JP2015074711A - Aluminum pigment composition, resin composition including the same, and molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum pigment composition capable of providing a resin composition excellent in brilliance and moldability, a resin composition including the aluminum pigment composition, and a molded article formed from the resin composition.SOLUTION: An aluminum pigment composition contains flaky aluminum powder, and an organic compound which has a thermal degradation starting temperature in the air of 200°C or higher and is liquid at room temperature. A content of the volatile organic compound is 2 mass% or less.

Description

  The present invention relates to an aluminum pigment composition, a resin composition containing the same, and a molded article comprising the resin composition.

  Conventionally, molding materials containing aluminum pigments, mica, and the like have been used to produce molded products and laminates having glitter (see, for example, Patent Documents 1 and 2). Further, Patent Document 3 discloses an aluminum pigment composition that is unlikely to become dust.

JP-A-8-120115 JP 2001-261978 A Japanese Patent Publication No. 6-53859

  Usually, aluminum pigments are in a paste form containing volatile organic compounds such as mineral spirits to make them difficult to become dust. Therefore, when injection molding a resin composition containing an aluminum pigment, there is a problem that mineral spirits volatilize and bubbles and streaks are generated in the molded body.

  The aluminum pigment is scaly and has a particle size of 1 to 100 μm, which is larger than other colored pigments. Therefore, when the resin composition containing an aluminum pigment is injection-molded, there is a problem that individual aluminum particles are not easily aligned, and sufficient glitter cannot be obtained.

  The present invention has been made in view of the above problems, and an aluminum pigment composition capable of providing a resin composition excellent in glitter and moldability, a resin composition containing the aluminum pigment composition, and the resin composition It aims at providing the molded article which consists of.

  As a result of intensive studies on the above problems, the present inventors have an organic compound that has a thermal decomposition starting temperature in air of 200 ° C. or higher and is liquid at room temperature, and has a low content of volatile organic compounds. The present inventors have found that the above problem can be solved by using an aluminum pigment composition, and have completed the present invention.

That is, the present invention is as follows.
[1]
Scaly aluminum powder,
An organic compound that has a thermal decomposition starting temperature in air of 200 ° C. or higher and is liquid at room temperature;
The aluminum pigment composition whose content of a volatile organic compound is 2 mass% or less.
[2]
A resin composition comprising the aluminum pigment composition described in [1] above and a thermoplastic resin.
[3]
A molded article comprising the resin composition as described in [2] above.

  ADVANTAGE OF THE INVENTION According to this invention, the aluminum pigment composition which can obtain the resin composition excellent in luster and a moldability, the resin composition containing this aluminum pigment composition, and the molded article which consists of this resin composition can be provided. .

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the gist thereof. Is possible.

[Aluminum pigment composition]
The aluminum pigment composition according to this embodiment is
Scaly aluminum powder,
An organic compound that has a thermal decomposition start temperature in air of 200 ° C. or higher and is liquid at room temperature;
Content of a volatile organic compound is 2 mass% or less.

  By using such an aluminum pigment composition, there is almost no generation of gas during molding, and there is almost no generation of bubbles or streaks in the molded product. In addition, since the thermal decomposition start temperature in air is 200 ° C. or higher and contains an organic compound that is liquid at room temperature, the compatibility between the scaly aluminum powder and the thermoplastic resin is improved, and the aluminum pigment Since the resin is uniformly dispersed in the thermoplastic resin without agglomerating, it becomes possible to obtain a resin composition excellent in glitter and moldability.

[Scaly aluminum powder]
As the aluminum pigment used in this embodiment, the shape, average particle diameter, average thickness, average aspect ratio, and surface properties that can exhibit the properties required for metallic pigments such as surface gloss, whiteness, and glitter are given. What has is preferable. From such a viewpoint, scaly aluminum powder is used in the present embodiment.

