JPH0419264B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to the coloring of various plastics, and relates to a colored resin composition containing a highly uniform coloring agent. (Prior Art) Plastic coloring methods can be broadly classified into dry coloring, colored pellet method, and color masterbatch method. Among these, the color master batch method has the following advantages: (1) excellent pigment dispersibility, (2) high pigment concentration, (3) easy handling, (4)
Coloring has many advantages, including no scattering or contamination, (5) dilution to any desired concentration, (6) convenient measurement, and (7) easy storage. It is an extremely advantageous method within the law,
In particular, it occupies a large position in the coloring of polyolefin resins. The resin component for the masterbatch must have good compatibility with the matrix resin used, and it is also necessary to fill and mix the colorant uniformly at a high concentration. Furthermore, since it is necessary not to greatly deviate between the fluidity levels of the masterbatch and matrix resin, it is better to have a crystalline material with a low melting point and an amorphous material with a low glass transition point, and both have a somewhat low melt viscosity. Preferably. Specifically, for example, in the case of polyolefin, polyethylene wax, low density polyethylene, linear low density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer (EVA)
etc. are representative examples. On the other hand, when coloring styrenic resins, i.e., polystyrene (PS), impact-resistant polystyrene (HIPS), acrylonitrile-butadiene-styrene copolymer (ABS), polycarbonate, modified polyphenylene oxide (modified
The main methods for coloring engineering resins such as PPO), polysulfonate, polyethylene terephthalate (PET), and polybutylene terephthalate (PBT) are the dry color method or the colored pellet method, and the color master batch method is rarely used. Not adopted. (Problems to be solved by the invention) Styrene resins and the aforementioned engineering resins have poor pigment dispersibility compared to polyolefin resins, and even in dry color methods and colored pellet methods, pigments used in There are restrictions on the type and concentration, and the pigment dispersant used to improve the dispersion of pigments can stain the surface of colored molded products and reduce the physical properties. The reality is that the desired colored molded product cannot be obtained unless the process is strictly controlled.
Furthermore, the reason why the color masterbatch method is not widely adopted is that a suitable resin component for masterbatch that satisfies the various requirements of the color masterbatch method described above has not been obtained. For example, a color masterbatch containing a high concentration of pigment based on a mixture of polyethylene wax and polyethylene or EVA has excellent manufacturability and is extremely useful for polyolefin resin. When applied to styrene resins or engineering resins, the dispersibility of the masterbatch is poor due to poor compatibility between the masterbatch resin components and these resins, resulting in poor appearance due to uneven coloring and flow marks on the molded product. and deteriorate the mechanical properties of the molded product. When using styrene resin itself as a resin for masterbatch, there are the following problems. In other words, the kneading properties of the colorant are extremely poor due to the high melt viscosity of the polymer (the melt flow index value according to JIS-K6871 is 30 g/10 min for polystyrene and 8 g/10 min for ABS).
It's a minute. ) Therefore, depending on the type of pigment, it is often impossible to increase the loading amount, and if you try to forcibly increase the concentration of the masterbatch, the dispersibility of the pigment will be extremely reduced. Attempts have also been made to use low molecular weight polystyrene or styrene-grafted polyolefin wax as a pigment dispersant in the dry color method or colored pellet method, or as a masterbatch resin in the color masterbatch method. When these low molecular weight polymers are used as dispersants in the colored pellet method, their low melt viscosity often impedes kneading workability with styrenic resins and engineering resins. Particularly when applied to engineering resins with high melting points or high glass transition points, the set temperature of the kneading extruder is high and the viscosity decreases near the feed hopper opening, causing kneading troubles or even worsening pigment dispersibility. Therefore, special supply methods must be considered. Also,
When these low molecular weight polymers are used as resins for color master batches, when the pigment concentration becomes high, the melt viscosity is too small, making it difficult to disperse pigment particles finely and uniformly (shear stress during kneading In addition, when manufacturing the masterbatch, strand extrusion using a normal extruder cannot be applied due to lack of viscoelasticity, so it has to be prepared using a batch-type kneader, so the shape of the masterbatch is flaky. Become. Flake-like master batches often cause problems during the actual coloring and molding process, as they interfere with smooth transportation through the hopper of the molding machine and the transport pipe. (Objectives of the Invention) The present invention has been made for the purpose of supplying a colored molded product or a coloring agent masterbatch that does not have such drawbacks, and by using a specific resin component,
