JPH04372632A - Colorant for polyolefin resin and polyolefin resin colored therewith - Google Patents

Abstract

PURPOSE:To obtain a colorant which can give a colored product of excellent dimensional stability by using a pigment having a specified specific surface area, represented by a specified structural formula and obtained by heating a diketopyrrolopyrrole pigment in an aprotic polar organic solvent. CONSTITUTION:This colorant comprises a pigment having a specific surface area of 3-15m<2>/g, represented by the structural formula (wherein X is H or C1) and obtained by heating a diketopyrrolopyrrole pigment {e.g. 3,6-bis(4- chlorophenyl)-1,4-diketopyrrolo[3,4-c]pyrrole} in an aprotic polar organic solvent (e.g. N,N-dimethylformamide).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coloring agent for resins and colored resin products colored with the coloring agent. More specifically, the present invention relates to a colorant for polyolefin resin containing a diketopyrrolopyrrole pigment and a colored product colored with the colorant for polyolefin resin.

0002

[Prior Art] Conventionally, polyolefins have been used in a wide range of fields as general-purpose synthetic resins, and in many cases, various colors have been added to increase their commercial value, but the addition of pigments has affected their dimensional stability during molding. known to be inhibited. Polyolefin resins tend to crystallize during molding,
As a result, the molded product not only shrinks, resulting in a smaller finished size, but also has different shrinkage properties depending on the direction of the flow of the molten resin (shrinkage anisotropy), causing distortion and distortion. Such a phenomenon becomes noticeable when an organic pigment is used as a coloring agent, and improvement thereof is desired.

[0003] The cause of this inhibition of dimensional stability when organic pigments are used as colorants has not yet been completely elucidated, but it is thought to be caused by the particle shape, crystal form, surface condition, etc. It is being It is well known that the pigment represented by formula (1) below is useful as a bright red organic pigment with excellent resistance such as heat resistance, light resistance, weather resistance, and migration resistance, and is used in the paint field. Although it is widely used, it is not often used as a coloring agent for polyolefin resins because it has the above-mentioned disadvantages peculiar to organic pigments.

[0004] Up to now, several methods have been proposed for improving the dimensional stability of resin molded articles when organic pigments are used as colorants by changing the form of the organic pigments. That is, (1) A method of coating the pigment surface with another substance. For example, a method of adding a modifier such as organic silane to surface-treat the pigment (Japanese Patent Publication No. 3-16379) (2) A method of changing the crystal form of the pigment. A method that attempts to suppress the effect on shrinkage by changing the surface properties by changing the crystal form of the pigment (Japanese Patent Publication No. 62-37053, Japanese Patent Publication No. 1)
-38417) (3) Method of changing the size of pigment particles. There is a method of controlling the function of a pigment as a crystal nucleus by changing the size of pigment particles (Japanese Patent Publication No. 62-4417).

However, in method (1), the modifier used must not have a negative effect on light resistance, heat resistance, etc. From this point of view, treatment with an inorganic substance is preferable, but treatment with an organic substance is preferable. Coating pigments with inorganic substances is technically very difficult. Method (2) is
Although this method provides a crystalline pigment that does not easily cause deformation of resin molded articles and is a practical method, it cannot be applied to pigments that have a stable crystalline form where no change in crystalline form is found. Method (3) is a method of controlling the function of organic pigment particles as crystal nuclei in the resin to improve shrinkage.

[0006]

Problems to be Solved by the Invention There is a need for the development of a form of a diketopyrrolopyrrole pigment that will not cause shrinkage of resin moldings when used for coloring polyolefin resins.

[0007]

[Means for Solving the Problems] The present inventors have determined the size, shape, crystal form, etc. of diketopyrrolopyrrole pigments, and the dimensions of polyolefin resin molded products colored with colorants containing these pigments. The present invention was developed as a result of intensive research into the relationship with stability. That is, the present invention (1)
Formula (1) obtained by heat treating a diketopyrrolopyrrole pigment in an aprotic polar organic solvent

[0008]

[Chemical 2]

A coloring agent for polyolefin resins containing a diketopyrrolopyrrole pigment having a specific surface area of 3 to 15 m 2 /g (wherein X represents a hydrogen atom or a chlorine atom). (2) Synthesis of the diketopyrrolopyrrole pigment without isolating it from the reaction solution; after exchanging the diketopyrrolopyrrole pigment with a solvent system mainly consisting of an aprotic polar organic solvent in the same reaction bath, the above-mentioned pigment is heated to It has the formula (1) and has a specific surface area of 3 to 15 m
2/g of a diketopyrrolopyrrole pigment. (3) A colored polyolefin resin product colored with the colorant for polyolefin resin according to the above item 1 or claim 2.

