JPH08325422A - Colorant composition for polypropylene - Google Patents

Abstract

(57) [Summary] [Object] To provide a high pigment concentration colorant composition having excellent pigment dispersibility when molding polypropylene such as injection, extrusion, and hollow molding. A colorant composition for polypropylene comprising a carrier resin comprising an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer and a low molecular weight olefin resin and a pigment. [Effect] Since the pigment dispersibility is excellent during polypropylene, injection, extrusion, or color molding such as hollow molding, it is possible to prevent color unevenness and color streaks, and improve the product appearance and moldability. As a result, the concentration of the pigment in the colorant can be increased, so that the amount of the colorant used can be reduced, the coloring cost can be reduced, the strength of the molded article can be prevented from lowering, and the molding property can be greatly reduced to reduce the molding cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colorant composition in which a pigment can be easily distributed in a molded article by molding polypropylene.

The colorant composition of the present invention can be used in any molding method such as injection, extrusion and hollow molding.

[0003]

2. Description of the Related Art In recent years, polypropylene has been used for a wide range of applications because it has improved moldability and physical properties due to improvements in catalysts and polymerization methods and is easily recycled.

Particularly, a highly crystalline isotactic polypropylene having an isotactic pentad of more than 98% has been used as a polypropylene having high rigidity and high heat resistance for automobile parts and home electric appliances.

Generally, coloring of plastics is carried out for the purpose of imparting various properties such as decorativeness to a molded product, and a powdery, granular or liquid coloring agent is used at the stage of injection molding or extrusion molding. The colorant is obtained by adding a dispersion aid to a pigment or dye as a coloring component, or by adding a resin to it, and simply mixing or melt-kneading the mixture. The coloring component changes variously.

A pigment is used for coloring polypropylene, but the powder colorant with the dispersion aid added thereto causes environmental pollution due to its handling, and the measuring accuracy in an automatic weighing machine is poor, so that the shape of the colorant is changed. Changes are being called for.

Conventionally, various colorants have been proposed to meet such requirements, but granular colorants, commonly known as masterbatch colors, are often used as one of the most suitable colorants.

The masterbatch color is a product obtained by concentrating the pigment required for coloring a polypropylene molded product to a maximum of about 60% by weight and kneading it in an appropriate carrier resin (vehicle resin) in good dispersion. is there. Therefore, at the stage of injection molding or extrusion molding, it is diluted with the resin used for molding before use.

[0009]

DISCLOSURE OF THE INVENTION Problems to be solved when diluting a masterbatch color into polypropylene are distributability (peptizability) of the masterbatch color to a molded product. However, if the pigment concentration of the masterbatch color is increased in order to increase the dilution ratio (decrease the blending ratio of the masterbatch color to the resin to be colored) in consideration of economic efficiency, the masterbatch color has a high melt viscosity. Therefore, insufficient kneading by the molding machine occurs, and uneven distribution and color streaks, which are poor distribution phenomena, occur.

In such a case, as a measure for eliminating color unevenness and color streaks, conventionally, a material having good fluidity was used as a vehicle resin for masterbatch color, such as polyethylene or polypropylene, in which the dilution ratio was reduced by decreasing the pigment concentration of the masterbatch color. A method of using the same, a method of using another olefin resin, or a method of increasing the kneading conditions of the molding machine have been adopted. However, the method of reducing the dilution ratio and increasing the kneading conditions increase the coloring cost, and it is meaningless to aim at economical efficiency.