  The average particle size (d50) of the scaly aluminum powder is preferably in the range of 2 to 40 μm, and more preferably in the range of 3 to 30 μm. The average particle size (d50) can be measured by a laser diffraction particle size distribution analyzer SALD-2200. Mineral spirit can be used as a measuring solvent. The measurement is carried out according to the equipment instruction manual. However, as a precaution, the scale-like aluminum powder used as a sample was subjected to ultrasonic dispersion for 2 minutes as a pretreatment, and was put into a dispersion tank to reach an appropriate concentration. After confirmation, start measurement. After the measurement is completed, d50 is automatically displayed on the display unit of the laser diffraction particle size distribution analyzer SALD-2200.

Furthermore, the average thickness (t) of the scaly aluminum powder is preferably in the range of 0.01 to 10 μm, and more preferably in the range of 0.05 to 2 μm. The average thickness (t) can be measured as follows. First, add 1 to 2 mL of 5% stearic acid mineral spirit solution to 1 g of scaly aluminum powder, preliminarily disperse, add 50 mL of petroleum benzine, mix, heat at 40 to 45 ° C. for 2 hours, and filter. The product is suction filtered and powdered, and the water surface diffusion area (WCA) is measured. From this measured value, the average thickness (t) is calculated according to the following formula.
t (μm) = 0.4 / WCA (m ² / g)

The water surface diffusion coating area (WCA) is the weight w (g) of the aluminum pigment sample that has been washed with acetone as a pretreatment and dried, and the coating area A (m ² ) when the sample is floated on the water surface uniformly. Was measured and calculated from the following formula.
WCA (m ² / g) = A (m ² ) / w (g)

Furthermore, the average aspect ratio of the scaly aluminum powder is preferably in the range of 1 to 2500, and more preferably in the range of 10 to 300. Here, the “average aspect ratio” refers to a value obtained by dividing the average particle size (d50) of the scaly aluminum powder by the average thickness (t). Further, the surface property of the scaly aluminum powder is preferably smooth. Specifically, the average aspect ratio is obtained by the following formula.
Average aspect ratio = average particle diameter (d50) (μm) / average thickness (t) (μm)

[Organic compounds that are liquid at high pyrolysis temperature and normal temperature]
The aluminum pigment composition of this embodiment contains an organic compound that has a thermal decomposition start temperature in air of 200 ° C. or higher and is liquid at room temperature (25 ° C.).

  Although it does not specifically limit as an organic compound which is thermal decomposition start temperature in air at 200 degreeC or more at normal temperature, For example, adipic acid ester, such as dioctyl adipate, trimellitic acid ester, phosphoric acid ester, naphthene Polyhydric alcohol fatty acid ester or derivative thereof such as polyhydric hydrocarbon oil, paraffinic hydrocarbon oil, isoparaffinic hydrocarbon oil, liquid paraffin, liquid polyethylene wax, polyoxyethylene bisphenol A dilaurate, pentaerythritol monooleate; Silicone oils such as siloxane and polydimethyldiphenylsiloxane are used.

  The thermal decomposition starting temperature is 200 ° C. or higher, preferably 230 ° C. or higher, more preferably 250 ° C. or higher. When the thermal decomposition starting temperature is 200 ° C. or higher, gas generation due to decomposition of the organic compound during molding is almost eliminated, and thus moldability and stability are further improved.

  The thermal decomposition start temperature in air is 200 ° C. or higher, and the content of the organic compound that is liquid at room temperature is 1% by mass to 60% by mass with respect to 100% by mass of the aluminum pigment composition. More preferably, it is 10 mass% or more and 40 mass% or less, More preferably, it is 10 mass% or more and 30 mass% or less. When the content of the organic compound is 1% by mass or more, the orientation of the scaly aluminum powder in the resin composition is improved, and the glitter tends to be improved. Moreover, when the content of the organic compound is 60% by mass or less, solid-liquid separation does not occur, and a uniform aluminum pigment composition tends to be obtained.

[Volatile organic compounds]
The aluminum pigment composition according to this embodiment includes a volatile organic compound. The content of the volatile organic compound is 2% by mass or less, preferably 1% by mass or less, and more preferably 0.5% by mass or less. When the content of the volatile organic compound is within the above range, the moldability is further improved. In addition, content of a volatile organic compound can be measured by the method as described in an Example.