The present invention will be explained in detail. Specific examples of the aprotic polar organic solvent used in the heat treatment of the diketopyrrolopyrrole pigment in the present invention include N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N,N'-dimethyl- Examples include 1,3-imidazolidine-2-one, dimethyl sulfoxide, etc., but considering operability, safety, boiling point, etc., N, N
-dimethylformamide is most preferred. These may be used alone or in combination of two or more. Further, these may be used in combination with water, an aqueous inorganic salt solution, an aqueous organic salt solution, or the like. The amount of the solvent to be used is 1 to 50 times, preferably 3 to 20 times the weight of the pigment to be treated. The treatment temperature depends on the boiling point of the organic solvent used, but
℃ to 180℃, preferably 100℃ to 160℃
It is ℃. Processing time is usually 1 to 10 hours.

Generally, diketopyrrolopyrrole pigments contain 1
It is obtained by reacting mol of succinic acid diester and 2 mol of benzonitriles in a tertiary alcohol in the presence of a strong base, then hydrolyzing the reaction product with water or acid, and isolating it by a conventional method ( Japanese Patent Publication No. 58-210084
, JP-A-64-42482), the diketopyrrolopyrrole pigment used in the present invention may be in various forms such as a dry bulk powder, a wet cake, or a synthetic reaction solution after hydrolysis. In particular, a method in which diketopyrrolopyrrole pigments are heat-treated after being solvent-exchanged to an aprotic polar solvent as described above in the same reaction bath without isolating the diketopyrrolopyrrole pigment from its synthesis reaction solution is It is possible to omit the steps such as filtration and drying that occur in the process, and it is economically very advantageous for industrialization.

[0012] Solvent exchange is carried out in a conventional manner. In the present invention, the pH of the synthesis reaction solution after the above hydrolysis is set to 3.
to 11, then introduce water vapor into the reaction vessel at 80°C to 100°C to remove alcohol from the reaction system, and then add an aprotic polar solvent such as N,N-dimethylformamide into the reaction vessel. I will do it. The diketopyrrolopyrrole pigment used in the present invention may have a single structure or may be a mixture of two or more pigments. In particular, 1 mole of succinic acid diester is mixed with 1 mole of 4-chlorobenzonitrile.
Particularly remarkable effects are obtained when using a diketopyrrolopyrrole pigment obtained by reacting with 2 to 1.8 mol of benzonitrile and 0.8 to 0.2 mol of benzonitrile, and then hydrolyzing the reaction product. be found.

That is, by changing the ratio of 4-chlorobenzonitrile and benzonitrile used, it is possible to control the crystal form of the resulting pigment mixture, and to create a crystal form that does not easily cause deformation of the colored polyolefin resin molded product. pigments can be provided. It is known that 1,4-diketo 3,6-diphenylpyrrolo[3,4-C]pyrrole pigment has plate-shaped crystals (Japanese Patent Laid-Open No. 3-52996). On the other hand, 1,4-diketo 3,6-bis(4-chlorophenyl)pyrrolo[3,4-C]pyrrole pigment heat-treated in N,N'-dimethylformamide shows mainly hexagonal crystals when observed with an electron microscope. It had However, crystals of the pigment mixture isolated from the synthetic reaction solution obtained by reacting 1 mole of succinic diester with 1.6 moles of 4-chlorobenzonitrile and 0.4 moles of benzonitrile and then hydrolyzing the reaction products. The shape was a crystalline shape similar to a rectangular parallelepiped.

