JP7810002B2 - Pigment composition, resin composition, and molded article - Google Patents

Description

The present invention relates to a pigment composition for coloring nylon 6 and/or nylon 6,6 resin, a resin composition containing the same, and a molded article made from the resin composition.

The market for pigments for coloring plastics (especially engineering plastics) demands pigments with high heat resistance and high stability. Currently, such pigments include phthalocyanine pigments and quinacridone pigments. In particular, the following patent documents 1 to 4 list phthalocyanine pigments for coloring plastics.

Patent Documents 1-4 describe setting the number of halogen substituents, such as chlorine, in halogenated metal phthalocyanine pigments within a specific range. They also describe resins to be colored, such as polyethylenes, such as high-density polyethylene (HDPE) and low-density polyethylene (LDPE), polyolefins, such as polypropylene, polyester resins, such as polyethylene terephthalate, polyamide resins, such as nylon 6 and nylon 66, polystyrene resins, and thermoplastic ionomer resins.

Japanese Patent Application Laid-Open No. 2004-131612 JP 2015-183071 A Japanese Patent Application Laid-Open No. 2016-023222 Japanese Unexamined Patent Publication No. 2-91159

As a result of our investigations, the inventors have found that, among the halogenated metal phthalocyanine pigments and colored resins described in Patent Documents 1-4, certain combinations of chlorinated metal phthalocyanine pigments with a certain number of chlorines or more and nylon 6 and nylon 66 resins cause significant fading of the phthalocyanine pigment at high temperatures during injection molding and a significant change in hue before and after molding (see Comparative Examples 1 and 2 of the present application). Surprisingly, this fading and change in hue before and after molding did not occur when the resin was changed to a resin other than nylon 6 and nylon 66 resin (for example, polypropylene) (see Comparative Examples 4 and 5 of the present application).

Nylon 6 and nylon 66 are engineering plastics widely used in textiles, automotive parts, electrical and electronic devices, and various molded products, making them important resins in industry. The present invention provides a pigment composition containing chlorinated metal phthalocyanine for coloring nylon 6 and nylon 66 resins, which is resistant to fading and hue changes before and after molding, even at high temperatures (e.g., 260-300°C) during injection molding.

The inventors suspected that the primary cause of discoloration and hue change during molding was a change in pigment structure due to a chemical reaction between the nylon resin and the chlorinated metal phthalocyanine pigment, and further investigated the number of chlorine substituents that are thought to contribute to the reaction. As a result, they found that with specific combinations of chlorinated metal phthalocyanine pigments with a chlorine number of less than four and nylon 6 and nylon 66 resins, there was almost no discoloration at high temperatures during injection molding, and almost no change in hue before and after molding.

The mechanism assumed in the present invention is as follows.
Typically, phthalocyanine pigments have a planar structure with π-electron conjugation extending throughout the molecule, providing heat resistance. Furthermore, when the coloring resin is nylon resin, the amide bonds in the nylon resin interact with the phthalocyanine pigment, stabilizing the structure. Therefore, the phthalocyanine pigment is less likely to fade or change in hue before and after molding, as described above. However, in the case of chlorinated metal phthalocyanine pigments, the presence of chlorine atoms, which are electron-withdrawing groups, weakens the π-electron conjugation throughout the molecule because electrons are attracted to the chlorine atoms at the ends of the structure. As a result, the interaction between the amide bonds in the phthalocyanine pigment and the nylon resin also weakens, leaving the chlorinated metal phthalocyanine pigment in an unstable, free state, which tends to reduce its heat resistance. Furthermore, a chemical reaction between the chlorine atoms in the chlorinated metal phthalocyanine pigment and the amide groups in the nylon resin can cause fading and hue changes. In this mechanism, if the number of substituted chlorine atoms in the chlorinated metal phthalocyanine pigment exceeds four, the resulting decrease in heat resistance, such as fading and hue changes, is thought to become significant.
Furthermore, among commonly used nylon resins, nylon 6 and nylon 6,6 have a relatively high proportion of amide bonds in the polymer structure, and it is believed that the interaction between the amide bonds and the phthalocyanine pigment in the above-mentioned mechanism has a large effect. Note that it is believed that resins other than nylon (e.g., polypropylene) do not suffer from the deterioration in heat resistance, such as fading and hue change, due to the above-mentioned mechanism.

