JP2874249B2 - Colorant composition and blow-molded article colored with the composition - Google Patents

Description

The present invention relates to a colorant composition for imparting a pearl appearance to a blow molded article of a polypropylene resin, and a blow molded article made of polypropylene which is pearl colored with the composition. About.

[Conventional technology]

Conventionally, blow-molded colored bottles made of polypropylene are often used for containers for detergents and cosmetics. In this case, as a bottle molding method, a coloring agent is put into a hopper of an extruder type blow molding machine together with a polypropylene resin, heated, melted, kneaded to extrude a colored parison, and then the colored parison is sandwiched by a mold, By blowing air, a method of forming a colored bottle is adopted, and as a coloring agent used in the production of such a colored bottle, rutile-type titanium, iron oxide, inorganic pigments such as ultramarine blue and azo-based pigments, There are organic pigments such as cyanine, and these colorants are sufficiently kneaded with the polypropylene resin, uniformly dispersed, and extruded into a parison having a smooth surface (skin). A bottle with an external appearance is obtained and has excellent commercial value.

[Problems to be solved by the invention]

However, recently, in order to give a pearly feeling to the container from the aspect of design, pearl coloring using mica (mica) pearl pigment has been frequently used, but polypropylene resin is blown by the same blow molding method as before. When a bottle is formed by mixing mica pearl pigments into the bottle, several or many streaks are generated in the longitudinal direction (extrusion direction) of the bottle around the welded portion, or irregularly in color unevenness, Further, there is a problem that only the pearl pigment is partially aggregated to cause poor appearance.

That is, a polypropylene resin and mica pearl pigment are charged from a hopper 2 of a blow molding extruder 1 as shown in FIG. 1, and these molding materials are heated, melted and kneaded with the rotation of a screw 3, and from the hopper 2 side. When the parison (pipe extrudate) 6 is extruded toward the die 4 and extruded from the die nozzle 5, the parison 6 is extruded as shown in FIG. The mica pearl pigment 10 separates from the kneaded material and adheres to the surface wall 7 and the outer surface wall 9 of the core 8, respectively. Further, the pearl pigment agglomerates and accumulates over time, so that a smooth die and core The surface does not lose its smoothness and scratches the parison 6 extruded therefrom, resulting in numerous streaks and impairing the appearance of the blow molded bottle.

The kneaded material extruded from the hopper 2 toward the die 4 is passed through a breaker plate 11 to remove dirt and the like. At this time, the mica of the pearl pigment is scale-like or laminated quadrilateral. Therefore, the pearl pigment may be caught on the surface of the screen mesh attached to the breaker plate 11, the separated pearl pigment may accumulate on the outermost part of the screen mesh due to the difference in flow characteristics with the resin, In some cases, the aggregates are randomly discharged, and the aggregates are discharged at random, resulting in partial aggregation of the pearl pigment, which causes poor appearance of the bottle.

In addition, the appearance defect as described above may be caused by using a molding material color-compounded with a coloring agent such as a dry color or a master batch before putting into a blow molding machine, or using a coloring agent such as a master batch at the time of blow molding. Also, even in a method of mixing with a diluting resin and introducing the mixture into a molding machine, the problem occurs as long as a pearl pigment manufactured by My Car is used.

As a method of solving such a problem, there is a method of periodically removing the pearl pigment stuck to the die and the core and replacing the screen mesh in the breaker plate, but this method stops the operation of the molding machine. To do
The operating rate is reduced, and cleaning and replacement work is troublesome. In addition, the heating, melting, and kneading in the blow molding extruder, screw shape is changed to strengthen the kneading, the structure is changed so that the extrusion pressure is not excessively applied to the die, and the mica pearl pigment is removed from the kneaded material. Dies and cores may be manufactured using a metal that does not adhere even when separated, or methods such as finishing the wall of the dies and core may be considered. However, these methods have economical problems, and may be made by mica. Since there is no problem in forming a bottle without using a pearl pigment, it is not advisable to improve the molding machine.

The present invention has been made in view of the above circumstances, and can solve the above-described problem of poor appearance that occurs when a mica pearl pigment is used, and provides a good pearl appearance using a normal blow molding machine as it is. It is an object of the present invention to provide a mica pearl pigment-containing colorant composition capable of providing a polypropylene blow molded article having the same, and a polypropylene blow molded article pearl-colored with the composition.

