JPH0598096A - Antistatic granular masterbatch composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. excellent in blocking resistance, good in processability and capable of imparting good antistatic properties and pigment dispersion properties esp. to a polyolefin resin. CONSTITUTION:The title compsn. comprises 80-95wt.% non-crystalline polypropylene formed as a by-product in preparation of a polypropylene random copolymer and having a melt viscosity of 500 to 3,500cP, and 20-5wt.% antistatic agent.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel antistatic masterbatch granular composition, and more particularly, to a good processability without blocking itself.
In particular, the present invention relates to an antistatic masterbatch granular composition mainly composed of amorphous polypropylene, which gives good antistatic properties and high pigment dispersibility when blended with a synthetic resin such as a polyolefin resin.

[0002]

2. Description of the Related Art Generally, a synthetic resin, for example, an olefin polymer such as polyethylene or polypropylene has a large electric insulating property and easily accumulates static electricity. Sleeping,
In general, antistatic treatment is performed because it may cause problems in secondary processing such as printing and painting.

This antistatic treatment is carried out by a method of applying an antistatic surfactant, that is, an antistatic agent on the surface,
The antistatic agent can be roughly classified into two methods of kneading the antistatic agent into the inside. In the latter method of adding the internal kneading type antistatic agent, the raw material resin and the antistatic agent are dried at the time of molding. There is a method of blending and a method of using a masterbatch in which an antistatic agent is kneaded in a resin in a high concentration in advance at the time of molding, and in particular, a method of using a masterbatch, because the antistatic agent can be easily mixed, Widely used for practical use.

As such a masterbatch, a masterbatch for polypropylene resin in which an antistatic agent is kneaded into amorphous polypropylene is used (Japanese Patent Publication No. 47-48889), which is amorphous. Although it is economically advantageous in using a water-resistant polypropylene, the antistatic effect varies depending on the resin grade and molding conditions, so it is necessary to increase the addition amount of the antistatic agent to obtain a stable antistatic effect. However, as a result, there are drawbacks such as stickiness of the molded product and powder blowing phenomenon. Further, since the masterbatch itself has high tackiness, the granulated product tends to cause blocking, resulting in poor workability.

In order to improve the drawbacks caused by such tackiness, a resin mainly composed of amorphous polypropylene is added.
It has been proposed that 5 to 25% by weight of a surfactant be added and mixed by mixing (Japanese Patent Publication No. 50-33513), but the composition thus obtained has sufficient performance as an antistatic agent masterbatch. It does not satisfy.

Further, as a composition which does not change the antistatic effect of the masterbatch granules depending on the resin grade, molding conditions, etc., a composition in which a specific antistatic agent component is combined has been proposed (JP-A-63-113051). Bulletin,
JP-A-63-113052). However, this composition is limited in the antistatic agent component that can be used, and in addition, it is recommended to use a small amount of silicon dioxide together for the purpose of improving the blocking property of the masterbatch granules. However, the blocking property cannot be sufficiently prevented, and there is a difficulty in handling the masterbatch itself.

Further, even if the conventional antistatic agent master batch has good dispersibility in polypropylene resin, for example, a pigment is added at the same time as the antistatic agent master batch in order to obtain a colored resin composition. if you did this,
There is a problem in that good dispersibility of the pigment cannot always be obtained, and it is difficult to uniformly color the pigment, especially for a color tone having high brightness.

[0008]

Under the circumstances described above, the present invention does not cause blocking itself, gives good antistatic properties when blended with a resin, and disperses pigments. The purpose of the present invention is to provide an antistatic agent masterbatch granular composition mainly composed of amorphous polypropylene which is not damaged.

[0009]

The present inventors themselves have
As a result of earnest research to develop a masterbatch granular composition that is easy to handle and can impart good antistatic properties without any obstacles when compounded with a synthetic resin, polypropylene random copolymer production It was found that the object can be achieved by a granular composition containing an amorphous polypropylene having a specific melt viscosity and an antistatic agent, which are sometimes by-produced, in a predetermined ratio, and the present invention was completed based on this finding. Came to do.

That is, according to the present invention, 80 to 95% by weight of (A) an amorphous polypropylene having a melt viscosity of 500 to 3500 cps at a temperature of 180 ° C., which is a by-product during the production of a polypropylene random copolymer, and (B) an antistatic agent 20. ~ 5
And an antistatic agent masterbatch particulate composition comprising 100% by weight.