That is, the present invention is
"Item 1. A pigment composition for coloring nylon 6 and/or nylon 6,6 resin, containing a metal phthalocyanine pigment having an average number of chlorine substituents of less than 4.
Item 2. The pigment composition according to Item 1, wherein the central metal in the metal phthalocyanine pigment is copper.
Item 3. A resin composition comprising a metal phthalocyanine pigment having an average number of chlorine substituents of less than 4 and a nylon 6 and/or nylon 6,6 resin having an average molecular weight of 10,000 to 25,000.
Item 4. A molded article molded using the resin composition according to Item 3.
Regarding.

When used to color nylon 6 and/or nylon 6,6 resin, the pigment composition of the present invention exhibits excellent heat resistance, with minimal fading or hue change at high temperatures (e.g., 260-300°C) during injection molding. Furthermore, the resin composition of the present invention also exhibits excellent heat resistance.

The present invention is described in detail below.

<Pigment Composition>
The pigment composition of the present invention is for coloring nylon 6 and/or nylon 6,6 resin, and contains a metal phthalocyanine pigment having an average number of chlorine substituents of less than 4. The average number of chlorine substituents in the metal phthalocyanine pigment is preferably 0 to 3, more preferably 0 to 2, and even more preferably 0 to 1. When the average number of chlorine substituents is within the above range, fading and hue change at high temperatures during injection molding are small, and the heat resistance is excellent. The metal phthalocyanine pigment may have substituents other than chlorine (for example, fluorine or bromine).

The central metal in the above metal phthalocyanine pigments can be, for example, copper (Cu), zinc (Zn), nickel (Ni), cobalt (Co), iron (Fe), aluminum (Al), chromium (Cr), or manganese (Mn), with copper being preferred. Copper phthalocyanine pigments with copper as the central metal are widely used in the field of plastic coloring, and have been found to exhibit excellent heat resistance in particular in the present invention. Copper phthalocyanine can take various crystal forms, including α-, β-, and ε-types. From the standpoint of heat resistance, α- or β-types are preferred, with β-types being more preferred.

Examples of the metal phthalocyanine pigment include blue pigments such as C.I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, and 15:6. Of these, copper phthalocyanine pigments such as C.I. Pigment Blue 15:1, 15:3, and 15:4 are preferred for the present invention. In the present invention, the metal phthalocyanine pigments may be used alone or in combination of two or more.

Copper phthalocyanine pigments can be synthesized using methods such as the urea method, which uses phthalic anhydride, urea, and a copper compound as starting materials, or the phthalodinitrile method, which uses phthalodinitrile and a copper compound to synthesize them. Synthesized copper phthalocyanine pigments may also be used in the present invention. Commercially available copper phthalocyanine pigments may also be used, such as the FASTOGEN® BLUE series (manufactured by DIC Corporation) and the SUNFAST® BLUE series (manufactured by Sun Chemical Co., Ltd.).

The pigment composition of the present invention may contain metal phthalocyanine pigments other than the above-mentioned metal phthalocyanine pigments (such as C.I. Pigment Green 7 and 36) or other pigments (organic pigments such as threne-based pigments, indigo-based pigments, perinone-based pigments, perylene-based pigments, phthalone-based pigments, dioxazine-based pigments, quinacridone-based pigments, isoindolinone-based pigments, metal complex-based pigments, diketopyrrolopyrrole-based pigments, and azo pigments, as well as inorganic pigments such as titanium oxide and carbon black), provided that the effects of the present invention are not impaired.

The pigment composition of the present invention is used for coloring nylon 6 and/or nylon 6,6 resin, and the average molecular weight of these nylons is preferably 10,000 to 25,000, more preferably 12,000 to 18,000. If the average molecular weight is less than 10,000, the pigment and resin will be highly compatible, making it difficult to ensure high heat resistance. If the average molecular weight exceeds 25,000, the pigment and resin will be less compatible, which may result in uneven color. This average molecular weight is the number average molecular weight and can be measured by GPC analysis using polystyrene as a standard substance.