On the other hand, attempts have been made to change the masterbatch color vehicle resin, for example, Japanese Patent Laid-Open No. 1-2614.
No. 40 discloses that a masterbatch color made of a pigment and a binary or ternary amorphous polyolefin is an olefin resin such as polyethylene or polypropylene, an acrylonitrile styrene butadiene copolymer, or a resin such as polyvinyl chloride. Is disclosed as a technique for improving color unevenness. Further, JP-A-5-202234 discloses a copolymer of a monomer having an α, β unsaturated double bond and a dibasic acid having an unsaturated double bond or an anhydride thereof as a vehicle for a masterbatch color. It has been shown that what is contained is extremely effective for coloring polyolefins in which physical properties such as mechanical properties and heat resistance are particularly important. Further, in Japanese Patent Publication No. 6-21201, a masterbatch color composed of a pigment, an ethylene-vinyl acetate copolymer, a polyolefin wax and a carboxylic acid-containing polyolefin wax has a high pigment content, but an olefin resin or a styrene resin. It is disclosed as a coloring composition which has good pigment dispersion and can be easily distributed at the time of molding to not only general-purpose resins such as resins but also engineering plastics having high processing temperatures such as polyamide and polyacetal.

However, these disclosed masterbatch colors have a problem that they are ineffective against resins such as polypropylene and highly crystalline polypropylene containing fillers.

An object of the present invention is to provide a granular colorant having good distribution, which does not cause color unevenness or color streaks in the molding process of polypropylene, particularly polypropylene containing a filler or highly crystalline polypropylene.

[0014]

Under the circumstances, the inventors of the present invention have earnestly studied to improve the distribution of the granular colorant, and as a result, a specific ethylene-α olefin copolymer or propylene-α olefin copolymer When used as a vehicle resin for masterbatch color by combining the union and a low molecular weight olefin resin, it has excellent distributability during color molding such as polypropylene injection molding, extrusion molding or hollow molding, so that uneven coloring and color streaks do not occur. Found.

That is, the present invention relates to a colorant composition for polypropylene comprising a carrier resin comprising an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer and a low molecular weight olefin resin and a pigment.

The present invention will be described in detail below. The ethylene-α-olefin copolymer or propylene-α-olefin copolymer used in the present invention is synthesized by solution polymerization or the like using an organometallic compound such as a Ziegler catalyst as a catalyst. In the present invention, any shape such as powder and granules is not required, but in the case of ethylene-α olefin copolymer, ethylene-propylene copolymer or ethylene-butene obtained by binary copolymerizing propylene or butene-1 with ethylene. -1 copolymer and a ternary copolymer obtained by adding any one of non-conjugated dienes such as dicyclopentadiene, methyltetrahydroindene, methylene norbornene, ethylidene norbornene and 1,4 hexadiene as a third component. A polymer is included. Similarly, the propylene-α-olefin copolymer includes a propylene-butene-1 copolymer obtained by copolymerizing propylene with butene-1.

If desired, these two copolymers may be used in combination. Further, even if these copolymers have an acid group such as α, β-unsaturated carboxylic acid or an anhydride thereof in the molecule by post-treatment after the polymerization, there is no problem in the present invention.

In both of these binary or ternary copolymers, the α-olefin component ratio is 3 to 95% by weight, and the softening point and the density change depending on the component ratio, but it is desirable that it softens at 140 ° C. or lower. .

As such a material, Nippon Synthetic Rubber Co., Ltd.
JSR EP (trade name), Mitsui Petrochemical Co., Ltd. Tuffmer (trade name), Exxon Chemical Co., Ltd. Vistalon (trade name), Mitsui EPT (trade name) and Sumitomo Chemical Co., Ltd. Esplen (trade name) ) Can be given.

The low molecular weight olefin-based resin used in the present invention is an ethylene-based resin having a molecular weight of 500 to 6000, and is intended for all resins obtained by polymerization of monomers and all resins obtained by thermal decomposition of polymers. it can. In addition, even if an acid group of an α, β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid or itaconic acid or its anhydride is introduced into the molecule by post-treatment to these resins, There is nothing wrong with the invention.

The pigment used in the present invention is well known in the field of plastics processing, and examples thereof include inorganic pigments such as titanium oxide, zinc oxide, rouge, titanium oxide calcined pigment, ultramarine blue, cobalt aluminate and carbon black. Azo-based, quinacridone-based, anthraquinone-based, perylene-based, isoindolinone-based, phthalocyanine-based, quinophthalone-based, slene-based, organic pigments such as diketopyrrolopyrrole-based, and extender pigments such as barium sulfate, calcium carbonate, and talc is there.

