JP2777522B2 - Resin composition containing weather-resistant pearlescent pigment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition containing a novel weather-resistant pearlescent pigment, and more particularly to a resin composition containing visible light, ultraviolet light, a high humidity atmosphere and an atmosphere under a fluorescent lamp as compared with conventional ones. An object of the present invention is to provide a resin composition having excellent weather resistance, which gives a resin molded product that does not yellow even when left for a long time and can maintain excellent commercial value.

[0002]

2. Description of the Related Art Conventionally, resin moldings having pearl luster have been
It has a so-called luxurious feeling and is widely used for bottles of cosmetics, shampoos and the like. These molded products are usually formed by kneading a pearlescent pigment together with an antioxidant or the like into a polyolefin resin, and then performing blow molding or injection molding. However, particularly when a pearlescent pigment is mixed with a resin such as polyolefin and molded, the molded product may become yellow over time due to the interaction of the metal oxide on the surface of the pearlescent pigment and moisture, visible light or ultraviolet light. There is a problem of changing.

[0003] These phenomena are often further accelerated by the contents contained in the bottles, and yellowing at stores has been a serious problem since the commercial value has been reduced. Several proposals have already been made to solve these problems. For example, there is a method of coating a pearlescent pigment with methacrylate chromium chloride, or a method of surface-treating with an antimony compound, but these methods have a problem in safety, and the obtained molded products are used for food and cosmetics. Not suitable for use. JP-A-60-92359 also proposes a method of coating a pearlescent pigment with a polysiloxane and a rare earth metal compound. However, according to this method, the steps of washing and filtering after pigment treatment become complicated, which leads to an increase in the production cost of the pigment and, consequently, an increase in the production cost of the molded product.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an excellent commercial value without yellowing even when left for a long time in an atmosphere such as visible light, ultraviolet light, a high humidity atmosphere or a fluorescent lamp. An object of the present invention is to provide a resin composition having excellent weather resistance, which gives a resin molded product that can be maintained.

[0005]

The above object is achieved by the present invention described below. That is, the present invention comprises 100 parts by weight of a resin and 0.5 to 20 parts by weight of a pearlescent pigment, wherein the pearlescent pigment is an alkyl having a reactive hydrogen, amino hydrogen group and / or halogen atom in a molecule. It is a resin composition characterized by being surface-coated with polysiloxane.

[0006]

According to the present invention, the surface of a pearlescent pigment is treated with an organosilicon compound such as an alkylpolysiloxane having a reactive group in the molecule, in particular, methylhydrogenpolysiloxane, whereby the surface of the pearlescent pigment is treated. The active site of the existing metal oxide and the above-mentioned reactive group are bonded, and the surface activity of the pearlescent pigment is greatly controlled. As a result, when a pearlescent pigment surface-treated with a reactive alkylpolysiloxane is mixed with a resin such as a polyolefin, the phenomenon that the molded product turns yellow over time due to the interaction of moisture, visible light or ultraviolet light, etc. Can be prevented.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention is described in more detail with reference to preferred embodiments. The reactive alkylpolysiloxane used in the present invention has a reactive hydrogen, amino hydrogen group (for example, —NH, —NH ₂ or the like) and / or a halogen atom (Cl, Br, I) in a molecule, and has a degree of polymerization of n = 7 ~
1,000 dimethylpolysiloxanes, especially n
= 20-100 dimethylpolysiloxane is preferred.

Preferred examples of the reactive alkyl polysiloxane include methyl hydrogen polysiloxane, dimethyl methyl hydrogen copolymerized polysiloxane, dimethyl polysiloxysilazane, dimethyl polysiloxycyclolide, dimethyl polysiloxy bromide, and dimethyl polysiloxy iodine. Methyl hydrogen polysiloxane has many reactive groups and easily reacts with titanium oxide with strong surface activity existing on the surface of the pearlescent pigment, and the surface activity of the pearlescent pigment is greatly suppressed. Is particularly preferred for The reactive group of the reactive alkylpolysiloxane may be directly bonded to a silicon atom, or may be indirectly bonded to a silicon atom via another substituent.

The pearlescent pigments referred to in the present invention are titanium oxide or colored pigments (for example, yellow iron oxide, black iron oxide, red iron oxide, ultramarine, navy blue, chromium oxide) on muscovite, sericite, and other mica. Chromium hydroxide or a tar dye) alone or in the form of a mixture and coated as a single layer or a continuous layer, and the diameter of the pigment particles is 1 to 200 μm. The amount of the reactive alkylpolysiloxane used in the present invention varies depending on the particle size and specific surface area of the pearlescent pigment to be treated, but is used in the range of 0.5 to 30 parts by weight per 100 parts by weight of the pigment. A range of 2 to 5 parts by weight is preferred.