On the other hand, the isoindolinone pigment, which is known as a pigment that tends to cause deformation of polyolefin resin molded products when colored, like the diketopyrrolopyrrole pigment, has a rectangular crystal shape that improves the shrinkage anisotropy. It is known (Japanese Unexamined Patent Publication No. 1-38417) that the shrinkage anisotropy of diketopyrrolopyrrole pigments can be significantly improved by heat-treating them with an aprotic polar solvent and converting them into pigments with a specific specific surface area. I was able to do that. The colorant for polyolefin resins of the present invention is 0.05 to 1.0 times the weight of the diketopyrrolopyrrole pigment having a specific surface area of 3 to 15 m2/g obtained as described above, preferably 0.1 ~0
．． Prepared by mixing 5 times the weight of metal soap. Specific examples of metal soaps that can be used include magnesium stearate, zinc stearate, and the like. In order to improve the hue, physical strength, and durability of the molded product, the colorant for resins of the present invention may contain other commonly used pigments and various additives, such as surfactants, to improve the hue, physical strength, and durability of the molded product. It can be used in combination with additives, plasticizers, dispersants, antistatic agents, antioxidants, ultraviolet absorbers, etc., and can also be used by kneading it with colored resins, low molecular weight polyethylene, polypropylene, etc. You can also do it. Therefore, the colorant according to the present invention can be in the form of powder, granules, pellets,
It is used in various forms such as beads, flakes, and paste.

The coloring agent for resins of the present invention can be conveniently used for coloring various resins, but in particular polyolefins such as polyethylene and polypropylene, which have shrinkage anisotropy and poor dimensional stability, and ethylene or propylene and vinyl chloride. It is conveniently used for coloring polyolefin resins obtained by copolymerizing , vinyl acetate, acrylonitrile, etc., and has the characteristic that it does not impair dimensional stability. Conventional methods can be used to color these resins. For example, prior to injection molding of the resin, 0.05 to 0.5% by weight of the colorant of the present invention is added and kneaded to resin powder or pellets. According to the present invention, a colored molded resin product with small shrinkage anisotropy and excellent dimensional stability can be obtained. The red colored resin or red colored resin molded product obtained by the present invention has excellent properties such as weather resistance and heat resistance, as well as excellent dimensional stability, so it can be used in applications requiring these properties, such as engineering plastics. It can be conveniently used as a service.

[0016]

[Examples] The present invention will be further explained in detail with reference to the following examples. In the examples, all percentages and parts are by weight.

Example 1 20 parts of 3,6-bis(4-chlorophenyl)-1,4-diketopyrrolo[3,4-C]pyrrole prepared by a known method were suspended in 100 parts of N,N-dimethylformamide. Make it cloudy and raise the temperature to 140℃, 140-145℃
After stirring for 6 hours, the mixture was cooled to 120-125°C and filtered at the same temperature. The filtered product was washed successively with N,N-dimethylformamide and water and dried to obtain 19.6 parts of a red pigment. The specific surface area (BET method) of this pigment is 8.8 m2/
It was g. 8.0 parts of magnesium stearate was added and mixed to obtain the colorant for resin of the present invention.

Example 2 3,6-bis(4-chlorophenyl)-1, produced by a known method (Example 1 of JP-A-64-42482)
The temperature of the synthesis reaction solution containing 27 parts of 4-diketopyrrolo[3,4-C]pyrrole was set to 50°C, and after neutralization with sulfuric acid,
The temperature was raised to 85°C. Next, while introducing water vapor into the reaction vessel, the temperature was gradually raised to 100°C, and the alcohol content was distilled off. 200 parts of N,N-dimethylformamide was added to the remaining aqueous suspension, and the temperature was raised to 140° C. while distilling off the distillate, followed by stirring at 140 to 145° C. for 10 hours. Thereafter, it was cooled to 120-125°C and filtered at the same temperature. The filtered product was washed successively with N,N-dimethylformamide and water and dried to obtain 26.8 parts of a red pigment. The specific surface area (BET method) of this pigment was 10.1 m2/g. 10.9 parts of magnesium stearate was added and mixed to obtain the colorant for resin of the present invention.

