JP3390828B2 - Anhydrous azodicarbonamide crystal and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an anhydrous azodicarbonamide crystal product and a method for producing the same.

[0002]

2. Description of the Related Art Azodicarbonamide (hereinafter referred to as "ADC
A) is conventionally widely used as a foaming agent for thermoplastic resins such as vinyl chloride resin, polyolefin resin (polyethylene resin, polypropylene resin, etc.), ethylene vinyl alcohol resin, etc. This is usually a fine powdery crystalline substance, which is agglomerated and solidified with the passage of time or a load, which deteriorates the fluidity in the addition step to the resin and clogs the hopper, or deteriorates the dispersibility in the resin. I have a problem. In recent years, as the quality of foamed resins has been improved and labor for manufacturing has been reduced, further improvement in solidification has been desired.

[0003]

At present, in order to solve such problems, (1) a method of adding inorganic powder particles such as silica and metal silicate as a solidification inhibitor to a foaming agent, (2) ) A method is adopted in which the drying method is a batch method, a sufficient drying time is taken, and a small amount of water contained in the foaming agent is reduced.

However, when these methods are adopted, various drawbacks occur. That is, in the method (1),
Although some solidification-preventing effect is observed, the effect is maintained for only a few months. In addition, since the effect becomes less when the foaming agent becomes fine particles, it is necessary to add more inorganic powder particles, but addition of a large amount of inorganic powder particles causes coarsening of the bubbles at the time of foaming, so It is not preferable in applications requiring a large cell. On the other hand, in the method (2),
It takes a long time to dry, and it is difficult to sufficiently dry and remove the water inside the crystals to obtain a substantially anhydrous ADCA crystal product, and the solidification preventing effect is also limited.

Japanese Patent Laid-Open No. 4-320432 discloses an AD
A method has been proposed in which a silane coupling agent dissolved in a solvent is added to CA to improve fluidity and dispersibility in a resin. However, the method could not sufficiently prevent solidification.

Further, Japanese Unexamined Patent Publication (Kokai) No. 8-295872 proposes a method of improving fluidity and dispersibility in a resin by adding an aluminum-based coupling agent dissolved in a solvent to ADCA. . However, even this method could not sufficiently prevent solidification.

[0007]

Means for Solving the Problems As a result of earnest research to solve the above problems, the present inventors
By treating with a surface treatment agent having a property of removing water from the ADCA crystal product, a substantially anhydrous ADCA crystal product is obtained, and the solidification property of the ADCA product is remarkably suppressed, and the ADCA crystal product exhibits fluidity and resin even after a long period of time. It has been found that it is extremely useful as a foaming agent having good dispersibility and the like.
The present invention has been completed based on such knowledge.

That is, the present invention provides a substantially anhydrous ADCA.
Relates to crystalline material.

Further, the present invention uses ADCA crystals as ADCs.
The present invention relates to a substantially anhydrous ADCA crystal obtained by treating with a surface treating agent having a property of removing water from a crystalline substance A and then heating.

In addition, the present invention provides an ADCA crystal product as AD
A method for producing an ADCA crystal, which comprises treating with a surface treating agent having a property of removing water from a CA crystal in the absence of a solvent and then heating to obtain a substantially anhydrous ADCA crystal. Pertain.

The substantially anhydrous ADCA crystal product of the present invention has remarkably improved solidification property under load and solidification property over time, hardly solidifies even after long-term loading and storage, and has good fluidity immediately after production. And the dispersibility in the resin is maintained for a long time.

The foaming performance of the ADCA crystal of the present invention is equivalent to that of conventional ADCA.

Accordingly, the substantially anhydrous ADCA of the present invention.
The provision of the crystalline material eliminates the fear of solidification under load and solidification with time from the production of ADCA to the use by the user.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, "substantially anhydrous"
Means that the water content is less than 0.03% by weight, preferably 0.0
It means less than 15% by weight. Here, the water content (wt%) is measured by heating the ADCA crystal to be measured at 110 ° C. for 2 hours while passing a nitrogen gas containing no water, so that the outflowing nitrogen gas does not enter the water from the outside air. Karl Fischer moisture meter (trade name: MKS-1,
(Made by Kyoto Electronics Co., Ltd.) to measure the water content in the nitrogen gas,
This water content was obtained as a percentage with respect to the weight of the ADCA crystal.

Particularly, the substantially anhydrous ADCA crystal of the present invention has substantially no surface-adhered water or surface-pore water.

