JP3425768B2 - Granulated antistatic agent and method of using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a kneading type antistatic agent for synthetic resins and a method of using the same, more specifically, a master for mixing and adding resin pellets and antistatic agent, mainly in a molding maker. The same handling as master pellets is possible without using pellets,
And an antistatic agent granulated product that is excellent in antistatic effect after addition,
And how to use it.

[0002]

2. Description of the Related Art Although synthetic resin products are excellent in electrical insulation, they are easily charged with static electricity and have problems such as dirt and dust adhesion due to static electricity. It is known to add various antistatic agents to synthetic resin products for use in order to prevent such adverse effects during use. The antistatic agent used at this time includes a coating type in which a resin is applied to a molded product after molding, and a kneading type in which the resin is kneaded in advance and molded, but in order to maintain the antistatic effect, the kneading is performed. The crowded type is superior, and the latter is more frequently used.

In the case of the kneading type, as a method of kneading the antistatic agent into the resin, a method of adding a raw material of the antistatic agent to a synthetic resin powder in a liquid form by a resin maker, or a powder of the antistatic agent is used. A general method is to mix and knead the mixture with other resin additives.

On the other hand, apart from such a kneading method, a molding maker generally adds an antistatic agent in the form of a master pellet to a general-grade resin pellet containing no antistatic agent, if necessary. Is. A master pellet is a specific resin containing an antistatic agent in an amount of 5 to 1
Kneaded in advance to a concentration of 0% by weight, easy to mix with general grade resin, no powdering, etc.
It has the advantage of being easy to handle. On the other hand, a kneading operation is required in advance to manufacture the master pellet, which leads to a cost increase. Further, when the conventional master pellets are used, there is a drawback that it takes some time to develop the antistatic effect.

[0005]

Under these circumstances, an antistatic agent which has the same handling property as the master pellets in the molding maker without using the master pellets and leads to the cost reduction of the adding operation step. It is desired to improve the shape and develop a method of adding it to the resin.

It is generally known that when various additives are mixed and added to a synthetic resin, these additives are granulated and used. However, these are mainly for the purpose of facilitating handling at the time of adding the additive to the melting tank or the hopper, and in reality, the additive is in a molten state, and the melt addition is performed. Should be considered On the other hand, it is necessary to mix and add the antistatic agent to the resin so that the antistatic agent is uniformly dispersed in the resin, but since kneading with a molding machine is not sufficient, the antistatic agent is granulated. It can be said that mixing and adding to the resin by the same use method as that of the master pellet has hardly been performed. Japanese Unexamined Patent Publication (Kokai) No. 60-84339 proposes only a pellet-shaped antistatic composition for polyolefin resin, which comprises an antiblocking agent, a higher fatty acid metal salt and an antistatic agent. However, this has a drawback that the content of the antistatic agent is 65% by weight or less, and an unnecessarily large amount of an inorganic substance or a metal salt of a higher fatty acid must be blended in order to maintain the granularity.

As described above, the reason why it was not so general to directly mix the resin pellets and the antistatic agent granules for molding was that the plasticizing step of the molding machine alone was sufficient. This is because it has been considered that kneading and dispersion are not performed.

The object of the present invention is to have the same handling property as the master pellets in order to solve such problems.
It is an object of the present invention to provide an antistatic agent granule and a method of using the same, which can reduce the cost of the adding operation step, exhibit an antistatic effect quickly, and do not have the drawbacks described in the above publications.

[0009]

[Means for Solving the Problems] To achieve the above object,
As a result of intensive investigations by the present inventors, the same handling as that of a master pellet is possible when granulated to have an average particle size of 2 to 7 mm using a specific antistatic agent,
The present invention has been completed by finding that the cost can be reduced during the operation of adding an antistatic agent to a resin, and that a better antistatic effect can be obtained than when using a master pellet.

That is, the gist of the present invention is (1) N, N-bis (2-hydroxyethyl) steari
50% by weight or more of ruamine, and α-glycero
Antistatic, free of lumonostearate and synthetic resin
The inhibitor composition was granulated to have an average particle size of 2 to 7 mm.
Granules characterized by antistatic agent, (2) Average grain composed of stearic acid monoglyceride
An antistatic agent granule having a diameter of 2 to 7 mm, and (3) promoting the development of the antistatic effect of the antistatic agent
A method of using the obi according to (1) or (2) above
The antistatic agent granules are mixed with resin pellets, which
Judgment based on the surface resistivity value of adding an antistatic agent to oil
The use of antistatic agents that promote the development of antistatic effects
About the use method.

