JP5223165B2 - Colored resin composition for polypropylene resin and colored resin molded product - Google Patents

Description

  The present invention relates to a colored resin molded product having no color separation and good appearance. Furthermore, it is related with the colored resin composition useful in order to obtain this molded article.

In recent years, many polypropylene-based materials have been used for automobile parts materials, packaging container materials, home appliance parts materials, and the like. This polypropylene-based material has good dimensional stability and impact resistance, and generally a material based on an ethylene / propylene-block copolymer is used.
However, this colored molded product of plastic containing polypropylene often has a problem of poor appearance of the molded product due to color separation caused by poor dispersion of pigment. The color separation tends to become remarkable as the molding speed increases.

  In addition, colorants of various pigment forms are used for coloring plastics such as polypropylene materials. Among these colorants, master batches have become the mainstream of colorants because of their excellent performance (for example, non-contamination, automatic meterability, transportability). When diluting the masterbatch into the resin, the problem is the dispersibility (peptization) of the high-concentration pigment in the masterbatch to the molded product. If the distribution is poor, color separation occurs on the surface of the molded product.

For the above problem, there is a method of using a polyolefin wax produced using a metallocene catalyst for the purpose of improving the dispersion state of the pigment in polypropylene (Patent Document 1).
In addition, for the problem of uneven color of highly fluid ethylene / propylene copolymer colored molded products, the base resin of the masterbatch is composed of a specific ratio of polypropylene resin and linear low density polyethylene, and this is combined with wax and By using a master batch obtained by blending a lubricant selected from a metal soap and a pigment, there is a technique for obtaining a molded product having no color unevenness without impairing the appearance of the molded product (Patent Document 2).
However, under high-speed molding conditions such as high-speed extrusion molding and compression molding, the appearance of molding is inevitably generated due to the color separation of the pigment even when the above-described technique is used.

Special table 2003-525329 gazette Japanese Patent Laid-Open No. 10-72527

  An object of the present invention is to provide a colored resin molded article excellent in dispersibility of pigments, having no color separation and uneven color, and having a good appearance, and a colored resin composition useful for obtaining the same.

A first invention of the present invention is a colored resin composition for a polypropylene resin (D) comprising a thermoplastic resin (A), a pigment (B), and a polypropylene wax (C),
The interface free energy between the thermoplastic resin (A) and the pigment (B) is less than 40 mN / m,
A colored resin composition for a polypropylene resin (D) having an interface free energy of 40 mN / m or less between the pigment (B) and the polypropylene resin (D).

2nd invention is the coloring resin composition for polypropylene resins (D) as described in 1st invention whose dropping point of polypropylene wax ( C ) is 60 to 160 degreeC.

3rd invention is the colored resin composition for polypropylene resins (D) as described in 1st or 2nd invention whose density of polypropylene wax ( C ) is 0.87-0.92 g / cm < ³ >. .

4th invention is the colored resin composition for polypropylene resins (D) in any one of 1st-3rd invention whose viscosity (170 degreeC) of polypropylene wax ( C ) is 1-10000 mPa * s. .

The fifth invention is the colored resin composition for polypropylene resin (D) according to any one of the first to fourth inventions, wherein the polypropylene wax ( C ) is a metallocene polypropylene wax.

  The sixth invention is the colorant composition for polypropylene resin (D) according to any one of the first to fifth inventions, further comprising a slip agent (E).

  7th invention is the colored resin composition for polypropylene resins (D) as described in 6th invention whose slip agent (E) is fatty acid amide.

  An eighth invention is a colored resin molded article obtained by using the colored resin composition for polypropylene resin (D) according to any one of the first to seventh inventions and the polypropylene resin (D).

  A ninth invention is the colored resin molded product according to the eighth invention, which is a high-speed compression molded product.

The colored resin composition for polypropylene resin (D) of the present invention includes a thermoplastic resin (A), a pigment (B), and a polypropylene wax (C), and includes the thermoplastic resin (A) and the pigment (B). The interface free energy is less than 40 mN / m,
Since the interfacial free energy between the pigment (B) and the polypropylene resin (D) is 40 mN / m or less, the dispersibility of the pigment (B) is good.