[Means and Actions for Solving the Problems]

The present inventors have solved the problem that the mica pearl pigment agglomerates and adheres to the breaker plate, die, core wall and the like of the blow molding machine with the elapse of operation time, and this causes the appearance defect of the polypropylene blow molded product. As a result of intensive studies, it has been found that it is effective to mix an acid-modified polypropylene with a mica pearl pigment as a colorant composition.

That is, when a colorant composition containing a mica pearl pigment blended with an acid-modified polypropylene is mixed with a polypropylene resin, and a molded article having a pearl appearance such as a bottle is molded using a usual blow molding machine, the mica pearl is used. The pigment does not aggregate or adhere to the breaker plate, die, core wall, etc. of the blow molding machine even after the operation time has elapsed, and therefore, appearance defects such as streaks, uneven color, and partial aggregation occur in the appearance. Blow-molded products with excellent pearl appearance are molded stably, so there is almost no occurrence of molding defects due to appearance defects, and the operation of the blow molding machine is stopped to remove mica pearl pigments and replace parts It has been found that the economical effect is extremely large, for example, such that it is not necessary to carry out the present invention, and the present invention has been accomplished.

Accordingly, the present invention provides a colorant composition for coloring a polypropylene blow molded article with a mica pearl pigment, wherein the mica pearl pigment is mixed with an acid-modified polypropylene, and The present invention provides a pearl-colored polypropylene blow molded article with an agent composition.

 Hereinafter, the present invention will be described in more detail.

The colorant composition of the present invention comprises a mica pearl pigment and an acid-modified polypropylene.

Here, the acid-modified polypropylene is obtained by graft-polymerizing a functional group such as a carboxyl group to a polypropylene resin, and the functional groups include the following,
A copolymer of two or more of these functional groups may be used.

(R represents a lower alkyl group such as a methyl group and an ethyl group.) The density of acid-modified polypropylene is 0.89 ~ 0.91g / c
c, Mass flow rate (MFR) is 0.1-10g / 10min, especially 1
~ 5g / 10min is preferred.

The mica pearl pigment is a fine mica having a laminated structure, and any pigment generally used as a pigment can be used, and can be selected in consideration of a desired appearance. Those having a diameter of about 5 to 200 μm are preferable, and pearl pigments obtained by treating mica with titanium are preferably used in order to further develop a pearly feeling, and a titanium coupling agent, a silane coupling agent, or the like is further used as a treatment agent. May be.

The colorant composition of the present invention may contain ordinary polypropylene in addition to the acid-modified polypropylene and mica pearl pigment.

As this polypropylene, those used for blow molding are preferable, and for example, the density is 0.89 to 0.91 g /
Those having cc and MFR of 0.15 to 2.5 g / 10 min can be suitably used.

The colorant composition of the present invention contains these acid-modified polypropylene, mica pearl pigment and, if necessary, polypropylene. The content of these acid-modified polypropylene is 1 to 99.7% (% by weight, Same), preferably 10-40%, mica pearl pigment 0.3-50%,
Preferably 0.3 to 10%, 0 to 98.7% polypropylene,
Preferably, it is 50 to 90%. If the content of the mica pearl pigment is less than 0.3%, a molded article having a pearl appearance intended for the present invention cannot be obtained, while if it contains more than 50%, the dispersibility of the mica pearl pigment becomes poor, In some cases, poor appearance of the molded article may occur. On the other hand, if the content of the acid-modified polypropylene is less than 1%, the dispersibility of the mica pearl pigment becomes poor, and the above-mentioned poor appearance of the molded product may also occur.

In the colorant composition of the present invention, other pigments, antioxidants, antistatic agents and the like may be appropriately blended depending on the taste of the molded article to be obtained in addition to the above components. .

The colorant composition of the present invention can be obtained by mixing, heating, melting and kneading the above-mentioned components according to a conventional method, and can be usually used in the form of pellets.

In addition, a method for producing a polypropylene blow molded product having a pearl appearance using this colorant composition can be performed in the same manner as in the case of using a normal colorant using a normal blow molding machine. .