The colorant composition of the present invention contains a pigment, an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer and a low molecular weight olefin resin as essential components, but has a low density as a part of the carrier resin. Add olefinic resins such as polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, etc., or heat stabilizers, light stabilizers, flame retardants, plasticizers, lubricants or fillers to improve the suitability for use. be able to.

The constituent ratio of the essential components of the colorant composition of the present invention is such that the pigment is 1 to 70% by weight, preferably 5 to 60% by weight.
The total amount of the carrier resin excluding the pigment is at least 30% by weight of both the ethylene-α-olefin copolymer or the propylene-α-olefin copolymer and the low molecular weight olefin resin, and both resin components are 1% by weight. : 4 to 4:
It should be within the range of 1.

The granular colorant is obtained by mixing the essential components of the colorant with other components as desired, and thoroughly melt-kneading them. For example, a pigment is previously mixed with a low molecular weight olefin resin by a high speed mixer or the like, and after kneading with a Banbury mixer or a kneader, the pigment is finely ground by a heating two roll or a heating three roll, A product obtained by kneading an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer and other components with a kneading machine such as a twin-screw or twin-screw extruder, or by mixing all these components at once. , Banbury mixer, kneader,
It is a product obtained by melt-kneading with a high-speed rotating intensive mixer, a twin screw extruder or the like. The shape of the kneaded product may be hot cut to give granules or cold cut sheets or strands to give granules depending on how the kneaded product is taken out from the kneader.

The resin to be colored by the colorant of the present invention is isotactic polypropylene, syndiotactic polypropylene, polypropylene modified with a comonomer, polypropylene reinforced with a filler or the like, highly crystalline polypropylene, etc. The coloring agent of the present invention is usually added in an amount of 10 parts by weight or less with respect to 100 parts by weight of the resin to be colored so as to obtain a concentration.

[0026]

EXAMPLES The present invention will now be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and has a wide range of applications. All parts and percentages in the examples and comparative examples are based on weight.

Examples 1, 2 and 3 and Comparative Examples 1 and 2 Phthalocyanine blue (monochloro α type) pigments shown in Table 1 and low molecular weight olefin resins were mixed in a blending ratio (parts) shown in Table 1 with a high speed mixer. After that, the mixture was heated and melted and kneaded with a pressure kneader, and subsequently, the kneaded material finely ground with a three-roll mill was crushed with a crusher to obtain an irregular-shaped granular material having good pigment dispersion. This granular material is shown in Table 1.
The ethylene-α-olefin copolymer described or an ethylene-based resin as a comparative example was mixed at the compounding ratios shown in Table 1, and melt-kneaded with a single-screw extruder (L / D = 27) to form a strand. Extrude, length 2-3 with pelletizer
mm masterbatch color pellets were processed into 100 parts by weight. The obtained pellets are MF showing melt fluidity
R measurement (130 ° C., load 2.16 Kg) was performed, and at the same time, an injection molding color unevenness evaluation test was performed.

The results are shown in Table 1, but the masterbatch color of the composition of the present invention showed no color unevenness. The injection molding color unevenness evaluation test method is as follows. Injection molding color unevenness evaluation test: Master batch color is made of highly crystalline polypropylene (MFR = 30 (230 ° C, load 2.16K
g): Stereoregularity 99%) at the dilution rate (%) shown in Table 1 and mixed, and then the mixture is fitted with a full flight screw (L / D
= 20) with an injection molding machine with a mold clamping of 60 tons and a molding temperature of 210 ° C and a back pressure of 5 kg / cm ^{2 with a} direct gate disk mold (diameter 100 m
m, thickness 2mm).

Color unevenness is evaluated based on the state of occurrence of color streaks recognized on the disc, and the evaluation standard is 5 levels. Evaluation Criteria 1: There are no color streaks. 2: There is a slight color streak. 3: There are small color streaks. 4: There are large color streaks in places. 5: There is a large color streak on the entire surface.