  Here, the “volatile organic compound” means an organic compound having a boiling point of 50 ° C. or higher and 260 ° C. or lower. Although it does not specifically limit as a volatile organic compound, For example, hydrocarbon solvents, such as mineral spirit, solvent naphtha, toluene, and xylene, used for manufacture of scaly aluminum powder; alcohol solvents, ether solvents, ketones Examples thereof include low-viscosity organic solvents such as solvents and ester solvents.

[Method for producing aluminum pigment composition]
The aluminum pigment composition according to this embodiment is preferably obtained by mixing raw material aluminum powder, a solvent that can be a volatile organic compound, and a grinding aid, and grinding the mixture while supplying oxygen. Note that a medium stirring mill, a ball mill, an attritor or the like can be used for the pulverization. Moreover, the raw material aluminum powder may be in a state dispersed in a solvent.

(Raw material aluminum powder)
Although it does not specifically limit as raw material aluminum powder, For example, the thing with few impurities other than aluminum is preferable. The purity of the raw material aluminum powder is preferably 99.5% by mass or more, more preferably 99.7% by mass or more, and further preferably 99.8% by mass or more. 2-20 micrometers is preferable and, as for the average particle diameter of raw material aluminum powder, 3-12 micrometers is more preferable. Moreover, the manufacturing method of raw material aluminum powder is although it does not specifically limit, The atomizing method is preferable.

(Solvent for grinding)
The solvent used for pulverization is not particularly limited. For example, conventionally used hydrocarbon solvents such as mineral spirit and solvent naphtha; low solvents such as alcohol solvents, ether solvents, ketone solvents and ester solvents. An organic solvent having a viscosity may be mentioned. In addition, the solvent used at the time of a grinding | pulverization can become a volatile organic compound in an aluminum pigment composition.

(Crushing aid)
The grinding aid used in the present embodiment is not particularly limited, but dodecyl (lauryl) amine, tetradecyl (myristyl) amine, hexadecyl (palmityl) amine, octadecyl (stearyl) amine, eicosyl (aralkyl) amine, docosyl (behel) ) Aliphatic amines such as amine, oleylamine, stearylamine; dodecyl (lauryl) acid, tetradecyl (myristyl) acid, hexadecyl (palmityl) acid, octadecyl (stearate) acid, eicosyl (aralkyl) acid, docosyl (beher) acid, olein Higher fatty acids such as acids; higher alcohols such as stearyl alcohol and oleyl alcohol; and other higher amides such as stearic acid amide and oleic acid amide.

  These may be used alone or in combination of two or more. These grinding aids are preferably used in an amount of 0.3 to 10 parts by weight, more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the raw aluminum powder.

(Removal of volatile organic compounds)
The aluminum pigment after pulverization contains the above-mentioned volatile organic compound (solvent during pulverization). Therefore, it is necessary to remove volatile organic compounds to 2% or less. As a method for removing the volatile organic compound, a known method can be used. For example, the method of heating the aluminum pigment composition containing many volatile organic compounds under reduced pressure, and evaporating a volatile organic compound is mentioned.

  The method for adding the organic compound is not particularly limited. For example, after removing the volatile organic compound, the organic compound may be added and mixed well with a known mixer such as a mixer. Alternatively, only the volatile organic compound may be evaporated by adding the organic compound and heating it under reduced pressure while containing the volatile organic compound.

(Resin composition)
The resin composition according to the present embodiment includes a thermoplastic resin and the above-described aluminum pigment composition.

