JPH04136076A - Preparation of coloring agent for polyolefin resin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a colorant for polyolefin resins using a styrene compound grafted polyolefin wax as a dispersant.

(Prior art) Conventionally, coloring agents for polyolefin resins such as polyethylene and polypropylene are mixed using polyolefin wax such as polyethylene wax as a dispersant and kneaded for a long time using a discontinuous kneading machine such as a kneader. It is manufactured by.

(Problem to be solved by the invention) However, polyolefin wax has high lubricity and the shear stress applied during kneading is low, so when a continuous kneading machine such as an extruder is used, the discharge rate decreases. Therefore, there were problems in that production efficiency was poor, and sufficient kneading was not possible, resulting in only a colorant with poor pigment dispersibility being obtained.

(Means for solving the problem) As a result of intensive research in view of the above situation, the present inventor has found that
When a styrene-based compound-grafted polyolefin wax is used as a dispersant, a coloring agent for polyolefin resins with better pigment dispersibility than before can be obtained when kneading with a discontinuous kneading machine, and when mixed with a continuous kneading machine The present inventors have discovered that when kneaded in a machine, a coloring agent for polyolefin resins with a high discharge rate, sufficient kneading, and excellent pigment dispersibility can be efficiently obtained, and the present invention has been completed.

That is, the present invention provides a method for producing a coloring agent for polyolefin resin in which a mixture containing a pigment and a dispersant is kneaded, which is characterized in that a styrene compound grafted polyolefin wax is used as the dispersant. A method for producing a coloring agent is provided.

Examples of the styrene compound-grafted polyolefin wax used in the present invention include polyolefin waxes grafted with styrene compounds, oxides thereof, oxidized polyolefin waxes grafted with styrene compounds, and polyolefin waxes grafted with styrene compounds. Examples include those obtained by graft polymerization of a styrene compound and an unsaturated carboxylic acid or a derivative thereof. It should be noted that the styrene compounds, unsaturated carboxylic acids, etc. used in the graft polymerization do not necessarily need to be all grafted onto the polyolefin wax, but may be partially mixed, for example, as polystyrene. It may be.

The polyolefin wax used here is, for example, one of olefins such as ethylene, propylene, butene-1, etc.
Examples include those formed by polymerizing one species or two or more species, and ethylene is usually used. Further, examples of the styrene compound include styrene, α-methylstyrene, P-methylstyrene, etc., and styrene is usually used. Furthermore, examples of unsaturated carboxylic acids or derivatives thereof include (meth)acrylic acid, crotonic acid, (anhydride)maleic acid, (meth)acrylic acid,
Examples include methyl acrylate, acrylonitrile, acrylamide, and the like.

The above-mentioned styrene-based compound grafted polyolefin wax preferably contains 10 to 40 parts by weight of styrene per 100 parts by weight of polyethylene wax having a molecular weight of 500 to 4,000.
It is preferable to graft-polymerize using 0 parts by weight of polyethylene wax, especially polyethylene wax having a molecular weight of 1000 to 2000.
It is preferable to carry out graft polymerization using 30 to 200 parts by weight of styrene to 00 parts by weight.

Further, as the melt viscosity of the above-mentioned styrene compound grafted polyolefin wax, one having a melt viscosity at 140°C of 1000 to 600 Qcps is usually used, and one of 3000 to 6000 cps is particularly preferred.

Examples of the pigment used in the present invention include organic pigments, inorganic pigments, extender pigments, and metal powders. Examples of organic pigments include azo pigments such as azo lake pigments, insoluble azo lake pigments, and condensed azo pigments; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; threnic pigments such as anthraquinone pigments, perinone pigments, and perylene pigments; quinacridone pigments; Examples include fused polycyclic pigments such as isoindolinone pigments and dioxazine pigments.

Inorganic pigments include, for example, titanium pigments such as titanium oxide and titanium yellow; iron oxide pigments such as Bengara and yellow iron oxide; chromate pigments such as yellow lead and chrome vermilion; aluminic acids such as cobalt blue. Examples include salt pigments and carbon black. Examples of extender pigments include calcium carbonate, alumina silicate, silica sand, calcium hydroxide, talc, clay, and mica. Furthermore, examples of the metal powder include brass powder, aluminum powder, and the like.

