JP3180606B2 - Methyl hydrogen polysiloxane-treated titanium oxide-containing colorant composition and molded article thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyolefin molded article,
In particular, the present invention relates to a colorant composition suitable for coloring a thin film such as a polyolefin film or sheet. More specifically , the present invention contains titanium oxide subjected to a specific surface treatment, dispersibility,
Polyolefin colorant composition may form an excellent molded article yellowing resistance and its moldings.

[0002]

2. Description of the Related Art Hitherto , polyolefin molded articles have been colored using a coloring composition containing titanium oxide treated with a surface treating agent other than methyl hydrogen polysiloxane. Examples of the coloring molding method include extrusion molding and injection molding, and films, sheets, blow bottles, and various molded products are widely and generally provided.

[0003]

Generally, titanium oxide used for coloring a polyolefin resin is subjected to a surface treatment. This surface treatment is inorganic treatment
(Alumina, silica, titania, zirconia) and organic processing
(Polyols, silicones). Polio
Dispersibility of titanium oxide in refining resin is
Although improvement in the process Me sure, polyolefin colored moldings
It was a disadvantage that the yellowing of the powder could not be prevented.

[0004] In general the various phenol derivatives as stabilizers antioxidants to prevent the oxidation of the polyolefin resin is added. However, it is said that when the phenol derivative in the antioxidant is added to the polyolefin, it binds to the active sites on the surface of the titanium oxide to produce a yellow-yellow-brown substance, which causes yellowing of the plastic . Also, when left in a dark place for a long time irrespective of the presence of titanium oxide, it is supplied with oxygen and automatically oxidized to red quinone to exhibit a pink color. In the presence of nitrogen oxides, phenolic stabilizers can form tan nitrosophenols and yellow the polyolefin resin.

Accordingly, an object of the present invention is to provide a polyolefin colorant composition which can prevent yellowing of a molded article even when left for a long period of time and which has both high dispersibility and a molded article using the same.

[0006]

SUMMARY OF THE INVENTION The present invention provides an organic surface treatment.
Oxide treated with the agent methyl hydrogen polysiloxane
Emissions, a dispersing agent and polyolefin colorant composition characterized by containing a polyolefin resin and a molded article formed by using the same. The present inventors have repeatedly studied the formulation of a colorant that prevents discoloration and high dispersibility in a polyolefin resin, and as a result, by coloring the polyolefin resin with a titanium oxide pigment treated with methyl hydrogen polysiloxane, The inventors have found that both dispersibility and yellowing resistance can be achieved, and completed the present invention.

[0007] To explain the invention in detail, used in the present invention
The polyolefin resin to be obtained is a conventionally known resin.
Polyethylene is low-density, medium-density, and high-density polyethylene, and polypropylene is homo-, block-, or random polypropylene, and other thermoplastic resins containing these as main components and mixtures thereof. The titanium oxide used in the present invention has a particle size distribution of 0.05 to 0.45 μm and an average particle size of 0.20.
It is a rutile type titanium oxide of about 0.30 μm. The methyl hydrogen polysiloxane used in the present invention is shown below.
Containing Si—O bonds (siloxane bonds).

[0008]

Embedded image

(Where n represents a positive integer) n is 12
The following is preferred. The surface treatment amount of methyl hydrogen polysiloxane to titanium oxide is preferably 0.01 to 5 parts by weight. Particularly preferred is 0.1 to 3 parts by weight. If the surface treatment amount exceeds 5 parts by weight , the dispersion of titanium oxide is inhibited, and
If the amount is less than 0.01 part by weight, the effect of the present invention is not exhibited. Met
Titanium oxide surface-treated (coated) with hydrogen siloxane
Uses titanium oxide particles as a micronizer and jet mixer.
When grinding with a fluid energy grinder such as
Obtained by adding hydrogen polysiloxane.

[0010] The surface treatment can also be carried out by mixing uniformly using a high shear mixer such as a Hensyl mixer or a super mixer. The mixing ratio of the colorant composition is 0.01 to 40 parts by weight of titanium oxide per 100 parts by weight of the polyolefin resin.
0 parts by weight. Dispersing agent used in the present invention include polyethylene wax, low molecular weight polypropylene wax waxes and metal soaps, and the like. The low molecular weight wax is preferably 0 to 10 parts by weight in the colorant composition, and the metal soap is preferably 0 to 5 parts by weight.