In the present invention, as an example of a method for surface-treating a pearlescent pigment with a reactive alkylpolysiloxane, an organic solvent dissolving the alkylpolysiloxane, for example, ethers, ketones, halogenated hydrocarbons, etc. Aliphatic hydrocarbons and alcohols are added and mixed in a range of 1 to 50% by weight with respect to the pigment to be surface-treated (or the extender used in combination). After that, a method of adding the above-mentioned reactive alkylpolysiloxane to the pigment or extender to be surface-treated while spraying it while mixing and mixing and drying is used. The organic solvent used in the above method is preferably used in consideration of the surface activity and thermal stability of the pigment or extender to be surface-treated and the flash point or ignition point of the organic solvent.

The surface-treated pearlescent pigment thus obtained is mixed with a thermoplastic olefin resin such as polyethylene or polypropylene, and if necessary, additives such as an antioxidant and other coloring agents are added and mixed. The resin composition of the present invention can be obtained by merely performing kneading and granulating the mixture by a conventionally known method such as a Banbury mixer or an extruder to obtain the resin composition of the present invention. Can be
For example, by molding the obtained pellet-shaped composition by an arbitrary molding method such as blow molding or injection molding, a molded product excellent in weather resistance without yellowing can be obtained. At this time, the pearlescent pigment surface-treated with the reactive alkylpolysiloxane as described above has a very excellent dispersibility when blended with a resin such as polyolefin because the surface is uniformly coated with an organic substance. There is also an effect that a high quality colored molded product can be obtained.

The amount of the surface-treated pearlescent pigment is usually preferably 0.5 to 20 parts by weight per 100 parts by weight of the resin. If the amount is less than 0.5 part by weight, a molded article having a sufficient pearl luster cannot be obtained, and if it exceeds 20 parts by weight, a molded article having a preferable color tone cannot be obtained. In the above-mentioned resin molded product, the active site of the metallized product on the surface of the pearlescent pigment incorporated therein is blocked by the alkylpolysiloxane having a reactive group in the molecule, so that the interaction of moisture, visible light, etc. Thereby, it is possible to prevent phenomena such as the molded product turning yellow over time.

[0013]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. Example 1 20 g of benzene was added to 100 g of a mica pearl pigment (average particle size: 20 μm) and mixed for 5 minutes with a mixer, and then methyl hydrogen polysiloxane (n =
40) 2 g was mixed for 5 minutes with spray addition to the above mixture. This was dried at 85 ° C. to completely remove benzene, and then heat-treated at 115 ° C. for 3 hours to obtain a surface-treated pearlescent pigment used in the present invention.

The thus obtained surface-treated mica pearl pigment 10.0 parts and polyethylene resin (Showa Denko Shorex 5003, specific gravity: 0.944, MF
(R: 0.3 g / 10 min) 90.0 parts with a pressure kneader
After kneading at 30 ° C, the mixture was granulated with a 50 mmφ single screw extruder,
A resin composition of the present invention in the form of a master batch having a diameter of mmΦ was obtained.
5.0 parts of this master batch, 94. polyethylene resin.
5 parts and antioxidant (Yoshinox BH manufactured by Yoshitomi Pharmaceutical Co., Ltd.)
T) After blending 0.5 part, a predetermined plate was molded at 250 ° C. using an injection molding machine, and its weather resistance, particularly the degree of yellowing, was evaluated.

Example 2 10.0 parts of the master batch prepared in the above example 10.0 parts Polyethylene resin 89.5 parts Antioxidant (Yoshinox BHT manufactured by Yoshitomi Pharmaceutical) 0.5 part After blending, 250 ° C. using an injection molding machine. Then, a predetermined plate was formed, and its weather resistance, particularly the degree of yellowing was evaluated.

Example 3 20 g of benzene was added to 100 g of mica pearl pigment (average particle diameter: 20 μm), and the mixture was mixed for 5 minutes with a mixer, and 2 g of methyl hydrogen polysiloxane (n = 40) was sprayed on the mixture. Mix for 5 minutes while adding. This was dried at 85 ° C. to completely remove benzene, and then heated at 115 ° C. for 3 hours to obtain a surface-treated pearlescent pigment used in the present invention. 10.0 parts of the surface-treated mica pearl pigment thus obtained and a polypropylene resin (Mitsui Noblen JH-G, manufactured by Mitsui Toatsu Chemicals, specific gravity:
(0.91, MFR: 4.0 g / 10 min) 90.0 parts were kneaded at 230 ° C. in a pressure kneader, and then granulated by a 50 mmφ single screw extruder to obtain a 2 mmφ masterbatch resin composition of the present invention. Obtained. After blending 5.0 parts of this master batch, 94.5 parts of a polypropylene resin and 0.5 part of an antioxidant (Yoshinox BHT manufactured by Yoshitomi Pharmaceutical Co., Ltd.), a predetermined plate was molded at 250 ° C. by an injection molding machine, and the weather resistance was measured. Sex, especially the degree of yellowing was evaluated.

Example 4 10.0 parts of the masterbatch produced in Example 1 above, 89.5 parts of polyethylene resin, 0.5 part of an antioxidant (Yoshinox BHT, manufactured by Yoshitomi Pharmaceutical Co., Ltd.) and 0.5 part of the mixture were blended by an injection molding machine. A given plate was formed at a temperature of ° C., and its weather resistance, particularly the degree of yellowing, was evaluated.