The polypropylene blow-molded article thus obtained has a smooth and excellent pearl appearance without vertical streaks, color unevenness and pearl pigment aggregation, and is of high commercial value.

〔The invention's effect〕

As described above, according to the colorant composition of the present invention, a blow-molded product made of polypropylene having a pearl-like appearance of excellent quality without poor appearance can be stably used without any improvement in a blow-molding machine. It can be molded and
The molding efficiency is also remarkably improved, and the economic effect is extremely large.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Examples, Comparative Examples)

Maleic anhydride-based acid-modified polypropylene A (MFR2.0
g / 10min, density 0.89g / cc) and acrylic acid-based acid-modified polypropylene B (MFR3.0g / 10min, density 0.91g / cc), according to the following method, the mica pearl having the composition shown in Table 1. Seven kinds of coloring master batches containing a pigment were prepared, and using these master batches, a polypropylene bottle was extruded and blow-molded by the following method.

Next, the appearance of the obtained bottle was observed, and the presence or absence of streaks and color unevenness was examined. The results are shown in Table 1.

Preparation Method of Colored Masterbatch A composition having the composition shown in Table 1 was put into a Banbury mixer, heated, melted and kneaded at about 180 to 200 ° C., and mica pearl pigment was dispersed in polypropylene and acid-modified polypropylene. Thereafter, the mixture was pulled out into a belt shape by a mixing roll and formed into a square pellet by a square pelletizer. Furthermore, in order to adjust the shape of the coloring master batch,
The mixture was melt-extruded at 180 to 200 ° C. and granulated into round pellets.

Extrusion blow molding method 10 parts by weight of the colored master batch prepared above was mixed with 200 parts by weight of polypropylene (Mitsui Petrochemical, B-278),
L / D: 20, die / core: 9.3 × 9.7 / 4φ Put into the hopper of the molding machine, set the temperature of the cylinder and die to 180-200 ° C, heat, melt, knead and extrude blow molding did.

From the results in Table 1, it can be seen that the molded product using the colored masterbatch of Comparative Example in which the mica pearl pigment was simply dispersed in polypropylene without blending the acid-modified polypropylene had streaks, uneven color, and no commercial value. Things. On the other hand, the molded article using the master batch of the product of the present invention containing the acid-modified polypropylene had no streaks and uneven color and had an excellent appearance.

In addition, the reference photographs 1 to 3 show sectional micrographs of the molded product. Here, Reference Photos 1 and 2 show the state of the streak portion formed in the molded article according to the comparative example not containing the acid-modified polypropylene. Reference Photo 1 is a magnification of 40 times, and Reference Photo 2 is a magnification of a reference.
400 times. Further, Reference Photo 3 is a cross-sectional micrograph of a molded article according to an example in which the acid-modified polypropylene was blended at a magnification of 400 times, which shows that the use of the acid-modified polypropylene can prevent the formation of streaks.

Also, before the blow molding, the colored master batch and polypropylene are mixed, kneaded, and extruded in advance to produce colored pellets, and even if blow molded, products having a composition that does not contain acid-modified polypropylene will have streaks and uneven color. The product having a composition containing the acid-modified polypropylene had no streaks or color unevenness.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an extruder of a blow molding machine, and FIG. 2 is a schematic diagram showing a state of a parison extruded from a die nozzle. DESCRIPTION OF SYMBOLS 1 ... Blow molding extruder, 2 ... Hopper, 3 ... Screw, 4 ... Die, 5 ... Die nozzle, 6 ... Parison, 7 ... Die inner surface wall, 8 ... Core, 9 ... Core outer surface wall, 10: Mica pearl pigment, 11: Breaker plate

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Shozo Fukuchi 655 Namiki-cho, Narita City, Chiba Prefecture (56) References JP-A-63-179972 (JP, A) JP-A-49-21445 (JP, A) ( 58) Field surveyed (Int.Cl. ⁶ , DB name) C09C 1/00 3/12 C08L 23/00-23/36 C08L 51/06

Claims (2)

(57) [Claims] 1. A colorant composition for coloring a blow molded article made of polypropylene with a mica pearl pigment, wherein the mica pearl pigment is mixed with an acid-modified polypropylene. 2. A blow molded article made of polypropylene, which is pearl-colored with the colorant composition according to claim 1.