(Thermoplastic resin)
The thermoplastic resin used in the present embodiment is not particularly limited as long as it is a thermoplastic resin. Such a thermoplastic resin is not particularly limited. For example, acrylonitrile-butadiene-styrene resin (ABS resin), acrylonitrile-styrene-acrylate resin (ASA resin), acrylonitrile-ethylene-propylene-diene-styrene resin (AES). Resin) and other rubber-reinforced resins; polystyrene (PS resin), styrene-acrylonitrile copolymer (AS resin), styrene-maleic anhydride copolymer, (meth) acrylic acid ester-styrene copolymer (Co) polymer; Olefin resin such as polyethylene and polypropylene; Cyclic polyolefin resin; Polyester resin; Polyamide resin; Polycarbonate resin; Polyarylate resin; Polyacetal resin; Polyvinyl chloride, Ethylene-vinyl chloride Polymers, vinyl chloride resins such as polyvinylidene chloride; (meth) acrylic resins such as (co) polymers using one or more (meth) acrylic esters such as polymethyl methacrylate (PMMA); polyphenylene ether Polyphenylene sulfide; fluorine resins such as polytetrafluoroethylene and polyvinylidene fluoride; liquid crystal polymers; imide resins such as polyimide, polyamideimide, and polyetherimide; ketone resins such as polyetherketone and polyetheretherketone; Examples thereof include sulfone resins such as polyethersulfone; urethane resins; polyvinyl acetate; polyethylene oxide; polyvinyl alcohol; polyvinyl ether; polyvinyl butyral; phenoxy resin; These may be used alone or in combination of two or more. Among these, polycarbonate resins, polyester resins, and mixtures of these with other thermoplastic resins, which have a particularly high molding temperature, are preferable in terms of moldability and stability.

  The content of the aluminum pigment composition contained in the resin composition according to this embodiment is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin. And more preferably 0.5 to 5 parts by mass. When the content of the aluminum pigment composition is 0.05 parts by mass or more, the glitter tends to be more excellent. On the other hand, when the content of the aluminum pigment composition is 20 parts by mass or less, the moldability tends to be further improved.

[Method for producing resin composition]
The resin composition according to the present embodiment can be obtained by mixing a thermoplastic resin and an aluminum pigment. Although it does not specifically limit as a mixing method, For example, generally the method of melt-kneading with a Banbury mixer, a uniaxial and a biaxial extruder, an extruder with a vent, a kneader, a roll, a feeder ruder etc. is mentioned. Thereby, a uniform resin composition can be obtained. The kneading temperature may be appropriately selected depending on the type of thermoplastic resin.

  In order to improve the mixability and dispersibility of the thermoplastic resin and the scaly aluminum powder, the resin composition having a large proportion of the scaly aluminum powder (for example, 30% by mass to 70% by mass) is used as an intermediate (master batch). You may produce as. This intermediate and thermoplastic resin can be further mixed to produce a metallic resin composition containing scaly aluminum powder within the above range.

[Other additives]
The resin composition according to the present embodiment may include an additive depending on the purpose. Examples of such additives include, but are not limited to, mica, coloring pigments, phosphorescent pigments, coloring dyes, colorants such as fluorescent dyes, fillers, antioxidants, anti-aging agents, heat stabilizers, and weathering stability. Agent, ultraviolet absorber, infrared absorber, photochromic agent, antifouling agent, antistatic agent, plasticizer, lubricant, lubricant, surfactant, flame retardant, fluorescent whitening agent, light diffusing agent, crystal nucleating agent, flow Examples thereof include a modifier, an impact modifier, and a pigment dispersant.

〔Molding〕
The molded product according to the present embodiment is made of a resin composition. The molded product according to the present embodiment can be produced from the resin composition by a known method, for example, using an injection molding machine. Such a molded article can be suitably used for a molded article having a glittering property, a laminate, for example, a casing of an electronic device such as a notebook computer or a mobile phone.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, this invention is not restrict | limited to a following example. In addition, the measuring method of the various physical properties used in a manufacture example, an Example, and a comparative example is as follows.

(Measurement method of volatile organic compound content)
The volatile organic compound content was measured by a heating residue measurement method defined in JIS K 5906. Specifically, by taking 5 g of an aluminum pigment composition in an evaporating dish, calculating the heating residue from the ratio of the remaining mass after heating at 105 ° C. × 3 hours and 5 g, and subtracting the heating residue from 100%. The volatile organic compound content (% by mass) in the aluminum pigment composition was calculated.