The particle size of the ADCA crystal of the present invention is not particularly limited, but it is usually 1 to 50 μm, preferably about 3 to 30 μm. In the present specification, A
The particle size of the DCA crystal is a median size measured by using a laser diffraction type particle size distribution meter.

The surface treating agent which can be used in the present invention is a surface treating agent having a property of removing water from the ADCA crystalline substance, and such a surface treating agent is a compound having a property of chemically bonding with water. Alternatively, a compound having a property of adsorbing or retaining water is used. Examples of such a surface treatment agent include a coupling agent, an organic acid anhydride, an inorganic compound anhydride, and a desiccant.

Examples of the coupling agent include silane coupling agents, aluminum coupling agents, titanate coupling agents and the like.

As the silane coupling agent, conventionally known ones can be widely used, and methyltrimethoxysilane,
Examples thereof include γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N-phenylaminomethyltrimethoxysilane and vinylmethyldiethoxysilane.

As the aluminum-based coupling agent,
A wide variety of conventionally known compounds can be used, and examples thereof include aluminum isopropylate, aluminum ethylate, aluminum tris (ethylacetoacetate), and ethylacetoacetate aluminum diisopropylate.

As the titanate coupling agent, conventionally known ones can be widely used. Isopropyltriisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, bis (dioctyl pyrophosphate). Examples thereof include phosphate) oxyacetate titanate.

These coupling agents may be used alone or in combination of two or more. These coupling agents have the property of chemically binding to water to adsorb and remove the water in the ADCA crystal product, and also to form a film on the surface of the ADCA crystal to prevent water absorption from the outside. Therefore, it can be used particularly preferably.

As the organic acid anhydride, conventionally known ones can be widely used, and examples thereof include phthalic anhydride, succinic anhydride, glutaric anhydride, benzoic anhydride and trimetic anhydride. These compounds combine with water in the ADCA crystal product to remove it by the following mechanism, for example.

(RCO) ₂ O + H ₂ O → 2RCOOH [In the formula, R represents an organic acid residue. As the anhydride of the inorganic compound, conventionally known ones can be widely used as long as they can bind to water to have water of crystallization, and examples thereof include anhydrous magnesium sulfate, anhydrous potassium carbonate, anhydrous sodium carbonate and sodium sulfate. Anhydrous, anhydrous sodium sulfite,
An anhydrous magnesium carbonate etc. can be mentioned. These compounds are used, for example, in the ADCA mechanism represented by the following.
Water in the crystal substance is adsorbed and fixed as crystal water.

Na ₂ SO ₄ + nH ₂ O → Na ₂ SO ₄ .nH ₂ O [In the formula, n represents an integer of 1 or more. As the desiccant, any conventionally known one can be widely used as long as it has a property of removing water, and examples thereof include acid clay, silica gel, magnesium oxide, calcium oxide and the like.

In the present invention, as the surface treatment agent, the above-mentioned coupling agent, organic acid anhydride, anhydride of inorganic compound and desiccant may be used alone or in combination of two or more. May be.

These surface-treating agents are used to treat the surface of the ADCA crystal product, preferably by heating the ADCA crystal product to obtain ADCA.
The water content in the ADCA crystal can be reduced by efficiently reacting with or adsorbing the water contained in the crystal.

These surface treatment agents are preferably used as they are without being dissolved in a solvent so as not to adversely affect the reaction with water and the adsorption of water. At that time, when a solid surface treatment agent is used, it is preferably used in the form of fine powder or in the form of a melt.

The amount of the surface-treating agent used with respect to the ADCA crystals is usually about 0.01 to 10 parts by weight, preferably 0.05 to 0.
It may be used at a ratio of 5 parts by weight.

In the present invention, it is preferable that the surface treatment agent is added to the ADCA crystal product or after the surface treatment agent is heated to accelerate the reaction between the water in the ADCA crystal product and the surface treatment agent.

The heating temperature is usually 40 to 180 ° C.,
Although preferably up to 55 to 180 ° C., ADC
In order to prevent the decomposition and deterioration of A, it is usually preferable to perform the heating up to 100 ° C. Further, the heating temperature is preferably about 70 to 90 ° C. from the viewpoint of shortening the heating time to perform the mixing more efficiently and minimizing the energy cost.

It is effective to perform heating simultaneously with adding and mixing the surface treatment agent to the ADCA crystal. The addition of the surface treatment agent is preferably performed while mixing the ADCA crystal product.