Moreover, since the dropping point of polypropylene wax ( C ) is 60 ° C to 160 ° C, the processability is good.

Further, since the density of the polypropylene wax ( C ) is 0.87 to 0.92 g / cm ^{3, the} processability and the pigment filling property are good.

Moreover, since the viscosity (170 degreeC) of polypropylene wax ( C ) is 1-10000 mPa * s, wetting with a processability, a pigment, etc. is favorable.

Also, since the polypropylene wax ( C ) is a metallocene polypropylene wax, the processability is good.

  Furthermore, since a slip agent (E) is contained, workability is favorable.

  Moreover, since the slip agent (E) is a fatty acid amide, the processability is better.

  Since the colored resin molded article of the present invention is a colored resin molded article obtained by using any one of the above colored resin composition for polypropylene resin (D) and polypropylene resin (D), distribution of pigment (B) Good color and color separation can be suppressed. Therefore, there is no color unevenness and the appearance is good.

  Since the colored resin molded product of the present invention is a colored resin molded product obtained by using any one of the above-described colored resin composition for polypropylene resin (D) and polypropylene resin (D), it may be molded at high speed. Good appearance with no color unevenness.

<Thermoplastic resin (A)>
Examples of the thermoplastic resin (A) used in the present invention include polyolefin resins such as polyethylene resins and polypropylene resins, polystyrene resins, polyphenylene ether resins, acrylonitrile-butadiene-styrene copolymer resins, polycarbonate resins, and polyamide resins. , Polyacetal resins, polyester resins, polyvinyl chloride resins, polymethyl methacrylate resins, polyetherimide resins, and mixtures thereof.

Since the coloring target resin (diluted resin) of the coloring resin composition of the present invention is a polypropylene resin, a polyolefin resin having good compatibility is preferable.
Polyolefin resins include crystalline or amorphous polypropylene, polybutene-1, poly-4-methylpentene, low or high density polyethylene, ethylene-propylene random, block or graft copolymers, α-olefins and ethylene Or a copolymer of propylene, an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-acrylic acid copolymer, and the like, Two or more kinds can be used.

  In particular, crystalline or amorphous polypropylene, ethylene-propylene random, block or graft copolymers are preferred. A propylene-ethylene block copolymer is preferably used. Among these, polypropylene is particularly preferred because it is inexpensive and has a small specific gravity, so that the molded product can be reduced in weight.

  The form of the thermoplastic resin (A) is not particularly limited, but a powder form is preferable in consideration of dispersibility of the pigment (B) and the like.

<Pigment (B)>
As the pigment (B) used in the present invention, known organic pigments and inorganic pigments conventionally used for coloring printing inks, paints, or thermoplastic resins can be used.
Organic pigments include azo lakes such as azo lake, hansa, benzimidazolone, diarylide, pyrazolone, yellow and red; phthalocyanine, quinacridone, perylene, perinone, dioxazine, anthraquinone, iso Examples thereof include polycyclic pigments such as indolinone and aniline black.
Examples of inorganic pigments include inorganic pigments such as titanium oxide, titanium yellow, iron oxide, ultramarine blue, cobalt blue, chromium oxide green, yellow lead, cadmium yellow, and cadmium red, and carbon black pigments.

Furthermore, in the present invention, it is necessary that the interface free energy between the pigment (B) and the thermoplastic resin (A) is less than 40 mN / m. Furthermore, 30 mN / m or less is more preferable, and 20 mN / m or less is particularly preferable.
Moreover, the interface free energy of a pigment (B) and a polypropylene resin (D) needs to be 40 mN / m or less, respectively. Furthermore, 30 mN / m or less is more preferable, and 20 mN / m or less is particularly preferable.

  When a plurality of types of pigment (B) are used, the interface free energy with the thermoplastic resin (A) is required to be less than 40 mN / m for each pigment. If at least one is 40 mN / m or more, only the pigment is selectively ejected from the resin or other pigment kneaded material during resin-pigment kneading, causing color separation.