The polyolefin colorant composition of the present invention may contain, if necessary, known additives such as other pigments and ultraviolet absorbers in addition to the above-mentioned components.

[0012]

The present invention will be described below in detail with reference to examples and comparative examples. Yellowing evaluation method (1) Black lamp according (to evaluate Place sample injection plate black lamp under 20cm of 20w having a wavelength region of 300 nm to 400 nm.) Yellowing Example 1 or ratio
10 black lamps were applied to the press sheet created in Comparative Example 1.
After irradiation for one day, the yellowing degree of the pressed sheet was measured by a color difference (ΔE) using a colorimeter. (2) Yellowing by high-temperature and high-humidity method After leaving for 96 hours in an environment of 80 ° C. and 100% RH, yellowing was measured by a color difference meter in the same manner as in (1).

Example 1 100 parts by weight of polyethylene resin (specific gravity 0.957, MFR 6.0 g / 10 min), 0.4 part by weight of titanium oxide pigment (methyl hydrogen polysiloxane content 0.11%), and polyethylene wax (molecular weight 4300, specific gravity 0.924) 0.1 parts by weight, BHT
(2,6-di-tert-butyl-4-methylphenol)
After kneading 0.1 part by weight with two rolls, a 1 mm thick press sheet was prepared and evaluated by the above evaluation methods (1) and (2). Comparative Example 1 100 parts by weight of polyethylene resin (specific gravity 0.957, MFR 6.0 g / 10 min), 0.4 parts by weight of titanium oxide pigment (not treated with methyl hydrogen polysiloxane), and 0.1 part by weight of polyethylene wax (molecular weight 4300, specific gravity 0.924) , BHT
Evaluation was made in the same manner as in the examples at 0.1 parts by weight.

[0014]

[Table 1]

Dispersibility evaluation method Labo Plastomill (manufactured by Toyo Seiki) 50 rpm, screen
Mesh 40/80/120/500, temperature 300 ° C
, High density polyethylene (specific gravity 0.958, MFR 0.4g / 10mi
n) After measuring the resin pressure (P ₁ ) after passing through
The colorant set prepared in Example 2 or Comparative Example 2 below
After passing 600 g of the product,
Measure the resin pressure (P ₂ ) when passing through the
The value obtained by subtracting the P ₁ from ₂ and resin pressure difference and ([Delta] P). That is, it can be said that the smaller the value of ΔP, the better the dispersibility of titanium oxide.

Example 2 29 parts by weight of low-density polyethylene (specific gravity 0.917, MFR 7.2 g / 10 min), polyethylene wax (molecular weight 4300, specific gravity 0.924)
) 10 parts by weight, 1 part by weight of metal soap, and 60 parts by weight of titanium oxide (polysiloxysan methylhydrogen content: 0.11%) were dry-blended with a Henschel mixer, and then a masterbatch was obtained with a twin-screw extruder. Thereafter, the dispersibility was evaluated by the above evaluation method. Comparative Example 2 29 parts by weight of low-density polyethylene (specific gravity 0.917, MFR 7.2 g / 10 min), polyethylene wax (molecular weight 4300, specific gravity 0.924)
10 parts by weight, metal soap 1 part by weight, titanium oxide (not treated with methyl hydrogen polysiloxysan)
Evaluation was performed in the same manner as in the examples at 60 parts by weight.

[0017]

[Table 2]

[0018]

By using the colorant composition of the present invention, it is possible to obtain a polyolefin colored molded article having high dispersion and no yellowing. Particularly, molded articles such as films and sheets require extremely high dispersibility and yellowing resistance, and therefore, the polyolefin colorant composition obtained by the present invention is useful.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-261164 (JP, A) JP-A-6-313114 (JP, A) JP-A-4-202476 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08L 23/00-23/36 C08K 3/00-13/08 C09C 1/36 C09C 3/12

Claims (3)

(57) [Claims] 1. A polyolefin colorant composition comprising titanium oxide treated with methyl hydrogen polysiloxane and a polyolefin resin. 2. The polyolefin resin is polyethylene, or
Characterized by at least one selected from polypropylene
Polyolefin colorant composition. 3. The polyolefin coloring according to claim 1 or 2.
Molded article using the agent composition.