[0030]

[Table 1]

Details of the blended raw materials in Table 1 are as follows. EAO-A: ethylene-propylene copolymer MFR (230 ° C, load 2.16Kg) = 8.6gr / 10min ethylene / propylene ratio 75:25 EAO-B: ethylene-butene-1 copolymer MFR (190 ° C, load 2.16Kg) = 70gr / 10min Ethylene / Butene-1 ratio 80:20 Polyethylene resin-A: Low density polyethylene MFR (190 ° C, load 2.16Kg) = 50gr / 10min Polyethylene resin-B: High density polyethylene MFR (190 ℃, load 2.16Kg) = 40gr / 10min Low molecular weight olefin resin: Low molecular weight polyethylene wax Molecular weight (Mn) = 5000, viscosity (CPS: 140 ° C) = 3000, softening point = 11
1 ° C

Examples 4, 5 and 6 and Comparative Examples 3, 4 and 5 furnace carbon black having a primary particle size of 19 mμ (oil absorption = 47 DBPml / 100gr, PH = 9) and low molecular weight olefin resins shown in Table 2. And an ethylene-α-olefin copolymer shown in Table 2 or a propylene-based resin as a comparative example at a compounding ratio (parts) shown in Table 1 were mixed in a high-speed mixer, melt-kneaded in a Banbury mixer, and taken out. Is processed into a sheet with two rolls and a square pelletizer is used to make a 3-5 mm square masterbatch color pellet 10
Processed to 0 parts by weight. The obtained pellets were subjected to MFR measurement (160 ° C., 190 ° C. load 2.16 Kg) showing melt fluidity and subjected to injection molding color unevenness evaluation test as in Examples 1 and 2.

The injection molding color unevenness evaluation test method was carried out by using polypropylene (MFR = 4 gr / 10 min, 230 ° C. load 2.16 kg: instead of the highly crystalline polypropylene described in Examples 1 and 2).
Stereoregularity of 92%) and 80 parts of talc (average particle size = 2.
(3 μm) 20 parts were extruded (barrel temperature: 230 ° C.) to obtain white pellets.

The results are shown in Table 2, but the masterbatch color of the composition of the present invention showed no color unevenness as compared with the case of using polypropylene or the case of using no low molecular weight ethylene resin.

[0035]

[Table 2]

Details of the blended raw materials in Table 2 are as follows. EAO-C: ethylene / propylene / ethylidene norbornene terpolymer Mooney viscosity (ML1 + 4,125 ° C.) = 26 ethylene / propylene / ethylidene norbornene ratio = 74
/ 3/23 EAO-D: propylene / butene-1 copolymer MFR (230 ° C., load 2.16 Kg) = 20 gr / 10 min Propylene / butene-1 ratio = 80/20 EAO-E: ethylene / propylene copolymer MFR ( 230 ° C, load 2.16Kg) = 20gr / 10min Ethylene / propylene ratio = 20/80 Propylene resin-A: polypropylene block copolymer MFR (230 ° C, load 2.16Kg) = 50gr / 10min Propylene resin-B: polypropylene (Homopolymer) MFR (230 ℃, load 2.16Kg) = 40gr / 10min Low molecular weight olefin resin: acid-modified low molecular weight polyethylene Molecular weight (viscosity method) = 1500, viscosity (CPS: 140 ℃) = 150 Acid value (KOHmg / g) = 60, softening point (° C.) = 108

Examples 7, 8 and 9 and Comparative Examples 6, 7 and 8 Ultramarine blue (ultraviolet: particle diameter 0.7 μm) shown in Table 3
m) and titanium oxide (particle diameter 0.18 μm) and primary particle diameter 18
μm furnace carbon black (oil absorption = 47 DBP m
l / 100 gr, PH = 9) and ethylene-α olefin copolymer or ethylene-based resin or propylene-based resin and low molecular weight olefin-based resin or metal soap or both are mixed in a mixing ratio shown in Table 3 with a high speed mixer. Then, the mixture was heated and kneaded by a co-rotating twin-screw extruder (L / D = 35), and the extrudate in the form of a strand was processed by a pelletizer into cylindrical master batch pellets having a length of 2 to 3 mm. The obtained pellets were subjected to MFR measurement (140 ° C., load 2.16 Kg) showing melt flowability and subjected to injection molding color unevenness evaluation test as in Examples 1 and 2.