Example 3 Under an inert gas atmosphere, 11.0 parts of 4-chlorobenzonitrile and 2.0 parts of benzonitrile were added to a solution of 14.4 parts of sodium tert-butyrate suspended in 40 parts of tertiary amyl alcohol. 1 part was added and the resulting mixture was heated to 85°C. Next, a solution of 10.1 parts of diisopropyl succinate mixed in 10 parts of tertiary amyl alcohol was added dropwise at 85 to 95°C over 80 minutes, and further added at the same temperature for 2 hours.
Stir for hours. Approximately half of the resulting pyrrolopyrrole sodium salt suspension was poured into 27 parts of water and stirred under reflux for 8 hours. The remainder of the above sodium salt suspension was then added at 85° C. and the resulting suspension was stirred under reflux for 1 hour. Next, while introducing water vapor into the reaction vessel, the temperature was gradually raised to 100°C to distill off the alcohol content. continue,
The entire amount of the wet cake was added and suspended in 100 parts of N,N-dimethylformamide, and the temperature was raised to 140°C.
Stirred at 140-145°C for 6 hours. Then 120-1
It was cooled to 25°C and filtered at the same temperature. The filtered product is N
, N-dimethylformamide and water and dried to obtain 11.1 parts of a red pigment. The specific surface area of this pigment (
BET method) was 7.3 m2/g. 4.5 parts of magnesium stearate was added and mixed to obtain the colorant for resin of the present invention.

Examples 4 to 6 (Deformability test) High-density polyethylene (manufactured by Mitsui Petrochemical Co., Ltd.)
HIZEX 2200J) was used as the colored resin, 0.2% of each of the resin colorants of the present invention obtained in Examples 1, 2, and 3 was added thereto, blended using a blender, and then injection molded. The molded product was molded using a machine (Yamashiro SVA-30A, screw in-line), and the deformability of the molded product was determined. Molding conditions are injection temperature 200℃, injection pressure 16K.
g/cm2, injection time 7 seconds, mold temperature 40°C, cooling time 20 seconds, and the molded product was left for one day after being taken out. The mold was disc-shaped, with a diameter of 70 mm and a thickness of 2 mm, and the molten resin was injected from the center of the disc. The obtained disc-shaped molded product was placed on a flat surface, one corner of the disc was lightly pressed, and the height (mm) from the flat surface at which the warp on the opposite side was maximum was defined as the degree of deformation. The results are shown in Table 1.

Comparative Example 1 A resin was molded using the same high-density polyethylene as used in Examples 4 to 6 without using a pigment, and the degree of deformation was measured in the same manner as in Examples 4 to 6. . The results are shown in Table 1.

Comparative Example 2 High-density polyethylene similar to that used in Examples 4 to 6 was coated with 3,6-bis(4-chlorophenyl)-1,4-diketopyrrolo[3,4-C]pyrrole (JP-A-64 -424
82 Synthesis based on Example 1) Add 4.5 parts of magnesium stearate to 10 parts to obtain a resin colorant, add 0.2% of the colorant, and use the same method as in Examples 4 to 6. The degree of deformation was measured. The results are shown in Table 1.

[0023]

[Table 1]

From the results in Table 1, it is clear that the resin colorants of the present invention obtained in Examples 1, 2, and 3 show a degree of deformation close to that of the blank test, and provide colored resin products with excellent dimensional stability. It is.

Example 7 In Example 1, N,N'-dimethyl-1,3-imidazolidine- was used instead of N,N-dimethylformamide.
A heat-treated pigment was obtained in the same manner as in Example 1 except that 2-one was used. The specific surface area (BET method) of this pigment is 7.3
m2/g. To this, 4.5 parts of zinc stearate was added and mixed to obtain a coloring agent for resins of the present invention.

[0026]

Effects of the Invention By coloring with a coloring agent containing a diketopyrrolopyrrole pigment having a specific specific surface area according to the present invention, a colored polyolefin resin product having a small degree of deformation and excellent dimensional stability can be obtained.

Claims (3)

[Claims] Claim 1: Formula (1) obtained by heat-treating a diketopyrrolopyrrole pigment in an aprotic polar organic solvent: (wherein, X represents a hydrogen atom or a chlorine atom) A coloring agent for polyolefin resins containing a diketopyrrolopyrrole pigment having a specific surface area of 3 to 15 m2/g. [Claim 2] A diketopyrrolopyrrole pigment is obtained by solvent exchange into a solvent system mainly consisting of an aprotic polar organic solvent in the same reaction bath without isolating it from its synthesis reaction solution, followed by heat treatment. A coloring agent for polyolefin resins, which has the formula (1) according to claim 1 and contains a diketopyrrolopyrrole pigment having a specific surface area of 3 to 15 m2/g. 3. A colored polyolefin resin product colored with the colorant for polyolefin resin according to claim 1 or 2.