JPH0759638B2 - Method for coloring polyamide resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Prior Art Polytetramethylene adipamide resin (nylon 46 resin)
Has a good affinity with various pigments and can be beautifully colored, so when used in large quantities as electric parts and automobile parts, most of them are colored and used.

On the other hand, in order to obtain a molded article by coloring an aliphatic polyamide resin such as conventional nylon 6, nylon 66 or nylon 46, a colorant and a fine powder such as a dispersion aid are almost uniformly dispersed in the polyamide resin. It was carried out by a method in which a colored molded product was obtained by molding using so-called colored pellets which were kneaded and pelletized by a post-extruder.

However, recently, in order to rationalize the coloring process, a dry coloring method, a liquid coloring method, or a granular coloring method in which a natural colored pellet of polyamide resin is directly blended with a dry color or a liquid color or a granular color as a colorant The color concentrate method in which a color concentrate composition containing a coloring agent and a coloring dispersion aid in a high concentration is prepared, and this is diluted to a constant color concentration has come to be used.

However, such a dry coloring method mixes a coloring agent directly, so that the coloring cost is low, but the dry color such as dyes and pigments (dye / pigment) is scattered, which causes pollution of the workplace and is not preferable from the environmental aspect.

Further, this method also has a drawback in that heat is directly applied to the dry color at the time of coloring and molding, and the dyes and pigments are re-aggregated to cause poor dispersion.

Further, the liquid coloring method does not have scattering properties such as dyes and pigments, but since a high boiling point organic solvent is used, silver streak easily occurs during coloring and molding, and physical properties,
In particular, it had drawbacks such as reduced heat resistance.

Further, the granular coloring method has no scattering property or stain resistance of dyes and pigments, but the cost of the colorant is higher than that of the dry color method, and moreover, the granular color slips at the time of coloring and molding to cause color unevenness. It has a defect that molding conditions are restricted such as appearance failure.

On the other hand, the color concentrate method has recently attracted attention as an alternative method to the above three coloring methods, but the coloring cost is higher than that of the colored pellet method, but it is found in the dry color method, the liquid color method and the granular color method. Natural pellets of various polyamide resins with one color concentrate, with no scattering and staining properties of dyes and pigments, good workability, no deterioration in appearance such as color unevenness and no deterioration in physical properties such as heat resistance. Since it can be colored, it has been widely used because it has advantages such as easy inventory management.

In recent years, polyamide resins have come to be used in a wide range of applications, paying attention to their excellent performance, and molded products such as injection molding are required to have a large size or a complicated structure. Polyamide resin colored by the conventional color concentrate method against polyamide resin molded under such severe molding conditions causes appearance defects such as color unevenness and dispersion failure in the molded product, which is actually industrially There was a problem to use.

Further, conventional polyamide resin color concentrate compositions have color unevenness, and the improvement of poor dispersion can be improved by adding various additives such as metallic soap and surfactants to the color concentrate composition. However, this method is not sufficient for practical use due to the remarkable occurrence of color unevenness and poor dispersion in the colored molded product, especially under high molding conditions where the dilution ratio is high. It was hard to say.

b. Problems to be Solved by the Invention In view of the above problems, the present invention is a colored molding without color unevenness or dispersion failure by simply adding additives to the polyamide resin color concentrate composition or changing the combination of additives. Instead of trying to obtain a product, a polyamide resin of a base material used for the color concentrate composition is selected to have a specific relative viscosity, and further, the relative viscosity of the color concentrate composition and the color of nylon 46 It is intended to provide a method for coloring a polyamide resin, which keeps the relationship with the relative viscosity constant and does not cause color unevenness or dispersion failure of a colored molded product even under severer molding conditions than the conventional color concentrate method.

c. Means for Solving Problems The present invention provides a color concentrate composition comprising a polyamide resin as a base material and a colorant uniformly mixed therein.
In the method of coloring by mixing with polytetramethylene adipamide resin, the relative viscosity of the base material (97% sulfuric acid 100 m
An aqueous solution of 1 g of the polymer in l is measured at 30 ° C) ηc is 2.5 to 4.
5 and the relative viscosity (measured under the same conditions as the base material) ηa of the polytetramethylene adipamide resin is such that the ratio of the two is ηa / ηc = 1.05 to 1.25. A coloring method is provided.

Hereinafter, the present invention will be described in detail.

Examples of the polyamide resin that is the base material of the color concentrate composition of the present invention include nylon 6,6 and nylon.
6,10, nylon 6,12, nylon 4,6, nylon 3,4, nylon 6,9, nylon 6, nylon 12, nylon 11, nylon 4 and the like. Also nylon 6 / 6,10, nylon 6/6,
12, nylon 6 / 4,6, nylon 6/12, nylon 6 / 6,6, nylon 6 / 6,6 / 6,10, nylon 6 / 4,6 / 6,6, nylon 6 / 6,6
Copolyamides such as / 6,12, nylon 6 / 4,6 / 6,10 and nylon 6 / 4,6 / 12 are also used.

Furthermore, semi-aromatic polyamides obtained from aromatic dicarboxylic acids such as nylon 6/6, T (T: terephthalic acid component), terephthalic acid, isophthalic acid and metaxylenediamine or alicyclic diamine, and metaxylenediamine and the above Mention may be made of polyamides, polyester amides, polyether amides and polyester ether amides obtained from linear carboxylic acids.