The antistatic agent granulated product of the present invention comprises N, N-bis (2-hydroxyethyl) stearylamine and / or
Or stearic acid monoglyceride, and optionally other known antistatic agents for synthetic resins,
It is characterized in that it is composed mainly of an antistatic agent without containing a synthetic resin. N, used in the present invention,
The total content of N-bis (2-hydroxyethyl) stearylamine and / or stearic acid monoglyceride is usually 25% by weight or more, preferably 40% by weight.
It is above 80% by weight. If it is less than 25% by weight, a sufficient antistatic effect cannot be obtained, which is not preferable. Further, N, N-bis (2-hydroxyethyl) stearylamine or stearic acid monoglyceride may be used alone or in combination.

As other known antistatic agents for synthetic resins which can be further used as necessary, various kinds of antistatic agents can be used, but they are solid at room temperature and exhibit excellent effects. , Stearic acid diethanolamide,
Representative examples include sodium alkane sulfonate, stearyl alcohol, lauric acid diethanolamide, and lauric acid monoglyceride.

The N, N-bis (2-hydroxyethyl) stearylamine in the present invention can be easily obtained by the reaction of adding 2 moles of ethylene oxide to stearylamine, and a commercially available product can also be used. The stearic acid monoglyceride of the present invention is obtained by the esterification reaction of stearic acid and glycerin, but it is generally obtained as a mixture of monoester, diester and triester. In the present invention, so-called high-purity stearic acid monoglyceride having a high monoester content is preferable.

The present invention is characterized in that the antistatic agent composition does not contain a binder component such as a synthetic resin when the granulated product is obtained. As the property of the granulated product, it may be preferable to contain a synthetic resin as in the case where blocking is a problem when placed at a high temperature. However, containing a synthetic resin means that an antistatic agent is added to the resin. It becomes a temperature higher than the melting point of, causing decomposition and volatilization, which is rather undesirable. The antistatic agent granules of the present invention have almost the same particle size as the resin pellets, and since the granule surface can be coated with an antiblocking agent such as silica, it is excellent without containing a synthetic resin. Product properties can be maintained.

On the other hand, when the antistatic agent granules are prepared using only stearic acid diethanolamide or sodium alkanesulfonate, which is added as necessary as described above, and added to the resin, However, it is possible to obtain only the same effect as that of the addition in the master pellet, or an effect less than that. That is, it is possible to granulate stearic acid diethanolamide or sodium alkanesulfonate by a known method, but when this granulation product is mixed with resin pellets and molded, the lubricity is too strong, Kneading is not performed, and as a result, the physical properties of the resin are adversely affected, and the antistatic effect is insufficient, so that it cannot be used.

As a granulation method for obtaining the antistatic agent granulated product of the present invention, known techniques can be used. That is, a method of dropping a molten compound on the cooled belt surface and granulating it into a hemispherical shape, a method of extruding into a noodle shape from a die in a semi-molten state, and granulating into a cylindrical shape can be used. The particle size of the antistatic agent granulated product of the present invention thus obtained is usually 2 to 7 mm, preferably 4 to 5 mm, and it is preferable that the particle size is substantially the same as that of the resin pellet. If the particle size is too small compared to the resin pellets, the particles are classified in the molding machine hopper, and uniform mixing is not performed, which is not preferable. On the other hand, if the particle size exceeds 7 mm and is too large, it may cause a problem in fluidity as well as classification with resin pellets, which may cause a hopper bridge, which is not preferable.

The method of using the antistatic agent granulated product of the present invention is as follows:
The above antistatic agent granules are directly mixed with resin pellets and added to the resin. At this time, the mixing method of the resin pellets and the granulated product of the present invention is not particularly limited and does not require a special device or method and may be the same as the case of using the conventional master pellets. The amount of the antistatic agent granulated product used at that time is 0.1 to 3% by weight based on the resin pellets. When the amount is less than 0.1% by weight, a sufficient antistatic effect cannot be obtained, and when the amount is more than 3% by weight, bleeding becomes excessive and the surface properties of the molded product deteriorate (stickiness), which is not preferable.

When the method of using the antistatic agent granulated product of the present invention is used, the effect is observed earlier than when the same antistatic agent is used in the form of master pellets, and the antistatic performance is improved. Can be realized at the same time. The reason for this is that when master pellets are used, the antistatic agent that is uniformly dispersed in the master pellets is kneaded again, and the dispersion in the resin is too good, which results in bleed-out on the surface of the molded product. While it takes time, it is presumed that when the granulated product of the present invention is used, the kneading is performed once, so that the dispersion in the resin is appropriate and the effects are rapidly exhibited. In the case of producing a master pellet, since the antistatic agent is heated to a temperature higher than the melting temperature of the resin used, it is considered that the antistatic agent may be volatilized or decomposed, and it is presumed that the effect is reduced. .