In the composition of the present invention, amorphous polypropylene is used as the component (A). Amorphous polypropylene is generally obtained as a by-product during the production of crystalline polypropylene, and block copolymers, random copolymers, and homopolymers are known, but in the present invention, random copolymers are used. It is necessary to use polymeric by-products.

When a by-product of a block copolymer or a homopolymer is used, it is necessary to use crystalline polypropylene in combination because amorphous polypropylene itself has a strong adhesive property and tends to cause blocking ( JP 63-
No. 30546).

In the present invention, the amorphous polypropylene is a by-product in the production of a polypropylene random copolymer, and has a melt viscosity at a temperature of 180 ° C. in the range of 500 to 3500 cps. When such an amorphous polypropylene is used, an antistatic agent composed of a nonionic surfactant is added in a proportion of 5 to 20% by weight based on the total weight of the amorphous polypropylene, It is possible to obtain a granular composition having no blocking property and excellent in blocking resistance.

The melt viscosity of the amorphous polypropylene is 50.
If it is less than 0 cps, the obtained antistatic agent masterbatch granular composition cannot avoid solidification due to blocking at any antistatic agent concentration, and is 3500.
When it exceeds cps, the pigment dispersibility is deteriorated like other amorphous polypropylene, so that a bright and uniform color tone having high brightness cannot be obtained.

The antistatic agent used as the component (B) in the composition of the present invention may be a nonionic surfactant, which is generally known as a kneading type antistatic agent, There is no particular limitation. Examples of such an antistatic agent include polyoxyethylene alkylamine, N, N-bis (2-hydroxyethyl) alkylamine, fatty acid ester of N, N-bis (2-hydroxyethyl) alkylamine, higher alcohol, Examples thereof include fatty acid esters of polyhydric alcohols, polyoxyethylene, fatty acid esters, polyoxyethylene fatty alcohols, polyoxyethylene alkyl phenyl ethers, and the like. These antistatic agents may be used alone or in combination of 2
You may use it in combination of 2 or more types.

In the composition of the present invention, the antistatic agent as the component (B) must be used in a proportion of 5 to 20% by weight based on the total amount of the amorphous polypropylene as the component (A). Is. If this amount is less than 5% by weight, the proportion of the amorphous polypropylene in the molded product will be large, and the physical properties of the molded product will be impaired, and the dispersibility of the pigment will tend to worsen. If it exceeds%, the dilution ratio of the masterbatch becomes large, resulting in an unfavorable situation such as non-uniform antistatic effect in the molded product and uneven color.

The method for producing the granular composition of the present invention is not particularly limited, and a conventionally known method for granulating amorphous polypropylene can be used. For example, a predetermined proportion of amorphous polypropylene and an antistatic agent are mixed and melted, and after continuously adhering to a rotary cooling drum, the end is stripped off to form a continuous sheet having a thickness of 2-3 mm, The sheet is cut into square pellets by a square pellet machine to prepare a granular composition.

The granular composition of the present invention may contain, if desired, stabilizers such as antioxidants and ultraviolet absorbers, lubricants, nucleating agents, pigments, and inorganic fillers as long as the object of the present invention is not impaired. Additives that are commonly used such as can be mixed. The amount used is appropriately selected according to the purpose of the additive.

Examples of the antioxidant include butylated hydroxytoluene, n-octadecyl-β- (hydroxy-3 ', 5'-di-tert-butylphenyl) propionate, 4,4'-butylidenebis (3-tertiary). Butyl-m-
Cresol), 1,1,3-tris (2-methyl-4-)
Hydroxy-5-tert-butylphenyl) butane and the like can be mentioned.

Examples of UV absorbers are p-tert-butylphenyl salicylate, 2-hydroxy-4-n-octoxybenzophenone, 2,2'-dihydroxy-4.
-Methoxybenzophenone, 2- (2'-hydroxy-
5'-methylphenyl) benzotriazole and the like.

Examples of the lubricant include synthetic paraffin, polyethylene wax, higher fatty acid amide and ethylenebis fatty acid amide, and examples of the nucleating agent include silica, aluminum hydroxide, talc, metal fatty acid salt,
Examples include calcium carbonate.