  Furthermore, the interface free energy with the polypropylene resin (D) is required to be 40 mN / m or less for each pigment. When one kind of pigment exceeds 40 mN / m, only the pigment is selectively ejected from the resin or other pigment kneaded material during resin-pigment kneading, causing color separation.

In particular, in the case of producing a toned product using a plurality of types of pigments, the hue of the pigment in the kneaded product and the color of the ejected pigment is different (for example, green and yellow, blue and yellow, red And white)), the ejected pigment colors the molded product non-uniformly, detracting from the value of the molded product.
In order to adjust the interfacial free energy, the pigment may be subjected to a surface treatment.

The interface free energy is a factor representing the affinity between samples, and is calculated from the surface free energy of each sample using the extended Fowkes equation. It shows that the affinity between samples is so high that the value of interface free energy is small.
The surface free energy of each sample is obtained from the Young's equation, Dupre's equation, and extended Fowkes' equation by measuring the contact angle of each sample using a standard solution by the droplet contact angle method. Three types of liquids are required as a standard liquid: a nonpolar liquid, a polar liquid, and a hydrogen bonding liquid. In the present invention, hexadecane is used as the nonpolar liquid, methylene iodide is used as the polar liquid, and water is used as the hydrogen bonding liquid. The measured value was used.

  The content of the pigment (B) in the colored resin composition for polypropylene resin (D) of the present invention is preferably 0.01 to 80% by weight, more preferably 0.1 to 60%, and more preferably 0.1 to 20% by weight. Is particularly preferred. If the amount is less than the above range, a coloring effect cannot be obtained unless a large amount of the colored resin composition for polypropylene resin (D) is used in the production of a molded product. Conversely, if the amount is more than the above range, poor pigment dispersion tends to occur. .

<Polypropylene wax (C)>
The polypropylene wax (C) used in the present invention includes polypropylene, a copolymer of ethylene and propylene (random or block copolymer), and a copolymer of propylene and α-olefin (excluding ethylene or propylene). And waxes such as metallocene polypropylene wax. Alternatively, a wax obtained by thermally decomposing these copolymers may be used.
Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and the like can be mentioned. 1-butene and 1-hexene are preferred.

  A metallocene polypropylene wax refers to a polypropylene wax obtained using a metallocene compound as a polymerization catalyst. The characteristic of this wax is that it is highly monodispersed and has a narrow molecular weight distribution compared to the case where a conventional Ziegler catalyst, Ziegler-Natta catalyst or the like is used. Furthermore, both density and dropping point can be designed to be significantly lower than general-purpose wax made of the same monomer polymerized with a nonmetallocene catalyst, and a wide range of processing conditions and machines can be selected. Furthermore, the metallocene polypropylene wax has a property of high compatibility with the diluted resin and is preferably used.

  The metallocene compound is a general term for compounds in which at least one ligand having a cyclopentadienyl skeleton is coordinated to a tetravalent transition metal such as titanium, zirconium, nickel, palladium, hafnium, niobium, platinum, and the like.

As a ligand having a cyclopentadienyl skeleton, a cyclopentadienyl group; a methylcyclopentadienyl group, an ethylcyclopentadienyl group, an n- or i-propylcyclopentadienyl group, n-, i-, sec -, Tert-butylcyclopentadienyl group, hexylcyclopentadienyl group, alkyl monosubstituted cyclopentadienyl group such as octylcyclopentadienyl group; dimethylcyclopentadienyl group, methylethylcyclopentadienyl group, Alkyl disubstituted cyclopentadienyl groups such as methylpropylcyclopentadienyl group, methylbutylcyclopentadienyl group, methylhexylcyclopentadienyl group, ethylbutylcyclopentadienyl group, ethylhexylcyclopentadienyl group; trimethyl Cyclopentadie Alkyl group, tetramethylcyclopentadienyl group, alkyl polysubstituted cyclopentadienyl group such as pentamethylcyclopentadienyl group; cycloalkyl substituted cyclopentadienyl group such as methylcyclohexylcyclopentadienyl group; indenyl group, Examples include 4,5,6,7-tetrahydroindenyl group and fluorenyl group.