In the granulated product of the present invention, the blocking property of the granulated product may become a problem when the operating temperature is too high. In this case, the surface of the granulated product may be uniformly coated with an inorganic powder such as silica. Granules 1
0.05 to 1.0 parts by weight is suitable for 100 parts by weight,
If the amount is larger than this, the inorganic powder is peeled off from the surface of the granulated product, causing a problem such as scattering of the powder. Here, the average particle size of the inorganic material is preferably 1 to 5 μm. The granulated product of the present invention may be added to resin pellets in combination with pigment master pellets and the like.

[0020]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Examples 1 to 5 The compositions shown in Table 1 were granulated to an average particle size of 4 to 5 mm using a Sandvik funnel former granulator.
For Examples 1 to 4, 0.5 parts by weight of silica (Mizukasil P-526) manufactured by Mizusawa Chemical Co., Ltd. was used with respect to 100 parts by weight of the granulated product.
Part by weight was added and mixed for 30 seconds with a Henschel mixer to adhere to the surface of the granulated product. This antistatic agent granule is made of polypropylene resin (PP-JHHG manufactured by Mitsui Toatsu Chemicals, Inc.)
0.5 part by weight was added to 100 parts by weight of the pellet.
The mixing of the pellets was done manually using a polyethylene bag. The pellet mixture thus obtained was put into an injection molding machine hopper, and a test piece was molded at a cylinder temperature of 240 ° C. In addition, in Example 5, a test piece was molded using an antistatic agent granulated product not surface-coated with silica manufactured by Mizusawa Chemical. These test pieces were left in a constant-humidity room at a constant temperature of 23 ° C. and a humidity of 50%, and a high resistance meter (Yokogawa / Hewlett-Packard Co.,
(4329A type) was used to measure the surface resistivity over time to measure the antistatic effect. The results are shown in Table 1.

[0022]

[Table 1]

Comparative Examples 1-7 The same antistatic agent as in Examples 1-5 was used, or Table 2
Using the respective antistatic agents shown in Comparative Examples 6 to 7 above, master pellets were produced by the following method. First, the powdered antistatic agent and polypropylene resin powder product were mixed in a Henschel mixer, extruded into a strand using a 40 mm extruder, further cooled with water, cut and dried to obtain an antistatic agent master pellet. This was mixed with polypropylene resin pellets in the same manner as in the example and injection molded. Further, the antistatic effect was measured over time by the same method as in the examples. The results are shown in Table 2.

Comparative Example 8 A granulated product was prepared in the same manner as in Examples 1 to 4 using sodium alkane sulfonate as an antistatic agent, mixed and added to polypropylene resin pellets, and similarly molded and evaluated. The results are shown in Table 2.

Comparative Example 9 Molding was carried out in the same manner as in Examples 1 to 4 using only polypropylene resin pellets without adding an antistatic agent, and evaluated. The results are shown in Table 2.

[0026]

[Table 2]

From the above results, the antistatic agent granules of Examples 1 to 5 of the present invention all have a small surface specific resistance,
In particular, when the surface resistivity was observed with time, it was found that the surface resistivity was reduced after one day, and the antistatic effect was rapidly developed. On the other hand, in Comparative Examples 1 to 5 in which the same antistatic agent as in Example was used as the master pellets, the antistatic effect was slow to develop, and in Comparative Examples 6 to 8 in which the antistatic agent of the present invention was not used. However, the antistatic effect itself was insufficient even when the granulated product was used as in Comparative Example 8.

[0028]

The antistatic agent granules of the present invention are used to
When mixed with resin pellets and molded, compared to the case of using master pellets, handling properties are equivalent, and there is no need to knead into the resin in advance and the addition amount is small, so low cost Can be kneaded into the resin, and has an advantage that the antistatic effect is rapidly exhibited.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C09K 3/16 102 C09K 3/16 102 103 103 (56) References JP-A-52-90543 (JP, A) JP-B-47 -11652 (JP, B1) JP-B 47-40313 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09K 3/16 C08K 3/00 C08K 5/10 C08K 5/17 C08K 7/00

Claims (3)

(57) [Claims] 1. N, N-bis (2-hydroxyethyl)
The Suteariruami emissions contain more than 50 wt%, and α- grayed
An antistatic agent granulated product, characterized in that an antistatic agent composition containing neither lyserolol monostearate nor a synthetic resin is granulated to an average particle size of 2 to 7 mm. 2. A monoglyceride stearate.
An antistatic agent granulated product having an average particle size of 2 to 7 mm. 3. The development of the antistatic effect of the antistatic agent is promoted.
A method of using the method according to claim 1 or 2,
Mix the antistatic agent granulate with the resin pellets,
Judgment based on the surface resistivity value of adding an antistatic agent to the resin
Of antistatic agents that promote the development of antistatic effect
how to use.