The mixing device that can be used for the above mixing is not particularly limited, but examples thereof include screw mixers such as super mixers, Hensiel mixers and Nauta mixers, proshear mixers, ribbon type blenders and the like. it can. However, A which became substantially anhydrous
Since the hygroscopicity also increases when the DCA crystal substance is also crushed to increase the specific surface area, the Nauta mixer, the proshear mixer (using the shear blades removed), the ribbon type blender, etc. are less likely to be sheared and the crushing of the particles is suppressed. It is desirable to use a mixer such that the increase in the specific surface area after the treatment is within 20%, more preferably within 10% as compared with that before the treatment.

When a liquid surface treatment agent is used, it is preferable to spray the surface treatment agent in the form of fine droplets onto the ADCA crystal using a pressure nozzle or a two-fluid nozzle when adding the surface treatment agent. By spraying the surface treatment agent in the form of fine droplets on the ADCA crystal product, the anhydrous ADCA crystal product of the present invention can be obtained by using a small amount of the surface treatment agent.

The anhydrous ADCA crystal product of the present invention is the same as the conventional A
Like the DCA crystal, it can be preferably used as a foaming agent for various synthetic resins.

In using the anhydrous ADCA crystal product of the present invention, stabilizers, pigments and fillers known in the art,
It can also be used as a foaming agent composition containing a foaming inhibitor or the like. Examples of such stabilizers include tribasic lead sulfate, dibasic phosphite, lead stearate, zinc stearate, zinc carbonate, zinc oxide, barium stearate, and the like.
Aluminum stearate, calcium stearate,
Examples thereof include dibutyl tin malate and urea. Examples of the pigment / filler include chrome yellow, carbon black, titanium dioxide, calcium carbonate and the like.
Further, examples of the foaming inhibitor include maleic acid and the like.

[0037]

EXAMPLES The present invention will be further clarified with reference to Examples and Comparative Examples below. Hereinafter, simply "%" means "% by weight".

The ADCA used in this example is Otsuka Chemical Co., Ltd. and has an average particle diameter of 20 μm.

Example 1 To 25 kg of ADCA, 50 g of aluminum tris (ethylacetoacetate) (trade name: ALCH-TR, manufactured by Kawaken Fine Chemical Co., Ltd.) was melted by heating at 90 ° C. and was added by spray spraying to form a conical ribbon type blender. (Product name: Ribocorn ERME-50, manufactured by Okawara Seisakusho Co., Ltd.) was mixed at 70 rpm and 90 ° C. for 10 minutes, and then the mixture was further mixed for 7.5 minutes under the same conditions.
A CA crystal product was obtained.

Example 2 N- (β-aminoethyl) -γ-in 25 kg of ADCA
Aminopropyltrimethoxysilane (trade name: TSL8
340, manufactured by Toshiba Silicone Co., Ltd.) at 90 ° C., while adding 50 g by spray spraying, using a conical ribbon type blender (product name: Ribocon ERME-50, manufactured by Okawara Seisakusho) at 70 rpm, 90 ° C. After mixing for 1 minute, the mixing was continued for another 7.5 minutes under the same conditions, and
A DCA crystal was obtained.

Example 3 To 25 kg of ADCA, 50 g of glutaric anhydride was added by spraying at 80 ° C., while using a conical ribbon blender (product name: Ribocon ERME-50, manufactured by Okawara Seisakusho) at 70 rpm and 90 ° C. At that time, after mixing for 10 minutes, the mixing was continued for another 7.5 minutes under the same conditions, and
A DCA crystal was obtained.

Comparative Example 1 N- (β-aminomethyl) -γ-into 25 kg of ADCA
Aminopropyltrimethoxysilane (trade name: TSL8
340, manufactured by Toshiba Silicone Co., Ltd.) 50 g of water 1 kg
Prepare an aqueous solution diluted to a super mixer (product name,
(Kawata Manufacturing Co., Ltd.) at 600 rpm at room temperature for 10 minutes, followed by 7.5 minutes of mixing under the same conditions, and after drying, an ADCA crystal product of Comparative Example 1 was obtained.

Comparative Example 2 The untreated ADCA was used as the ADCA crystal of Comparative Example 2.

Test Example 1 With respect to each of the foaming agent powders obtained in the above Examples and Comparative Examples, the water content (residual water content) was measured, the sedimentation solidification test, and the actual packaging solidification test were conducted by the following methods. The results are shown in Table 1.
Shown in.

(1) Measurement of water content: 10 g of a sample was precisely weighed in a flask and heated at 110 ° C. for 2 hours while passing nitrogen gas containing no water. At this time, the Karl Fischer moisture meter (trade name: MKS-, which prevents the moisture from the outside air from entering the nitrogen gas flowing out from the flask)
1. The amount of water (g) in nitrogen gas was measured by passing through Kyoto Electronics Co., Ltd.).