  Examples of ligands other than the ligand having a cyclopentadienyl skeleton include monovalent anion ligands such as base and bromine, divalent anion chelate ligands, hydrocarbon groups, alkoxides, amides, arylamides, aryloxides, phosphides, Examples include aryl phosphide, silyl group, and substituted silyl group. Examples of the hydrocarbon group include those having about 1 to 12 carbon atoms. For example, methyl group, ethyl group, propyl group, butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, hebutyl group, octyl group Alkyl groups such as nonyl group, decyl group, cecil group and 2-ethylhexyl group; cycloalkyl groups such as cyclohexyl group and cyclopentyl group; aryl groups such as phenyl group and tolyl group; aralkyl groups such as benzyl group and neophyll group; Nonylphenyl group etc. are mentioned.

  Specific examples of metallocene compounds coordinated with a ligand having a cyclopentadienyl skeleton include cyclopentadienyl titanium tris (dimethylamide), methylcyclopentadienyl titanium tris (dimethylamide), and bis (cyclopentadiene). Enyl) titanium dichloride, dimethylsilyltetramethylcyclopentadienyl-tert-butylamidozirconium dichloride, dimethylsilyltetramethylcyclopentadienyl-pn-butylphenylamidozirconium dichloride, methylphenylsilyltetramethylcyclopentadienyl- tert-Butylamide Hafnium Dichloride, Dimethylsilyltetramethylcyclopentadienyl-tert-Butylamide Hafnium Dichloride, Indenyl Titanium Tris Dimethylamide), indenyl titanium tris (diethylamide), indenyl titanium bis (di -n- butylamide), indenyl titanium bis (di -n- propyl amide) and the like.

  Such a metallocene compound can be used as a cocatalyst, for example, as a catalyst system to which methylaluminoxane, a boron compound or the like is added. In this case, the ratio of the cocatalyst to the metallocene compound is preferably 1 to 1 million mol times.

The dropping point of polypropylene wax ( C ) is preferably in the range of 60 to 160 ° C. If it is higher than the above range, the dispersible processing machines that can be used are limited, and for example, processing with steam ROLL tends to be difficult. Moreover, when it is lower than the above range, sticky operability tends to deteriorate at room temperature. A range of 80 to 120 ° C. is more preferable.
The dropping point in the present invention is a value measured according to ASTM D 3954.

In addition, the density of the polypropylene wax ( C ) is preferably in the range of 0.87 to 0.92 g / cm ³ from the viewpoint of the drop point and pigment filling.

  In another preferred embodiment, a wax having a viscosity (170 ° C.) in the range of 1 to 10,000 mPa · s, further 1 to 2000 mPa · s, in particular 5 to 1900 mPa · s is selected. When the viscosity is less than 1 mPa · s, handling such as processability tends to be difficult. On the other hand, when the viscosity exceeds 10,000 mPa · s, the wettability with the pigment and the like deteriorates, and the desired dispersibility and mechanical properties tend not to be obtained. In addition, the precision rotational viscometer was used for the measurement of the viscosity in this invention.

  The form of the polypropylene wax (C) is not particularly defined, but a powder form is preferable in consideration of dispersibility of the pigment (B) and the like.

  The content of the polypropylene wax (C) in the colored resin composition for the polypropylene resin (D) of the present invention is preferably 0.01 to 60% by weight, more preferably 0.1 to 50% by weight, and 0.1 to 10%. Weight percent is particularly preferred. If the amount is less than 0.01% by weight, the dispersibility of the pigment is not sufficient. Conversely, if the amount is more than 60% by weight, the physical properties of the colored resin molded product are deteriorated.

<Polypropylene resin (D)>
In the present invention, the polypropylene resin (D) is used as a diluted resin (colored resin) that is mixed with the polypropylene resin (D) coloring resin composition and melt-kneaded and molded during the production of a resin molded product. The same kind as the thermoplastic resin (A) may be used.
The interface free energy between the polypropylene resin (D) and the pigment (B) needs to be 40 mN / m or less.