Comparative Example 1 10.0 parts of mica pearl pigment (average particle size: 20 μm) and polyethylene resin (SHOLEX 5 manufactured by Showa Denko)
003, specific gravity 0.944, MFR: 0.3 g / 10 min)
90.0 parts were kneaded at 230 ° C. with a pressure kneader, and then 50 mm
The mixture was granulated by a single-screw extruder to obtain a master batch having a diameter of 2 mm. After blending 5.0 parts of this master batch, 94.5 parts of polyethylene resin and 0.5 part of an antioxidant (Yoshinox BHT, manufactured by Yoshitomi Pharmaceutical Co., Ltd.), the mixture was mixed with an injection molding machine to form a 250.
A predetermined plate was molded at a temperature of ° C, and its weather resistance, particularly the degree of yellowing, was evaluated.

Comparative Example 2 10.0 parts of the master batch prepared in Comparative Example 1 above, 89.5 parts of a polyethylene resin, 0.5 part of an antioxidant (Yoshinox BHT, manufactured by Yoshitomi Pharmaceutical Co., Ltd.) and 0.5 part of a blend were mixed with an injection molding machine. A predetermined plate was formed at a temperature of ° C, and its weather resistance, particularly the degree of yellowing, was evaluated.

Comparative Example 3 10.0 parts of mica pearl pigment (average particle size: 20 μm) and polypropylene resin (Mitsui Noblen JH-G manufactured by Mitsui Toatsu Chemicals, specific gravity: 0.91, MFR: 4.0 g / 1)
0 minutes) After kneading 90.0 parts with a pressure kneader at 230 ° C,
Granulation was performed using a 50 mmφ single screw extruder to obtain a 2 mmφ masterbatch. After blending 5.0 parts of this master batch, 94.5 parts of a polypropylene resin and 0.5 part of an antioxidant (Yoshinox BHT manufactured by Yoshitomi Pharmaceutical Co., Ltd.), a predetermined plate was molded at 250 ° C. by an injection molding machine, and the weather resistance was measured. sex,
In particular, the degree of yellowing was evaluated.

Comparative Example 4 10.0 parts of the master batch prepared in Comparative Example 3 above, 89.5 parts of polypropylene resin, 0.5 part of an antioxidant (Yoshinox BHT, manufactured by Yoshitomi Pharmaceutical Co., Ltd.) and 0.5 part of the mixture were mixed at 250 ° C. by an injection molding machine. Then, a predetermined plate was formed, and its weather resistance, particularly the degree of yellowing was evaluated.

[Evaluation Method for Yellowing Degree-1] The colored molded products prepared in the above Examples and Comparative Examples were placed in a 2-liter desiccator, and 200 ml of 2.8% ammonia water was poured into the desiccator. Seal while exposed inside. At this time, a fluorescent lamp is irradiated from above (the illuminance of the sample surface is about 2,000 Lux), and the sample is maintained at room temperature for 7 days. The yellowing degree (ΔY1) of the colored molded product is measured using a colorimetric color difference meter in accordance with JIS 7103 (Plastic yellowing degree and yellowing degree test method).

[Evaluation Method for Yellowing Degree-2] The colored molded products prepared in the above Examples and Comparative Examples were placed in a 2 liter desiccator, and 200 ml of distilled water was poured into the desiccator.
Seal while exposed in ~ 80% atmosphere. that time,
Irradiate fluorescent light from above (Illumination of sample surface is about 2,000L
ux) and maintain at room temperature for 21 days. The yellowing degree (ΔY1) of the colored molded product is measured using a colorimetric color difference meter in accordance with JIS 7103 (Plastic yellowing degree and yellowing degree test method).

[0021]

[Table 1] Yellowness test result -1 of the examples (Yellowness evaluation method -1) *: Surface treated pearl pigment: Methyl hydrogen polysiloxane surface treated pearl pigment

[0022]

[Table 2] Yellowness test result-1 of Comparative Example (Yellowness evaluation method-1)

[0023]

[Table 3] Yellowness test result-2 of Example (Yellowness evaluation method-2) *: Surface treated pearl pigment: Methyl hydrogen polysiloxane surface treated pearl pigment

[0024]

[Table 4] Yellowness test result-2 of comparative example (Yellowness evaluation method-2)

[0025]

As described above, according to the present invention, by using the resin composition containing the weather-resistant pearlescent pigment of the present invention, it is possible to obtain a polyolefin resin colored molded article without yellowing.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI C09C 3/12 C09C 3/12 (58) Field surveyed (Int.Cl. ⁶ , DB name) C08L 1/00-101/14 C08K 3/00-13/08 C09C 1/00-3/12

Claims (2)

(57) [Claims] 1. 100 parts by weight of a resin and 0.5 of a pearlescent pigment
A resin composition comprising-20 parts by weight, wherein the pearlescent pigment is surface-coated with an alkylpolysiloxane having a reactive hydrogen, amino hydrogen group and / or halogen atom in the molecule. 2. The resin composition according to claim 1, wherein the resin is a polyolefin resin.