Nylon 6 (PA6) can be synthesized by ring-opening polymerization of caprolactam (carbon number 6), but commercially available products that can be used include UBE Nylon (manufactured by Ube Industries, Ltd.), Tanajin (registered trademark) TN200, TN500, etc. (manufactured by Takayasu Co., Ltd.), Glamid (registered trademark) T-802, etc. (manufactured by Toyobo Co., Ltd.), Amilan (registered trademark) CM1017, CM1007, CM1026, etc. (manufactured by Toray Industries, Inc.), and Unitika Nylon 6 (manufactured by Unitika Ltd.). Nylon 66 (PA66) may also be synthesized by condensation polymerization of hexamethylenediamine (carbon number 6) and adipic acid (carbon number 6), but commercially available products that can be used include Leona (registered trademark) 1300S (manufactured by Asahi Kasei Corporation), Tanajin (registered trademark) TN720, TN710 (manufactured by Takayasu Co., Ltd.), Glamid (registered trademark) T-662 (manufactured by Toyobo Co., Ltd.), and Amilan (registered trademark) CM3007, CM3001-N (manufactured by Toray Industries, Inc.).

The reasons why nylon 6 and nylon 6,6 are chosen as nylons (polyamide resins) in the present invention will be described in detail below.
Generally, there are the following types of nylon (indicating the monomers and the number of carbon atoms that make up each).
Nylon 6: ε-caprolactam (carbon number 6)
Nylon 11: undecane lactam (carbon number 11)
Nylon 12: Lauryl lactam (carbon number 12)
Nylon 6,6: hexamethylenediamine (carbon number 6) + adipic acid (carbon number 6)
Nylon 6,10: hexamethylenediamine (carbon number 6) + sebacic acid (carbon number 10)
Nylon 6T: Hexamethylenediamine (carbon number 6) + terephthalic acid
Nylon 6I: Hexamethylenediamine (carbon number 6) + Isophthalic acid
Nylon 9T: Nonanediamine (carbon number 9) + terephthalic acid
Nylon M5T: Methylpentadiamine (methyl group + carbon number 5) + terephthalic acid
In the present invention, as explained by the above-mentioned mechanism, a relatively high proportion of amide bonds in the polymer structure is preferable, and therefore, a polymer having a small number of constituent carbon atoms and free of aromatic structures other than amide bonds, such as phthalic acid, is preferred. Therefore, in the present invention, aliphatic polyamides, particularly nylons having 5 or 6 constituent carbon atoms, are preferred. For these reasons, the pigment composition of the present invention is intended for coloring nylon 6 and/or nylon 6,6 resins.

The pigment composition of the present invention preferably contains a pigment dispersant in addition to the pigment. Examples of such pigment dispersants include metal soaps such as calcium stearate, zinc stearate, magnesium stearate, and lithium stearate; fatty acid amides such as stearamide and ethylene bisamide; ester waxes; polyethylene waxes; and silane coupling agents. Magnesium stearate is particularly preferred. The amount of pigment dispersant per 100 parts by mass of pigment is, for example, 50 to 500 parts by mass, and preferably 100 to 400 parts by mass.

The resin coloring method for the pigment composition of the present invention may be any method, such as masterbatch, dry color, or paste color (liquid masterbatch).

<Resin composition>
The resin composition of the present invention contains a metal phthalocyanine pigment having an average number of chlorine substituents of less than four, and a nylon 6 and/or nylon 6,6 resin having an average molecular weight of 10,000 to 25,000. The metal phthalocyanine pigment is as described above for the pigment composition of the present invention, and the nylon 6 and/or nylon 6,6 resin is as described above for the pigment composition of the present invention. The resin composition of the present invention may also contain the pigment dispersant described above for the pigment composition of the present invention.

The ratio of the pigment containing the metal phthalocyanine pigment to 100 parts by mass of nylon 6 and/or nylon 6,6 resin is, for example, 0.001 to 1 part by mass, preferably 0.01 to 0.5 parts by mass. Furthermore, the ratio of the pigment composition of the present invention, in which a pigment dispersant is added to the pigment, to 100 parts by mass of nylon 6 and/or nylon 6,6 resin is, for example, 0.002 to 1 part by mass, preferably 0.01 to 0.5 parts by mass.

The resin composition of the present invention may contain resins other than the above-mentioned nylon 6 and/or nylon 6,6 resins, as long as the effects of the present invention are not impaired. Examples of such resins include polyamide resins other than nylon 6 and nylon 6,6; homopolymers and copolymers using ethylene, propylene, butylene, styrene, etc. as monomer components; polyethylenes such as high-density polyethylene (HDPE), linear low-density polyethylene (L-LDPE), and low-density polyethylene (LDPE); polyolefin resins such as polypropylene and polybutylene; polyester resins such as polyethylene terephthalate; polystyrene resins; and thermoplastic ionomer resins.

