a solution in which part by weight of stearic acid is dissolved by heating, or adding and stirring stearic acid to a reaction solution heated to 40°C to 90°C and then drying, the above drawbacks can be overcome and the desired powder can be obtained. It was found that a solid in the form of a solid can be obtained, and the present invention was completed.

Thus, the present invention provides an industrially extremely advantageous method for producing zinc acrylate powder that overcomes the drawbacks of conventional production methods, and produces zinc acrylate powder with high yield and which is extremely easy to operate and control. The present invention provides a method.

Furthermore, when zinc acrylate is blended into rubber with a radical polymerization initiator such as peroxide, it reacts with heat and acts as a co-crosslinking agent, but the above peroxide does not cause ionic decomposition in an acidic region. Easy to wake up,
In addition, stearic acid is known to act as an organic acid when blended with rubber or other polymers, and therefore, blending stearic acid into peroxide vulcanizate systems has a negative impact on the physical properties of the vulcanizate. This is an undesirable thing and has not been done in the past.

In this way, the applicant has now discovered that by adding stearic acid, which has been considered unsuitable for peroxide vulcanization systems, during the production of zinc acrylate, the production yield can be significantly increased. For example, the zinc acrylate of the present invention is incorporated into the inner core of a golf ball, particularly a solid ball or a two-piece ball (usually composed of zinc white and peroxide as a specific gravity adjusting agent, as well as a co-crosslinking agent and polybutadiene).
When used as a co-crosslinking agent, the physical properties of the resulting vulcanized balls were extremely good, contrary to expectations that the physical properties would be markedly degraded due to ion decomposition of the peroxide.

Furthermore, the physical properties of the vulcanized product (e.g.,
It was also observed that the inner core hardness and durability were further improved. Furthermore, the feel and sound of the two-piece golf ball produced using this golf ball when hit were sufficiently satisfactory as a golf ball.

Hydrocarbon compounds are suitable as the solvent used in the present invention, and specific examples include methanol, benzene, toluene, xylene, n-heptane, and n-heptane.
-Hexane, etc.

The acrylic acid used in the present invention is ordinary acrylic acid that is not diluted with water, but it may contain some amount of water. Furthermore, the mixture of polymerization inhibitors such as hydroquinone and hydroquinone monomethyl ether contained in acrylic acid does not cause any problem.

The zinc compound used in the present invention is an ordinary powdery solid. Specific examples of zinc compounds include zinc oxide, zinc hydroxide, zinc carbonate, and zinc bicarbonate.

The reaction temperature between acrylic acid and the zinc compound is not particularly limited, but is preferably 90°C or lower. If the reaction temperature is too high, a partial polymerization reaction will occur, resulting in poor product purity.

Stearic acid may be added to a solution heated and dissolved in a solvent, or stearic acid may be added to a reaction-completed solution.

The present invention will be explained below with reference to Examples.

Example 1 600 g of zinc oxide and 2000 ml of toluene were placed in a jacket-type vertical mixer (No. 5) and suspended while stirring. Next, 1060 g of acrylic acid was added dropwise over 30 minutes and mixed, followed by a reaction at room temperature for 60 minutes. Ta.
After the reaction is complete, add 130g of stearic acid to 100ml of toluene.
In addition to this, add a solution heated and dissolved at 45-50℃,
Stir for 30 minutes to form a slurry and coat the product with stearic acid. Then 50℃, 120
The mixture was heated under reduced pressure of ~60 mmHg for 3 hours to distill out produced water and toluene and dry. 1620 g of stearic acid coated zinc acrylate was obtained. The loss on heating was 0.3%. When drying under reduced pressure,
Almost no scattering of the produced zinc acrylate was observed, and no adhesion to the inner wall of the reactor was observed. Further, even after drying, the particles remained fine and no lumps were observed.

The same can be said for all Examples 2 to 4 below.

Example 2 1400 g of zinc oxide and 1960 ml of toluene were placed in a 10 jacket kneader and kneaded to homogenize. Next, while continuing the kneading operation, acrylic acid 2477
g was added dropwise over 60 minutes, and the reaction was carried out at 40 to 50°C for 1 hour. After the reaction was completed, 376 g of stearic acid was added, the temperature was raised to 75° C. while kneading, and the mixture was stirred for 30 minutes to coat the product with stearic acid.
Next, heat for 2 hours under reduced pressure of 300 to 200 mmHg,
The produced water and toluene were distilled off, and drying was continued to obtain 3720 g of zinc acrylate. The heating loss of this product was 0.25%.

Example 3 2,260 g of zinc oxide and 2,000 ml of methanol were placed in a 10-capacity jacket-type kneader and kneaded to form a slurry, and then 4,000 g of acrylic acid was added to 30
Dropped in minutes. After reacting for 1 hour after dropping, 820 g of stearic acid was added and kneaded at a temperature of 40 to 50°C to perform coating. Next, steam was passed through the jacket to distill methanol out at a temperature of 70°C, and then the jacket was taken out from the kneader and dried in a low-temperature dryer at 40°C. 6290 g of zinc acrylate was obtained. The loss on heating was 0.25%.

Example 4 900 g of zinc oxide and 3000 ml of benzene were placed in a jacket-type vertical mixer (No. 5), stirred and mixed to make a suspension. Next, 1590 g of acrylic acid was added dropwise over 30 minutes while stirring and mixed, and the mixture was heated to 60 ml at room temperature. A minute reaction was carried out. After the reaction is complete, add 80g of stearic acid to benzene.
In addition to 500 ml, add the solution heated and dissolved at 45-50℃, stir and mix for 30 minutes, and mix the resulting slurry.
Hot water at 50° C. was passed through the jacket under a reduced pressure of 275 to 100 mmHg and heated for 2 hours to distill out produced water and benzene. Drying was continued to obtain 492 g of zinc acrylate coated with stearic acid.
The volatile matter content of the obtained product was 0.25%.

Comparative Example 1 The same procedure as in Example 1 was carried out, except that after the reaction was complete, stearic acid was added to toluene and a heated solution was added to coat the product.

When drying under reduced pressure was carried out after completion of the reaction, zinc acrylate was significantly scattered and entered the distilled solvent, making its recovery difficult. In addition, the recovery of zinc acrylate scattered in the reactor, the cleaning of the reactor, and the removal of reactants stuck to the inner wall of the reactor are quite complicated, and the resulting zinc acrylate is also lost due to sticking and scattering. Most were 1120gr. It was observed that some of the particles formed into large lumps as they dried, and it was quite difficult to crush them.

Comparative Example 2 Zinc acrylate obtained in Comparative Example 1 was crushed in a pulverizer to
When 30 parts by weight of the powder crushed to a size of 17μ was kneaded with 100 parts by weight of polybutadiene rubber using a 6-inch roll, significant aggregates of 0.5 mmφ were formed in the rubber, and there was also significant adhesion to the roll surface. I did it.

Claims (1)

[Claims] 1. After reacting acrylic acid and a zinc compound, stearic acid is added to the reaction solution at a ratio of 5 to 20 parts by weight per 100 parts by weight of the acrylic acid while stirring, followed by drying. A method for producing zinc acrylate coated with stearic acid, characterized by: 2. The method for producing zinc acrylate according to item 1, wherein heating is performed at 40 to 90°C.