The injection molding color unevenness evaluation test method was carried out by using a highly crystalline polypropylene block copolymer {MFR = 30 instead of the highly crystalline polypropylene described in Examples 1 and 2.
gr / 10min (230 ℃, load 2.16Kg), stereoregularity 99%} 7
0 parts and ethylene-butene copolymer {MFR = 4 gr / 10 min
(230 ℃, load 2.16Kg)} 20 parts and talc (average particle size = 2.
The same procedure as in Examples 1 and 2 was repeated, except that 10 parts of 3 μm) was extruded (barrel temperature: 230 ° C.) to obtain white pellets.

Table 4 shows the results of the examples and comparative examples. As shown in the table, compared with those using ethylene resin and propylene resin or those without low molecular weight polyethylene, The masterbatch color of the composition of the present invention had no color unevenness.

[0040]

[Table 3]

[0041]

[Table 4]

Details of the blended raw materials in Table 3 are as follows. EAO-F: ethylene-propylene copolymer Mooney viscosity (ML1 + 4,125 ° C.) = 52 ethylene / propylene ratio 55:45 EAO-G: propylene-butene-1 copolymer viscosity (1
90 ℃, CPS) = 1500 Propylene / Butene-1 ratio 90:10 Polyethylene resin-C: Low density polyethylene MFR (190 ℃, load 2.16Kg) = 70 Polypropylene resin-C: Polypropylene block copolymer MFR (230 ℃, load 2.16Kgg) = 80 Low molecular weight olefin resin: High oxidation type low molecular weight polyethylene wax Molecular weight (viscosity method) = 3200, viscosity (140 ° C, CPS) = 55
0, acid value (KOHmg / gr) = 20

[0043]

EFFECTS OF THE INVENTION When a low molecular weight olefin resin is combined with an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer and used as a vehicle resin for a masterbatch color, injection molding, extrusion molding, or hollow molding of polypropylene is carried out. Occasionally, since the distributability of the coloring component is excellent, it is possible to prevent the occurrence of color unevenness and color streaks, and improve the product appearance and moldability.

As a result, since the pigment as a coloring component in the colorant can be made to have a high concentration, the amount of the colorant used in the color molding is reduced, the coloring cost is reduced and the strength of the molded product is prevented from being lowered, and the moldability is improved. By doing so, the molding cost can be significantly reduced.

Claims (7)

[Claims] 1. A colorant composition for polypropylene comprising a carrier resin comprising an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer and a low molecular weight olefin resin, and a pigment. 2. The colorant composition according to claim 1, wherein the ethylene-α-olefin copolymer is an ethylene-propylene copolymer, and the propylene content thereof is 3 to 95% by weight. 3. The colorant composition according to claim 1, wherein the ethylene-α-olefin copolymer is an ethylene-butene-1 copolymer, and the butene-1 content thereof is 3 to 95% by weight. 4. A propylene-α olefin copolymer,
A propylene-butene-1 copolymer, the butene-
The colorant composition according to claim 1, wherein the content of 1 is 3 to 95% by weight. 5. 1 to 70% by weight of pigment and 30 carrier resins
The ratio of the ethylene-α-olefin copolymer or the propylene-α-olefin copolymer and the low molecular weight olefin resin in the simple substance resin is in the range of 1: 4 to 4: 1. 4. The colorant composition according to any one of 4. 6. The colorant composition according to claim 1, which is in a granular form. 7. The colorant composition according to claim 1, which is for a polypropylene containing a filler or for a highly crystalline polypropylene.