The resin composition of the present invention may contain, in addition to the above-mentioned metal phthalocyanine pigment, other pigments and pigment dispersants, nylon 6 and/or nylon 6,6, and other resins, lubricants, plasticizers, fillers, weather stabilizers, various additives, etc.

The lubricant may be either an internal or external lubricant, and examples include hydrocarbon compounds such as paraffin wax, synthetic polyethylene, and liquid paraffin; fatty acid and higher alcohol compounds such as stearic acid, behenic acid, 12-hydroxystearic acid, and stearyl alcohol; fatty acid amide compounds such as stearic acid amide, oleic acid amide, erucic acid amide, methylene bisstearic acid amide, and ethylene bisstearic acid amide; and ester compounds such as glycerin monostearate, glycerin monooleate, and butyl stearate.

The above-mentioned plasticizers include epoxidized vegetable oils such as epoxidized soybean oil (ESBO) and epoxidized linseed oil (ELSO), phthalate esters such as dioctyl phthalate (DOP) and dibutyl phthalate (DBP), and polyester compounds such as polyesters of dibasic acids (adipic acid, sebacic acid, phthalic acid, etc.) and glycols (1,2-propanediol, butanediol, etc.).

The filler can be selected from a variety of materials depending on the desired physical properties, including wollastonite, potassium titanate, xonotlite, gypsum fiber, aluminum borate, MOS, aramid fiber, various fibers, carbon fiber, glass fiber, talc, mica, glass flakes, polyoxybenzoyl whiskers, calcium carbonate, talc, silica, and clay.

Examples of the weathering stabilizers include ultraviolet absorbers such as triazine-based, benzotriazole-based, benzophenone-based, salicylate-based, and cyanoacrylate-based compounds; light stabilizers such as hindered amine light stabilizers (HALS); antioxidants such as phenol-based (e.g., hindered phenol-based), phosphorus-based (e.g., phosphite-based), and sulfur-based (e.g., thioether-based) antioxidants; heavy metal deactivators; and chelating agents.

The various additives mentioned above include intumescent, phosphate, halogen, and inorganic flame retardants, nucleating agents such as metal phosphate esters and sorbitol, fillers such as talc and calcium carbonate, compatibilizers (reactive and non-reactive), clarifying agents such as metal phosphate esters and sorbitol, and nonionic, anionic, and cationic antistatic agents.

The resin composition of the present invention contains a metal phthalocyanine pigment having an average number of chlorine substituents of less than four and nylon 6 and/or nylon 6,6 resin, and therefore, like the pigment composition of the present invention, exhibits little fading or hue change at high temperatures during injection molding and excellent heat resistance. The resin composition of the present invention may be colored using any method, including masterbatch, dry color, or paste color (liquid masterbatch).

<Molded product>
The molded article of the present invention is a colored nylon 6 or nylon 6,6 article molded using the resin composition of the present invention. The molding method may be any of injection molding, blow molding, inflation molding, extrusion molding, Engel molding, vacuum molding, etc., but injection molding is preferred. Injection molding can be performed under typical conditions for molding nylon 6 and nylon 6,6, with the resin temperature (cylinder temperature) being, for example, 260 to 300°C.

The molded articles of the present invention can be used for a variety of purposes, including automobile and vehicle parts (engine compartment parts, intake system parts, fuel system parts, etc.), electrical and electronic equipment (industrial equipment connectors, switches, housings, etc.), injection and extrusion molded products for processing such as films, sheets, pipes, plates, round bars, and tubes, as well as everyday items, containers, toys, building materials, and sporting goods.

The present invention will be explained in more detail below using examples and comparative examples.

[Example 1]
First, 1 g of FASTOGEN BLUE 5050GE (CI Pigment Blue 15:1) manufactured by DIC Corporation and 1 g of magnesium stearate manufactured by Sakai Chemical Industry Co., Ltd. were thoroughly mixed to prepare 2 g of dry color. Next, the prepared dry color was added to 1,000 g of nylon resin (nylon 6, product name: UBE NYLON 1013NW8, manufacturer: Ube Industries, Ltd.) and thoroughly mixed to obtain colored pellets. These colored pellets were then placed in an injection molding machine (manufactured by Nissei Plastic Industrial Co., Ltd.; model number: PNX60III-5A) and molded at 280°C with residence times of 0 and 10 minutes.