To provide a colored resin composition that has good dispersibility by kneading a colorant and can be made into a highly concentrated masterbatch, and the resulting molded product has excellent quality (appearance, mechanical properties, etc.) . (Means for Solving the Problems) That is, the present invention provides (A) a melt flow index (MFR) of 0.1 to 400 g/10 min for graft polymerization of an α-olefin polymer resin and an aromatic vinyl monomer. Modified resin with aromatic vinyl monomer unit content of 5 to 70% by weight obtained by subjecting to 100 to 70% by weight
20% by weight and (B) a resin component consisting of 0 to 80% by weight of α-olefin or styrene polymer resin
This is a uniformly colored resin composition characterized by comprising: 100 parts by weight, and 3 to 150 parts by weight of (C) colorant. Since the composition of the present invention is excellent in the above points,
It is also effective as a colorant masterbatch for various matrix resins. (Action) The above component (A) used in the present invention has an MFR of 0.1 to
400g/10min, preferably 5-200g/10min α-
It is obtained by subjecting an olefin polymer resin and an aromatic vinyl monomer to graft polymerization conditions,
The modified resin has an aromatic vinyl monomer unit content of 5 to 70% by weight, preferably 25 to 70% by weight. MFR here is defined by JIS-K6758 (propylene-based polymers) or JIS-K6760 (ethylene-based polymers), and is 230°C for propylene-based polymers and 190°C for ethylene-based polymers. This is the value measured at When an α-olefin polymer with an MFR of less than 0.1 g/10 minutes is used, the extrusion torque of the resin increases and shear heat generation increases, making it difficult to fill the colorant at a high concentration. Moreover, when it is larger than 400g/10 minutes, the kneading workability with the pigment is poor, and it becomes impossible to extrude the strands from the extruder to granulate the masterbatch, and it also becomes impossible to uniformly disperse the masterbatch into the matrix resin and to form the resulting molding. The mechanical strength of the product deteriorates. Aromatic vinyl monomer unit content is 5
If it is less than 70% by weight, no improvement in compatibility with different types of matrix resins can be expected, and if it exceeds 70% by weight, it is not suitable for uniformly kneading the colorant at a high concentration. Here, the α-olefin polymer resin is a crystalline polypropylene-based polymer such as propylene homopolymer, other α-olefin mainly composed of propylene, or a copolymer with ethylene or with an unsaturated organic acid or its derivative. A group of resins are preferably mentioned. Specifically, representative examples include isotactic polypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-butene-1 random copolymer, and maleic anhydride-modified polypropylene.
Furthermore, the following ethylene polymers are preferably mentioned. That is, in addition to high-, medium-, and low-density ethylene polymers, the majority of ethylene and other monomers, such as vinyl esters (vinyl acetate, etc.), unsaturated organic acids or their derivatives (acrylic acid, methacrylic acid, maleic anhydride, , methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, metal salts of acrylic acid, metal salts of methacrylic acid, etc.), α-olefins (propylene, butene-1, pentene-1, 4-methylpentene-1, hexene block, random or graft copolymers with heptene-1, heptene-1, octene-1, etc.) are suitable. Among these, propylene-ethylene random copolymer, propylene-butene-1 copolymer,
Low density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), etc. are preferred. In addition, as an aromatic vinyl monomer, the general formula

[Formula] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₂ to _{R 6} are a hydrogen atom, a chlorine atom, or an alkyl group having 1 to 4 carbon atoms, respectively.) Monomers such as styrene, nuclear substituted styrenes (eg, methylstyrene, isopropylstyrene, chlorstyrene), alpha-substituted styrenes (eg, alpha-methylstyrene, alpha-ethylstyrene), and the like. Mixed systems such as styrene and acrylic ester, styrene and methacrylic ester, and styrene and acrylonitrile are also applicable. Among these, when styrene is used, it is possible to reduce the molecular weight of the polystyrene by-produced in addition to the styrene graft chains by selecting polymerization conditions, which is preferable. Further, it is preferable to use styrene together with a long chain acrylate such as n-butyl acrylate or 2-ethylhexyl acrylate, since the glass transition point of the modified resin can be lowered. As the graft polymerization conditions, conventional methods such as melt grafting, solution grafting, suspension grafting, radiation grafting, and gas phase grafting can be employed, but preferably, for example, the following method can be used. That is, α-olefin polymer particles 30 to 95
wt%, aromatic vinyl monomer 70-5 wt% and decomposition temperature 50-50 to obtain a half-life of 10 hours.