(Measuring method of average particle diameter of aluminum pigment composition)
The average particle size of the aluminum pigment composition was measured with a laser diffraction particle size distribution analyzer SALD-2200. Mineral spirit was used as a measurement solvent. The measurement was performed according to the instrument instruction manual. The sample was subjected to ultrasonic dispersion for 2 minutes as a pretreatment, and was put into a dispersion tank to confirm that it had an appropriate concentration, and then subjected to measurement.

(1) Brightness:
A test piece having a length of 50 mm, a width of 40 mm, and a thickness of 3 mm was molded using the pellets of the resin composition produced in Examples and Comparative Examples, and visually judged according to the following evaluation criteria.
(Evaluation criteria)
A: The glitter was very excellent.
○: The glitter was excellent.
Δ: The glitter was low.
X: There was almost no glitter.

(2) Formability (appearance):
From two gates provided on one side of a box-shaped molded product mold having a width of 150 mm, a length of 200 mm, and a thickness of 3 mm, the resin composition pellets produced in Examples and Comparative Examples were injection molded. Using the obtained molded product, visual judgment was made according to the following evaluation criteria.
(Evaluation criteria)
○: No bubbles or streaks were seen.
Δ: Some bubbles and streaks were seen.
X: Bubbles and streaks were clearly seen.

(3) Average particle diameter The average particle diameter (d50) of the aluminum pigment was measured with a laser diffraction particle size distribution analyzer SALD-2200.

(Thermoplastic resin)
The thermoplastic resins used in the examples and comparative examples are shown below.
a) Polypropylene: Prime Polypro J106G manufactured by Prime Polymer Co., Ltd.
b) Polymethylmethacrylate (PMMA): Delpet 60N manufactured by Asahi Kasei Chemicals Corporation
c) Polystyrene: PS Japan-made PSJ-polystyrene GPPS HF77
d) Acrylonitrile-butadiene-styrene (ABS): Stylac 321 manufactured by Asahi Kasei Chemicals Corporation
e) Polyamide 66: Leona 1300S manufactured by Asahi Kasei Chemicals Corporation
f) Polyacetal: Tenac C 4520 manufactured by Asahi Kasei Chemicals Corporation
g) Polycarbonate: Panlite L-1225L manufactured by Teijin Chemicals Ltd.
h) Polybutylene terephthalate (PBT): Toraycon 1401-X06 manufactured by Toray Industries, Inc.

(Aluminum pigment)
(Production Example 1)
Raw material aluminum powder (product name # 350M, manufactured by Minalco Co., Ltd.) manufactured by the atomizing method with an average particle size of 30 μm in the shape of a candy, 3 g of stearylamine, mineral spirit (manufactured by JX Nippon Oil & Energy Corporation, product name Cactus) Using 500 mL of solvent (boiling point 150 to 200 ° C.) as a raw material, this was charged in a ball mill with an internal volume of 5000 mL together with 5 kg of 3.2φ bearing balls, and pulverized at a speed of 60 revolutions per minute for 7 hours. During this time, 100 mL of air per minute was sent into the ball mill by a compressor. After the pulverization, the slurry was passed through a 37 μm sieve to remove coarse particles, and then the excess solvent was removed by a filter press to obtain a cake having a heating residue of 82%.

  This cake was transferred to a vertical mixer, and 11 g of dioctyl adipate (manufactured by J Plus Co., Ltd., air decomposition start temperature> 250 ° C.) was added, followed by stirring at a temperature of 80 ° C. and a pressure of 1 kPa for 8 hours. The mineral spirit was volatilized by holding.

  The content of the volatile organic compound in the obtained aluminum pigment composition was 1.3% by mass, and the average particle size was 20 μm.

(Production Example 2)
In place of 3 g of stearylamine in Production Example 1, 3 g of oleic acid was used, and instead of dioctyl adipate, polyoxyethylene bisphenol A dilaurate (Exopar BP-DL manufactured by Kao: 220 ° C. decomposition start temperature in air) An aluminum pigment was produced in the same manner as in Production Example 1 except that it was used. The obtained aluminum pigment composition had a volatile organic compound content of 0.7% and an average particle size of 21 μm.