Examples thereof include a propylene homopolymer, a propylene-α-olefin random copolymer, a propylene-ethylene block copolymer, and a mixture thereof.
Examples of the α-olefin of the propylene-α-olefin random copolymer include α-olefins having 2 or 4 to 8 carbon atoms such as ethylene, butene-1, hexene-1, and octene-1. The content of α-olefin in the propylene-α-olefin random copolymer is preferably 1 to 49% by weight.

  The propylene-ethylene block copolymer is composed of 60 to 95% by weight of a crystalline propylene homopolymer part obtained by homopolymerization of propylene and 40 to 5% by weight of a copolymer part of ethylene and propylene. It is preferable that the ethylene content in the polymerization portion is 10 to 60% by weight.

<Slip agent (E)>
The slip agent (E) used in the present invention is blended as necessary in order to give appropriate slipperiness to the resin molded product. The slip agent (E) is preferably a fatty acid amide. For example, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, oleyl palmitamide, stearyl erucamide and the like can be mentioned.
0.1-30 weight% is preferable and, as for content of the slip agent (E) in the colored resin composition for polypropylene resins of this invention, 1-20 weight% is especially preferable. If the amount is less than the above range, a sufficient slip effect cannot be obtained. On the other hand, if the amount is more than the above range, it is difficult to process the colored resin composition.

<Colored resin composition for polypropylene resin (D)>
The colored resin composition for the polypropylene resin (D) of the present invention is a so-called obtained by mixing and melting and kneading the above components (A) to (C) or the components (A) to (C) and (E). It is a master batch.
As the mixing and melt-kneading method, (B) and (C) may be first mixed and melt-kneaded, and then (A) may be added and further melt-kneaded, or (A) or (B) , (C) may be mixed and melt-kneaded at the same time.
Further, when using a plurality of types (B), first, (B) one type and (C) are mixed and melt-kneaded to prepare a melt-kneaded product, and then a plurality of types (B) (C) melt-kneading. The product may be mixed and melt kneaded again.

<Colored resin molded product>
The colored resin molded product of the present invention can be obtained by diluting the above colored resin composition for polypropylene resin (D) with polypropylene resin (D). The molding method may be any of extrusion molding, injection molding, blow molding and the like. Examples of extrusion molding include compression molding, pipe extrusion molding, laminate molding, T-die molding, inflation molding, and melt spinning.
Among them, high-speed extrusion molding (production speed of about 150 rpm) that is faster than ordinary extrusion molding, compression molding, particularly high-speed compression molding that is about 10 times the molding speed of injection molding (production speed of 500 pieces / minute or more, The structure of the present invention has a remarkable effect at 700-900 / min).

  The present invention will be described in more detail below, but the present invention is not limited to these examples without departing from the technical idea of the present invention. In the following, “parts by weight” is simply referred to as “parts”, and “weight%” is simply referred to as “%”. The resin-pigment interface free energy used in Examples and Comparative Examples is summarized in Table 1.

1. Production of masterbatch (Examples 1 to 4, Comparative Examples 1 to 4)
As shown in Table 2, a yellow pigment and a green pigment were each dispersed and kneaded with a polyolefin wax at a ratio of 1: 1 with steam 3ROLL to obtain a pigment dispersion.
The obtained pigment dispersion, thermoplastic resin, titanium oxide and erucic acid amide were premixed with a Henschel mixer in the ratios shown in Table 2, and then screw diameter 30 mm, L / D (screw diameter / screw length) = 38 to The mixture was supplied to an extruder No. 42 and melt kneaded and extruded under the conditions of a rotational speed of 250 rpm and a set temperature of 180 to 200 ° C. to obtain a colored resin composition.