Heating an aqueous suspension containing 0.01 to 5 parts by weight of a radical polymerization initiator at 150°C based on 100 parts by weight of the aromatic vinyl monomer under conditions that do not substantially cause decomposition of the initiator, The aromatic vinyl monomer is impregnated into the alpha-olefinic polymer particles until the amount of free aromatic vinyl monomer is less than 20% by weight, and the temperature of the aqueous suspension is then raised to absorb the aromatic Complete the polymerization of vinyl monomer. Among the modified resins thus obtained, preferred are styrene-modified EVA, styrene-modified low-density polyethylene, and styrene-modified propylene-ethylene random copolymer. Next, the α-olefin polymer resin which is the component (B) used in the present invention can be appropriately selected from the above-mentioned α-olefin polymer resins. In addition, styrenic polymer resin has at least a structural unit represented by the following general formula in the resin.
twenty five

[Formula] is a resin containing at least % by weight. (Here, R is a hydrogen atom or a methyl group, Z
represents a halogen atom or a methyl group, and p is 0 or an integer of 1 to 3. ) Specific examples include homopolymers and copolymers of styrene and its derivatives, such as polystyrene rubber-modified polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, and the like. Blends of these resins with styrene-conjugated diene block copolymer rubber and hydrogenated products thereof are also applicable. (B) component α
- Olefin polymer resin and styrene polymer resin can be used in combination. In addition, as the coloring agent of the above component (C) used in the present invention, raw pigments conventionally used in color molding of thermoplastic resins and processed pigments consisting of pigments, dispersants, and other additive components are used. Can be mentioned. Specific examples of pigments include titanium white (rutile), titanium white (anatase), titanium yellow, cadmi yellow, isoindolinone yellow, polyazo yellow, quinophthalone yellow,
Phthalocyanine green, phthalocyanine blue, ultramarine blue, cobalt blue, polyazo brown,
Organic and inorganic pigments include red red, polyazol, perylene, quinacridone, aniline black, carban black, etc. The blending ratio of each component used in the present invention is the above (A) modified resin 100 to 20% by weight, preferably 40% by weight or more, and (B) α-olefin or styrene polymer resin 0 to 80% by weight. , preferably 60% by weight or less of the resin component, (C) colorant 3
~150 parts by weight, preferably 5 to 100 parts by weight. If the modified resin is less than 20% by weight, the compatibility with a different matrix will be unsatisfactory, and if the colorant exceeds 150 parts by weight, sufficient melt-kneading with the resin will be impossible, making it unsuitable as a masterbatch. In the present invention, other components such as an antioxidant, a weather resistance improver, an antistatic agent, and a plasticizer can also be contained. As an embodiment of the present invention, for example, the following method can be applied. (1) A method of coloring and molding various matrix resins using a colorant masterbatch pellet consisting of the above (A) + (B) + (C). The matrix is PS, ABS,
Polycarbonate, modified PPO, PPO, acrylonitrile-styrene resin, 6 nylon,
Particularly good results are obtained with nylon 6.6, PBT and PET. (2) A colored pellet method consisting of (A) + (B) + (C) + the above matrix resin. (3) A method of coloring and molding using an existing color master batch for α-olefin polymers (base resin is α-olefin polymer), components (A) + (B), and matrix resin. The composition of the present invention, for example, the masterbatch composition of method (1) above, is thoroughly melt blended and granulated using a high shear kneader such as a Banbury mixer, a roll kneader, or a twin screw extruder. A twin-screw extruder is particularly preferred since masterbatch pellets can be obtained in one step. (Example) Example 1 MFR measured by JIS-K6760 is 80g/10min
A modified polymer obtained by grafting 50% by weight of styrene monomer onto EVA has an average particle size of approximately 80%.