(Production Example 3)
Instead of 3 g of stearylamine of Production Example 1, 3 g of oleic acid was used, and instead of dioctyl adipate, SUNPURE NX-90 (a naphthenic hydrocarbon oil manufactured by Nippon San Oil Co., Ltd., a decomposition start temperature in air of 230 ° C.) An aluminum pigment was produced in the same manner as in Production Example 1 except that was used. The obtained aluminum pigment composition had a volatile organic compound content of 0.7% and an average particle size of 21 μm.

(Production Example 4)
Instead of 3 g of stearylamine in Production Example 1, 3 g of oleic acid was used, and instead of dioctyl adipate, VERSA-FLOW EV (manufactured by liquid polyethylene wax, Shamrock Technologies, decomposition start temperature in air of 240 ° C.) was used. Except for this, an aluminum pigment was produced in the same manner as in Production Example 1. The obtained aluminum pigment composition had a volatile organic compound content of 0.7% and an average particle size of 21 μm.

(Production Example 5)
Instead of 3 g of stearylamine of Production Example 1, 3 g of oleic acid was used, and instead of dioctyl adipate, NA solvent (isoparaffinic hydrocarbon oil, NOF's decomposition start temperature 210 ° C. in air) was used. Except for this, an aluminum pigment was produced in the same manner as in Production Example 1. The obtained aluminum pigment composition had a volatile organic compound content of 0.7% and an average particle size of 21 μm.

(Production Example 6)
A ball mill having an inner diameter of 30 cm and a length of 35 cm is filled with 600 g of raw material aluminum powder (average particle size 20 μm, manufactured by Minalco, product name # 400) manufactured by the atomizing method, 1.2 kg of mineral spirits, and 6 g of stearic acid. Then, 18 kg of a steel ball (specific gravity 7.8) having a diameter of 4.8 mm was pulverized at 60 rpm for 5 hours. After pulverization, the slurry in the ball mill was washed out with mineral spirit, passed through a 400 mesh vibrating screen, and the passed slurry was filtered and concentrated with a filter press to obtain a cake with a heating residue of 87%. The obtained cake is transferred into a vertical mixer, and a predetermined amount of solvent naphtha (manufactured by TonenGeneral Sekiyu KK, product name Solvesso 100, decomposition start temperature in air of 180 ° C.) is added, mixed for 15 minutes, and heated residue A 75% aluminum pigment composition was obtained. The average particle size was 15 μm and the volatile organic compound content was 25%.

(Production Example 7)
Aluminum was prepared in the same manner as in Production Example 1 except that polyethylene glycol PEG # 200 (manufactured by NOF Corporation, decomposition start temperature in air 170 ° C.) was used instead of dioctyl adipate in Production Example 1. A pigment was produced. The content of the volatile organic compound in the obtained aluminum pigment composition was 0.8%, and the average particle size was 20 μm.

[Examples 1-12, Comparative Examples 1-2]
The thermoplastic resin and the aluminum pigment produced in Production Examples 1 to 7 were mixed in the proportions shown in Table 1, and a 20 mmφ twin screw extruder was used, and the resin temperature was adjusted appropriately from 200 ° C. to 300 ° C. according to the resin. Under the conditions, the resin composition pellets obtained by mixing the two were obtained by melt mixing and extrusion. The pellets were molded using an injection molding machine, and the glitter and moldability were visually evaluated. The results are shown in Table 1. In Comparative Example 1, a large number of aggregates of scaly aluminum powder as well as bubbles and streaks were found in the molded product.

  The aluminum pigment composition according to the present invention, and the resin composition containing the aluminum pigment composition can be applied to a molded article having a glitter property, a laminate, for example, a casing of an electronic device such as a notebook computer or a mobile phone, Has industrial applicability.

Claims (3)

Scaly aluminum powder,
An organic compound that has a thermal decomposition starting temperature in air of 200 ° C. or higher and is liquid at room temperature;
The aluminum pigment composition whose content of a volatile organic compound is 2 mass% or less.   A resin composition comprising the aluminum pigment composition according to claim 1 and a thermoplastic resin.   A molded article comprising the resin composition according to claim 2.