The water content is defined by the following formula: water content (%) = (water content / precisely weighed sample quantity) × 10
It was calculated by 0.

(2) Deposition solidification test: 400 g of sample
Was packed in a 23 × 13 cm plastic bag and thoroughly degassed,
The openings were heat-sealed and stacked, and a load of 0.08 kg / cm ^{2 was} further applied from above. After 10 days, the sample was taken out, sieved with a 14-mesh sieve, the amount of the non-passage was measured, and the value obtained by converting into% was taken as the deposition solidification value.

(3) Real package solidification test: sample 25k
g in a cardboard case, which is a product distribution package,
The sample was allowed to stand for 1 month under the conditions of a temperature of 40 ° C. and a humidity of 80%, then sieved with a 14-mesh sieve to measure the amount of non-passages, and the value obtained by converting into% was taken as the solidified solidification value. .

[0049]

[Table 1]

ADCs of Examples 1, 2 and Comparative Example 2
Comparing the test results for the A crystal substance, it can be seen that the anhydrous ADCA crystal substance of the present invention is significantly suppressed in solidification as compared with the untreated blowing agent powder.

Further, from the comparison of the test results of the foaming agent powders of Example 2 and Comparative Example 1, even in the surface treatment with the silane coupling agent, the heat treatment is performed without using a solvent, so that the desired anhydrous form of the present invention can be obtained. It can be seen that an ADCA crystal product is obtained and the solidification prevention property is greatly improved.

Test Example 2 15 parts by weight of each ADCA crystal obtained in Example 1, Example 2, Example 3 and Comparative Example 2 (provided that ADCA crystal of Example 1, Example 2 and Example 3 was used). For Test Example 1
The composition obtained by blending 100 parts by weight of low-density polyethylene (melt index 2.0) and 0.8 part by weight of dicumyl peroxide was used for the roll temperature of 110 to 115 ° C. After kneading while heating in a sheet with a thickness of 5 mm and taking it out, 12
A pressure of 120 kg / cm ² was applied for 5 minutes at 5 ° C. and heated to obtain a pressed sheet. Then, the obtained sheet is 2
Foaming was performed using a hot air oven set at 20 ° C.

The foams obtained were obtained from Example 1, Example 2 and
The cells using the ADCA crystallized products of both Example 3 and Comparative Example 2 were fine and uniform cells, and were good foams having substantially the same surface smoothness and decomposition rate.

From these results, the anhydrous ADCA crystalline material of the present invention was tested for A after being manufactured even after a long time under load.
It can be seen that it has a foaming performance equivalent to that of the DCA crystal product.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshifumi Tate, 615, Hanafuri, Satoura-cho, Satoura-cho, Naruto City, Tokushima Prefecture Inside the Naruto Plant, Otsuka Chemical Co., Ltd. (72) Shigeru Sumitomo 463 Kagasuno, Kawauchi-cho, Tokushima City, Tokushima Prefecture Otsuka Chemical Co., Ltd. Company Tokushima Factory (56) Reference JP 4-320432 (JP, A) JP 8-295872 (JP, A) JP 6-179862 (JP, A) JP 50-87455 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C07C 281/00 C08J 9/00

Claims (5)

(57) [Claims] 1. An azodicarbonamide crystalline product having a water content of less than 0.015% by weight . 2. The method according to claim 1, which is obtained by treating the azodicarbonamide crystal product with a surface treating agent having a property of removing water from the azodicarbonamide crystal product, and then heating it to 55 to 180 ° C. azodicarbonamide crystals of. 3. The azodicarbonamide crystal product according to claim 2, wherein at least one selected from a coupling agent, an organic acid anhydride, an anhydride of an inorganic compound and a desiccant is used as a surface treatment agent. 4. The azodicarbonamide crystal product is treated in the absence of solvent with a surface treating agent having a property of removing water from the azodicarbonamide crystal product, and then treated with 55 to 18
A method for producing an anhydrous azodicarbonamide crystal, which comprises heating to 0 ° C. to obtain an azodicarbonamide crystal having a water content of less than 0.015% by weight . 5. When treating an azodicarbonamide crystal product with a surface treating agent having a property of removing water from the azodicarbonamide crystal product in the absence of a solvent, 55 to 1
A method for producing an anhydrous azodicarbonamide crystal, which comprises heating to 80 ° C. to obtain an azodicarbonamide crystal having a water content of less than 0.015% by weight .