25 parts by weight of a red pigment consisting of 1:1:1 of quinacridone:perylene red:magnesium stearate (dispersant) was thoroughly mixed with 100 parts by weight of powder frozen and ground into microns using a super mixer. This powder mixture was melt-kneaded in a co-rotating twin-screw extruder to obtain granulated pellets (masterbatch). The kneading and extrusion conditions were a cylinder temperature of 130°C to 150°C, a die temperature of 150°C, and a screw rotation speed of 200 rpm. As a result of the experiment, there was no rise in cylinder temperature or overload of the motor (screw motor current was 8 to 10A, normal operating range).
Masterbatch pellets with uniform particle size could be produced by stably extruding them in the form of strands. Comparative Example 1 25 parts by weight of the same red pigment used in Example 1 was added to 100 parts by weight of powder obtained by freezing and pulverizing polystyrene with an MFR of 30 g/10 minutes to an average particle size of approximately 80 microns as measured by JIS-K6871 using a super mixer. An attempt was made to produce masterbatch pellets under the same conditions as in Example 1 by dry blending. results of the experiment,
As the screw torque is large and the resin temperature rises, the viscosity decreases rapidly and the dispersibility of the pigment becomes poor.
It was difficult to collect the pellets in the form of strands and turn them into pellets. Example 2 MFR measured by JIS-K6760 is 150g/10min
60% by weight of a powder obtained by freezing and pulverizing a modified polymer obtained by graft polymerizing EVA with 35% by weight of styrene monomer and 15% by weight of 2-ethylhexyl acrylate to an average particle size of about 80 microns;
40 parts by weight of the same red pigment used in Example 1 was added to 100 parts by weight of a dry blend of MFR 60g/10 minutes and 40% by weight of low-density PE powder with an average particle size of about 150 microns in a super mixer. The mixture was mixed to produce masterbatch pellets under the same conditions as in Example 1. The stability of the extruded strand is also good,
A masterbatch in which a high concentration of pigment was well dispersed was obtained. Comparative Example 2 60% by weight of the same polystyrene powder used in Comparative Example 1, MFR 60g/10min, average particle size approximately 150
Micron low density polyethylene (PE) powder
An attempt was made to produce a masterbatch by adding 20 parts by weight of the same red pigment used in Example 1 to 100 parts by weight of a dry blend of 40% by weight in a super mixer. The manufacturing conditions were a cylinder temperature of 150°C to 180°C, a die temperature of 180°C, and a screw rotation speed of 200 rpm. Compared to Comparative Example 1, the screw torque is slightly smaller due to the blending effect of low-density PE, and the rise in resin temperature is relatively suppressed, but the blending compatibility of polystyrene and low-density PE is poor, so the strand It was not possible to obtain uniform masterbatch pellets in which the pigment was sufficiently evenly dispersed due to severe buildup of eye stains around the exit of the die and partial fibrillation (due to delamination) of the extruded strands. . Example 3 A modified polymer obtained by graft polymerizing 50% by weight of styrene monomer to a propylene-ethylene random copolymer with an MFR of 6 g/10 minutes as measured by JIS-K6758 was pulverized to an average particle size of approximately 80 microns. Master batch pellets were produced in the same manner as in Example 1 by adding 20 parts by weight of the same red pigment as used in Example 1 to 100 parts by weight of the powder. The manufacturing conditions were a cylinder temperature of 180°C to 220°C, a die temperature of 220°C, and a screw rotation speed of 200 rpm. There is little variation in the amperage of the screw motor, and the strand take-up condition is stable.
A masterbatch with a good pellet shape was obtained. Application example 1 HIPS (Dialex HT manufactured by Mitsubishi Monsanto)
-88) For 100 parts by weight, add 2.5 or 5 parts by weight of the masterbatch with a pigment concentration of 25 parts by weight obtained in Example 1.
Injection molding of the material to which parts by weight were added was attempted. Using a 6oz screw in-line injection molding machine, the molding conditions were a molding temperature of 220℃ and a back pressure of 6Kg/ ^cm2 .
Kg/cm ² , injection pressure 600Kg/cm ² , injection speed 2sec/
shot, and the mold temperature was 76°C. The obtained molded article had a good appearance without uneven pigment dispersion or flow marks. In addition, a part of the molded product was cut out, a 0.1 mm film was made by press molding, and the pigment dispersibility was observed using an optical microscope, but almost no large pigment agglomerates (75 microns or more) were observed. It was found that it exhibited good dispersibility. Table 1 shows the physical properties of the injection molded product.