2. Manufacture of molded products (extrusion molding)
1 part of the masterbatch and 12 parts of polypropylene (propylene-ethylene block copolymer, MFR = 10) as a dilution resin are mixed, and a molding temperature of 160 to 200 ° C. using a T-die film molding machine (manufactured by Toyo Seiki). Then, melt extrusion molding was performed at each of rotation speeds of 50 rpm and 150 rpm to obtain a film-like molded product having a film thickness of 50 μm.

(Compression molding)
1 part of the masterbatch and 12 parts of polypropylene (propylene-ethylene block copolymer, MFR = 10) as a dilution resin are mixed, and a molding temperature of 160 to 200 ° C. is produced using a compression molding machine (manufactured by Toyo Seiki). Melt-extrusion compression molding was performed at a speed of 800 pieces / min to obtain a three-dimensional molded article.

3. Evaluation method (evaluation of appearance of molded product)
The surface of the molded product was visually observed, and appearance defects due to color separation were evaluated according to the following criteria. The evaluation results are shown in Table 4.
○: No color separation △: Some appearance defects due to color separation ×: Many appearance defects due to color separation

  The interface free energy was calculated from the surface free energy of each sample using the extended Fowkes equation. The surface free energy of each sample was determined from the Young's equation, Dupre's equation, and extended Fowkes' equation by measuring the contact angle of each sample using a standard solution by the droplet contact angle method. The standard solution used was hexadecane as a nonpolar liquid, methylene iodide as a polar liquid, and water as a hydrogen bonding liquid.

HDPE: High density polyethylene, MFR = 12
PP: propylene-ethylene block copolymer, MFR = 7
PP-WAX (A): Polypropylene wax (Drip point: 120 ° C., Density: 0.89 g / cm ³ , Viscosity (170 ° C.): 50 mPa · s)
PP-WAX (I): Polypropylene wax (Drip point: 90 ° C., density: 0.88 g / cm ³ , viscosity (170 ° C.): 200 mPa · s)
PP-WAX (U): polypropylene wax (dropping point: 90 ° C., density: 0.88 g / cm ³ , viscosity (170 ° C.): 1800 mPa · s)
PE-WAX (E): Polyethylene wax (Drip point: 105 ° C., Density: 0.92 g / cm ³ , Viscosity (140 ° C.): 1000 mPa · s)
Condensed Azo: Yellow Pigment (CI Pigment Yellow 93)
Disazo: Yellow pigment (CI Pigment Yellow 180)
Phthalocyanine Green: Green pigment (CI Pigment Green 7)
Titanium dioxide: White pigment (CI Pigment WHITE 6)
* The dropping point of WAX was measured according to ASTM D 3954.
* The viscosity of WAX was measured using a Brookfield viscometer for PE-WAX and a precision rotational viscometer for PP-WAX.

Claims (7)

A colored resin composition for compression molding polypropylene resin (D) comprising a thermoplastic resin (A), a pigment (B), a polypropylene wax (C), and a fatty acid amide,
The interface free energy between the thermoplastic resin (A) and the pigment (B) is less than 40 mN / m,
The interface free energy between the pigment (B) and the polypropylene resin (D) is 40 mN / m or less,
A colored resin composition for compression molding polypropylene resin (D) containing 1 to 20% by weight of a fatty acid amide.   The colored resin composition for compression molding polypropylene resin (D) according to claim 1, wherein the dropping point of the polypropylene wax (C) is 60C to 160C. The colored resin composition for compression molding polypropylene resin (D) according to claim 1 or 2, wherein the density of the polypropylene wax (C) is 0.87 to 0.92 g / cm ³ .   The colored resin composition for compression molding polypropylene resin (D) according to any one of claims 1 to 3, wherein the viscosity (170 ° C) of the polypropylene wax (C) is 1 to 10000 mPa · s. The colored resin composition for compression molding polypropylene resin (D) according to any one of claims 1 to 4, wherein the polypropylene wax ( C ) is a metallocene polypropylene wax.   A colored resin compression molded article obtained by using the colored resin composition for compression molding polypropylene resin (D) according to any one of claims 1 to 5 and the polypropylene resin (D). The colored resin compression molded article according to claim 6, which is a high-speed compression molded article.