As the pigment, both organic pigments and inorganic pigments can be used, but preferred are monoazo red, quinacridone red, polyazo red, cyanine blue,
Examples include polyazo yellow, cyanine green, quinacridone violet, cadmium red, cadmium yellow, titanium white, and red iron oxide.

The resin to which the antistatic agent masterbatch granular composition of the present invention is applied is, for example, low density polyethylene (LDPE), high density polyethylene (HDPE),
Examples thereof include polyolefin resins such as linear low-density polyethylene (LLDPE), polypropylene (PP) or copolymers thereof.

The polyolefin resin containing the masterbatch granular composition of the present invention can be molded by any processing method such as injection molding, blow molding, extrusion molding and the like.

[0026]

The antistatic agent masterbatch granular composition of the present invention is mainly composed of amorphous polypropylene, which is a by-product during the production of a polypropylene random copolymer, and is itself resistant to blocking. A molded product that is excellent in processability, has excellent antistatic properties when compounded with a synthetic resin, has good pigment dispersibility, and can produce a particularly bright and bright color tone evenly. Can be provided.

[0027]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto. The evaluation was performed as follows.

(1) Blocking property 1 kg of the masterbatch composition was packed in a plastic bag, and 1
A load of 0 kg was applied, the sample was left in a constant temperature chamber at 40 ° C. for 1 month, and after 1 month, the presence or absence of blocking was visually determined according to the following criteria.

◯: No blocking is observed, and it easily collapses. Δ: There is some blocking, and a strong force is required for loosening. X: Blocking is remarkable, and pellet lumps do not collapse.

(2) Antistatic property The surface resistivity 30 minutes after molding and 1 month after molding was measured with a Hiresta surface resistivity meter manufactured by Mitsubishi Petrochemical at a temperature of 20 ° C.
The measurement was performed in a constant temperature and constant humidity state with a relative temperature of 65%.

(3) Lightness The lightness (L value) of the surface of the molded product on the first day after molding was measured by an SM color computer spectrocolorimeter made by Suga Test Instruments Co., Ltd. The better the pigment dispersibility, the higher the brightness.

(4) Color unevenness The occurrence of color unevenness of the molded product was visually evaluated according to the following criteria. ◯: No uneven color is observed. Δ: Some color unevenness is observed. X: Significant color unevenness is observed.

Examples 1 to 6, Comparative Examples 1 to 6 Granular compositions were prepared by using the amorphous polypropylene polymer shown in Table 1 and the antistatic agent B-1 or B-2 in the proportion shown in Table 2. ..

First, the amorphous polypropylene polymer was charged into a compounding tank equipped with a paddle type stirrer and melted, and then the antistatic agent was melted and mixed under a nitrogen stream, and then this mixture was continuously transferred to a rotary cooling drum. The particles were adhered and stripped from one end to form a continuous sheet having a thickness of 2 to 3 mm, and the sheet was shredded into square pellets by a square pellet machine to prepare a granular composition.

Next, the composition was treated with a commercially available polypropylene (Idemitsu Polypro J-700G) containing an antistatic agent of 0.1.
After blending so as to be 4% by weight, 1.0% by weight of TAIPAKE CR-60 (titanium white: manufactured by Ishihara Sangyo) and Paliogen Red 3911HD (B
ASF) 0.02% by weight and zinc stearate 0.1
A pigment composition was blended in a weight percentage, and a molded product was prepared by an injection molding machine of Nissei Resin TS-150.

The performance of these molded products was evaluated.
The results are shown in Table 2. The antistatic agent B-1 was a glycerin monostearate / stearyl alcohol mixture (weight ratio 50/50), and B-2 was a glycerin monostearate / N, N-bis (2-hydroxyethyl) hardened tallow amine mixture ( The weight ratio is 50/50).

[Table 1]

[Table 2] (Note) In the molded product of Comparative Example 3, the rigidity was remarkably reduced, and the characteristics of the polypropylene molded product were lost.

Claims (1)

[Claims] 1. A melt viscosity at a temperature of 180 ° C., which is a by-product during the production of the polypropylene random copolymer (A), is 50.
0-3500 cps amorphous polypropylene 80-95
An antistatic agent masterbatch particulate composition comprising 20% to 5% by weight of (B) an antistatic agent.