[Table] Application example 2 The masterbatch obtained in Example 1 and the masterbatch obtained in Example 3 (pigment concentration 20 parts by weight ) were added in an amount of 5 and 2.5 parts by weight, respectively. A 6oz screw in-line injection molding machine was used, and the molding conditions were a molding temperature of 270°C, an injection pressure of 1000 kg/cm ² , an injection speed of 2 sec/shot, and a mold temperature of 80°C. The obtained molded article had a good appearance without uneven pigment dispersion or flow marks. Table 2 shows the physical properties of the injection molded product.

[Table] Application example 3 Injection molding of a material was attempted by adding 2 parts by weight of the masterbatch with a pigment concentration of 40 parts by weight obtained in Example 2 to 100 parts by weight of polycarbonate resin (Iupilon C-3000 manufactured by Mitsubishi Gas Chemical Co., Ltd.). . As in Application Examples 1 and 2, the appearance and physical properties of the molded product were measured. Especially in terms of appearance, it was found that the base resin of the masterbatch has good fluidity and has the effect of lowering the viscosity of the polycarbonate matrix, making it possible to obtain molded products with high gloss even at relatively low mold temperatures. . The molding conditions were a molding temperature of 270°C, an injection pressure of 1000 Kg/cm ² , an injection speed of 2 sec/shot, and a mold temperature of 70°C. Table 3 shows the physical properties of the injection molded product.

[Table] Example 4 Modified polymer powder in Example 3 5% by weight Red pigment in Example 1 1.5 parts by weight HIPS (Dialex HT- manufactured by Mitsubishi Monsanto)
88) 95% by weight was thoroughly mixed in a super mixer. This mixture was melt-kneaded using a single screw extruder (40 m/m diameter, L/D=22) to obtain color pellets. The kneading and extrusion conditions were a cylinder temperature of 220°C, a die temperature of 215°C, and a screw rotation speed of 60 rpm. Using the obtained color pellets, injection molding was carried out in the same manner as in Application Example 1. The obtained molded product had a good appearance with no uneven pigment dispersion or flow marks. In addition, the physical properties of the injection molded product are good,
It was found that a product with an excellent balance of physical properties and appearance could be obtained. Table 4 shows the physical properties of the injection molded product. Example 5 Low density polyethylene (MFR45g/10 minutes)
50 parts by weight of a color masterbatch for polyolefin resin consisting of 100 parts by weight of a gray pigment consisting of titanium white/carbon black, 50 parts by weight of magnesium stearate (dispersant) 10 parts by weight, and 50 parts by weight of the modified polymer in Example 2. % and was melt-kneaded in a co-rotating twin-screw extruder to obtain granulated pellets. Injection molding of a material prepared by adding 2 parts by weight of this colored pellet to 100 parts by weight of polycarbonate (Iupilon C-3000 manufactured by Mitsubishi Gas Chemical Co., Ltd.) was attempted. Molding conditions are molding temperature 270℃ and injection pressure.
1000Kg/cm ² , injection speed 2sec/shot, mold temperature 70℃
And so. The obtained molded article has good pigment dispersion and an excellent appearance. Table 4 shows the physical properties of the injection molded product.

[Table] (Effects of the Invention) The colorant of the present invention has good dispersibility, so it can be used as a dispersant or as a high-concentration masterbatch, and the colorant has good compatibility with the matrix resin, so the molded product obtained It has the effect of providing excellent appearance, mechanical strength, etc.

Claims (1)

[Claims] 1 (A) Melt flow index is 0.1 to 400g/
100 to 20% by weight of a modified resin with an aromatic vinyl monomer unit content of 5 to 70% by weight obtained by subjecting 10 minutes of α-olefin polymer resin and an aromatic vinyl monomer to graft polymerization conditions; B) 100 parts by weight of a resin component consisting of 0-80% by weight of an α-olefin or styrene polymer resin, and (C) 3-150 parts by weight of a coloring agent consisting of an organic or inorganic pigment. Uniformly colored resin composition.