[Example 2]
Molding was carried out in the same manner as in Example 1, except that the pigment was changed to FASTOGEN BLUE GR-6LK (CI Pigment Blue 15:3) manufactured by DIC Corporation.

[Example 3]
Molding was carried out in the same manner as in Example 1, except that the pigment was changed to SUNFAST BLUE 15:4 249-3450 (CI Pigment Blue 15:4) manufactured by SUN.

[Example 4]
Molding was carried out in the same manner as in Example 1, except that the pigment was changed to SUNFAST BLUE 15:1 248-4816 (CI Pigment Blue 15:1) manufactured by SUN.

[Comparative Example 1]
Molding was carried out in the same manner as in Example 1, except that the pigment was changed to SUNFAST GREEN 36 264-7036 (CI Pigment Green 36) manufactured by SUN.

[Comparative Example 2]
Molding was carried out in the same manner as in Example 1, except that the pigment was changed to SUNFAST GREEN 7 264-7405 (CI Pigment Green 7) manufactured by SUN.

[Comparative Example 3]
2 g of dry color, which was a pre-mix of 1 g of DIC's FASTOGEN BLUE 5050GE (CI Pigment Blue 15:1) and 1 g of Sakai Chemical Industry's magnesium stearate, was added to 1,000 g of polypropylene resin (product name: Novatec PP MA3, manufacturer: Japan Polypropylene Corporation) and mixed thoroughly. This mixture was then placed in an injection molding machine (Nissei Plastic Industrial Co., Ltd.) and molded at 280°C with residence times of 0 and 10 minutes.

[Comparative Example 4]
Molding was carried out in the same manner as in Comparative Example 3, except that the pigment was changed to SUNFAST GREEN 36 264-7036 (CI Pigment Green 36) manufactured by SUN Corporation.

[Comparative Example 5]
Molding was carried out in the same manner as in Comparative Example 3, except that the pigment was changed to SUNFAST GREEN 7 264-7405 (CI Pigment Green 7) manufactured by SUN Corporation.

[Heat resistance evaluation]
Two molded plates molded at 280°C for residence times of 0 and 10 minutes were measured for color. The color measurement value of the molded plate with a residence time of 0 minutes was used as the reference color, and the dE* value of the molded plate with a residence time of 10 minutes was calculated. Note that pigments with smaller dE* values have higher heat resistance and stability.

As shown in Table 1 above, when the metal phthalocyanine pigments of Examples 1-4, each having a chlorine number of less than 4, were used with nylon 6, the dE/nylon value was smaller than that of Comparative Examples 1-2, each having a chlorine number of 4 or more, resulting in higher heat resistance and stability. On the other hand, when the metal phthalocyanine pigment of Comparative Example 3, each having a chlorine number of less than 4, was used with polypropylene resin (PP), the dE/PP value was larger than that of Comparative Example 4, each having a chlorine number of 4, resulting in lower heat resistance and stability. In other words, the pigment composition of the present invention was found to be useful for coloring nylon 6 and/or nylon 6,6 resin.

Claims (6)

a pigment composition;
A resin composition containing nylon 6 and/or nylon 6,6 resin,
the pigment composition contains only a copper phthalocyanine pigment having an average number of chlorine substituents of 0 to 2 as a pigment,
the ratio of the pigment to 100 parts by mass of the nylon 6 and/or nylon 6,6 resin is 0.001 to 0.5 parts by mass;
The resin composition, wherein the copper phthalocyanine pigment having an average number of chlorine substituents of 0 to 2 is selected from the group consisting of C.I. Pigment Blue 15:1 and C.I. Pigment Blue 15:4 . The resin composition according to claim 1 , wherein the pigment composition further comprises a pigment dispersant. 3. The resin composition according to claim 2, wherein the pigment dispersant is magnesium stearate. 4. The resin composition according to claim 2 , wherein the amount of the pigment dispersant is 50 to 500 parts by mass relative to 100 parts by mass of the pigment. The resin composition according to any one of claims 1 to 4, wherein the number average molecular weight of the nylon 6 and/or nylon 6,6 resin is 10,000 to 25,000. A molded article molded using the resin composition described in any one of claims 1 to 5.