In order to obtain the polyolefin resin colorant by the production method of the present invention, for example, a styrene compound grafted polyolefin wax and a pigment are added, and if necessary, additives such as lubricants and stabilizers, other polyolefin waxes, polyolefin resins, etc. After mixing and kneading with a kneading machine, it may be pelletized or powdered.

Examples of the meat kneading machine used here include discontinuous kneading machines such as a kneader-Banbury mixer, continuous kneading machines such as a single-screw or multi-screw extruder, etc., but they are efficient and automated. A continuous kneading machine, especially a twin-screw extruder, is preferable because it is easy to save labor.

The proportion of the styrene compound-grafted polyolefin wax and the pigment varies greatly depending on the type of pigment, purpose of use of the colorant, application, etc., and is not particularly limited, but is usually 1 to 2000 parts by weight per 100 parts by weight of the styrene compound-grafted polyolefin wax. The range is preferably 40 to 200 parts by weight for organic pigments, and 100 to 500 parts by weight for other pigments.

The coloring agents of each color obtained by the manufacturing method of the present invention can be used as is as a masterbatch, for example, if they are in the form of pellets, but they can be mixed together to match the color and kneaded together with a diluted resin made of polyolefin resin. It is also possible to make a mask batch with toned colors.

In addition, the coloring agent obtained by the manufacturing method of the present invention that does not contain other polyolefin waxes and polyolefin resins other than the styrene compound grafted polyolefin wax, or contains only a small amount of these, is limited to polyolefin resins. It is also preferable because it can also be used as a coloring agent for aromatic polymers such as polystyrene, aromatic polycarbonate, and aromatic polyester.

(Example) The present invention will be specifically described below with reference to Examples and Comparative Examples. Note that parts and percentages in the examples are based on weight.

Example 1 Styrene-grafted polyethylene wax (1) (melt viscosity at 140°C by Brookfield viscometer: 4
000 cps, styrene content 60%) and 50 parts of phthalocyanine green were mixed in a high-speed mixer, and then kneaded in a twin-screw extruder heated to 120°C with a screw diameter of 65 m/m and a screw rotation speed of 20 Orpm. After extrusion, it was cut with a pelletizer to obtain a pellet-like color base (1), and its discharge amount was measured.

After mixing 50 parts of the obtained color haze (1) with 50 parts of low-density polyethylene (density 0.920 g/cil), Melt Inde Nox 3 g/10 m1n, in a tumbler, the mixture was heated to 140°C using a screwdriver. Diameter 4
After kneading and extruding with a single-screw extruder with 0ffl/ra and a screw rotation speed of 150 rpm+, the mixture was canted with a pelletizer to obtain pelletized master hatch (1).

4 parts of this master haunch (1) and 9 parts of low-density polyethylene
6 parts were mixed in a tumbler and kneaded for 5 minutes using two rolls with a diameter of 6 inches heated to 150°C to form a green sheet with a thickness of 11. This sheet was then used to evaluate pigment dispersibility. The area index and maximum particle diameter were determined as follows. The results are shown in Table 2.

About 1 mg of sample was cut from the obtained sheet, placed on a slide glass, and a cover glass was placed on top.
After hot pressing at 0°C to form a film with a thickness of 15 to 20 μm, select the field of view with the worst dispersion using a 100x optical microscope, and determine the particle size of particles with a particle size of 11 μm or more within this field of view. The number of particles corresponding to the particle size range shown in Table 1 is multiplied by the representative area index, and then summed.
The evaluation was carried out on several samples, and the average of the total was taken as the area index of the colorant. Moreover, the diameter of the largest particle observed in the five samples mentioned above was defined as the maximum particle diameter. However, particles with a particle size of 10 μm or less were excluded.

Table 1 Example 2 Styrene grafted polyethylene wax (2) (melt viscosity at 140°C measured by Brookfield viscometer: 2000 cps, styrene content 60%) was used instead of styrene grafted polyethylene wax (1). Other than that, the discharge amount was measured in the same manner as in Example 1, and the thickness was measured using the pellet-shaped color base (2), the mask-haunch (2), and the 8cm masterbatch (2).
A green sheet of +ms was obtained, and then the area index and maximum particle size were determined in the same manner. The results are shown in Table 2.

Example 3 In the same manner as in Example 1, except that 30 parts of styrene-grafted polyethylene wax (1) and 70 parts of titanium oxide were used instead of 50 parts of styrene-grafted polyethylene wax (1) and 50 parts of phthalocyanine green. While measuring the discharge amount, the pellet color base (3) and masterbatch (3), and the masterbatch (3)
) was used to obtain a white sheet with a thickness of 1 mm, and then the area index and maximum particle diameter were determined in the same manner. Table 2 of the results
Shown below.

Example 4 After mixing 90 parts of styrene-grafted polyethylene wax (1) and 10 parts of phthalocyanine green in a Henschel mixer, the mixture was kneaded and extruded in a twin-screw extruder with a screw diameter of 65+n/m and a screw rotation speed of 200 rpm.
The pelletized master hatch (4) was obtained and the discharge amount thereof was measured.

Next, 10 parts of this master haunch (4) and 90 parts of low-density polyethylene were mixed in a tumbler, and then heated at 150°
After kneading for 5 minutes with two rolls heated to C, it becomes 1 liter thick.
A green sheet of llI+ was prepared, and then the area index and maximum particle size were determined in the same manner as in Example 1.

The results are shown in Table-2.

Comparative Example 1 Polyethylene wax (1') instead of styrene-grafted polyethylene wax (1) (melt viscosity at 140°C by Brookfield viscometer: 4000 cps)
), except that the discharge amount was measured in the same manner as in Example 1, and the pellet-like color base (l") and masterbatch (1'), as well as the master bunch (1') were used.
A green sheet with a thickness of III was obtained using the same method, and the area index and maximum particle size were determined in the same manner. Display the results -
Shown in 2.

Example 5 Styrene grafted polyethylene wax (1) 25 kg
and 25 kg of phthalocyanine green were put into a 100 f kneader, mixed for 10 minutes, and heated at 100°C.
After kneading for 0 minutes and cooling kneading for 15 minutes, it was passed twice through three rolls with a diameter of 16 inches heated to 120°C.
Next, it was ground with a rotary cutter type grinder to obtain a powdered color base (5).

Next, Example 1 except that this color base (5) was used.
A pelleted master bunch (5) and a green sheet with a thickness of 1 mm were obtained in the same manner as above, and then the area index and maximum particle size were determined in the same manner. The results are shown in Table 2.

Comparative Example 2 Powdered color base (2゛) was obtained in the same manner as in Example 5, except that polyethylene wax (1゛) was used instead of styrene-grafted polyethylene wax (1), and then pellets were obtained in the same manner as in Example 1. Master hatch (2
'') and a green sheet with a thickness of 1 m were obtained, and then the area index and maximum particle size were determined in the same manner.The results are shown in Table 2.
Shown below.

(Effects of the Invention) According to the production method of the present invention, a colorant for polyolefin resins having excellent pigment dispersibility can be obtained. Furthermore, if a continuous kneading machine such as an extruder is used as the kneading machine, a coloring agent for polyolefin resins having excellent pigment dispersibility can be obtained more efficiently, and in this case, automation and labor saving are easy.

Claims (1)

[Scope of Claims] 1. A method for producing a colorant for a polyolefin resin by kneading a mixture containing a pigment and a dispersant, characterized in that a styrene compound grafted polyolefin wax is used as the dispersant. Manufacturing method of colorant for resin. 2. The manufacturing method according to claim 1, wherein the blend is continuously kneaded using a continuous kneader. 3. The manufacturing method according to claim 2, wherein the continuous kneading machine is a twin screw extruder. 4. The method according to claim 1, 2 or 3, wherein the styrene compound grafted polyolefin wax is a styrene grafted polyolefin wax. 5. The method according to claim 1, 2 or 3, wherein a polyolefin is used in combination with the pigment and the dispersant. 6. The method according to claim 5, wherein the dispersant is styrene-grafted polyethylene and the polyolefin is polyethylene.