These can be used alone or in combination of two or more.

Polyamide resins that are preferable base materials are nylon 6, nylon 66, and nylon 4,6, and nylon 6 and nylon 6,6 are particularly preferable.

The main component of the color concentrate composition is composed of a base material made of polyamide resin, a coloring material and a coloring dispersant.

The amount of the base material used in the color concentrate composition is preferably 19.9 to 80% by weight, more preferably 29.5 to 77% by weight.
Is.

Examples of colorants include organic pigments, inorganic pigments, dyes, etc.
They can be used alone or in combination.

The amount of the colorant used in the color concentrate composition is preferably 1 to 80% by weight, more preferably 5 to 7% by weight,
Particularly preferably, it is 10 to 70% by weight. If it is less than 5%, the colorability is poor, while if it exceeds 80% by weight, the dispersibility is deteriorated due to the secondary aggregation of the colorant, which is not preferable.

Coloring dispersants are those which aid the dispersibility of colorants, for example zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, fatty acid salts such as metal stearate such as barium stearate, methylenebisstearylamide, Examples thereof include fatty acid amides such as ethylenebisstearylamide.

The amount of the color dispersant used in the color concentrate composition is preferably 0.1 to 5% by weight, preferably 0.5 to 15% by weight.
Is.

Relative viscosity of base material ηc (1g of polymer in 100ml of 97% sulfuric acid)
The solution is 2.5-4.5, preferably 2.6-4.0. Both less than 2.5 and more than 4.5 are not preferable because the color unevenness and poor dispersion are insufficiently improved.

Next, the colored nylon 46 will be described.

Nylon 46 to be colored by the process of the present invention is a polyamide consisting essentially of the following formula _{[NH-CH 2) 4 -NH-} CO- (CH 2) 6 -CO ] repeating structural unit represented by. The manufacturing method thereof is described in, for example, JP-A-56-1494.
The methods described in No. 30, No. 56-149431, No. 58-83029, No. 60-28843 and the like can be mentioned.

Further, in order to obtain the resin composition according to the present invention, a relative viscosity of 3.0 or more, preferably 3.5 to 4.5 (ηrel: 97% sulfuric acid 100 m at 30 ° C.).
Nylon 4 with ηa measured on a solution of 1 g of polymer in l
It is advantageous to use 6.

When coloring the nylon 46 according to the present invention, it is necessary to select the ratio (ηa / ηc) of the relative viscosity ηc of the base material to the relative viscosity ηa of the nylon 46 to be 1.05 to 1.25. If it is out of this range, an excellent colored molded article cannot be obtained.

The color concentrate composition and the nylon 46 resin to be colored are usually mixed in the same manner as each natural pellet. The mixing ratio of the two is the color concentrate composition 1
Nylon 4,6 with respect to parts by weight, preferably 10 to 100 parts by weight, more preferably 15 to 70 parts by weight, particularly preferably 20 to
It is preferable to mix in the range of 50 parts by weight, and when this is molded by an injection molding machine, a good colored molded product without color unevenness or dispersion failure can be obtained.

In the present invention, additives such as a flame retardant, an ultraviolet absorber and an antistatic agent may be added in advance and kneaded during the production of the color concentrate composition.

d. Examples In the examples,% and parts are% by weight and parts by weight, respectively.

Examples 1 and 3 The following color concentrate components were blended in a Henschel type mixer and then extruded at an extrusion temperature of 230 using an extruder.
Pellets of the color concentrate composition were prepared at ° C.

Color Concentrate Composition A: Nylon 6 with Relative Viscosity 2.9 / Carbon Black / Bengala (iron oxide) / Ethylenebisstearic acid amide = 72 / 2.2
/16.5/9.3 (wt%) Color Concentrate Composition B: Nylon 6 / Carbon Black / Bengala / Ethylenebisstearic acid amide = 68 / 3.8 / 19.7 / 8.5 with relative viscosity 3.1
(weight%).

In Example 1, a ratio of nylon 46 / color concentrate composition A = 40/1 (parts by weight) having a relative viscosity of 3.5 was used, and in Example 3, a nylon 46 / color concentrate composition having a relative viscosity of 3,8 was used. The respective components were mixed in a tumbler so that the ratio of B = 40/1 (parts by weight) was obtained, and then the mixture was molded by an injection molding machine to obtain a colored molded product. Physical properties of the obtained test piece were evaluated by the following evaluation methods, and the results shown in Table 1 were obtained.

(Evaluation method) Izod impact strength: ASTM D256 23 ℃ Notched Bending strength, flexural modulus: ASTM D790 Bending speed 15mm / mi
n Tensile strength, tensile elongation: ASTM D638 Tensile speed 50mm / min Rockwell hardness: ASTM D785 R scale Deflection temperature under load: ASTM D648 Load 18.6kg / cm ² No annealing Molding appearance: Thickness 1.6mm Alignment plate Color unevenness: Colored molding Non-uniformity of pigment in product Dispersibility: Aggregation of pigment in colored molded product Judgment: ◎ (good)-○-△ -x- (poor) Example 2 Titanium oxide on 60% nylon 66 resin with relative viscosity 3.3 : 9.6
%), Titanium Yellow 16.4%, Carbon Black 0.
After blending 8%, red iron oxide (iron oxide) 6.8% and ethylenebisstearic acid amide 6.4% with a Henschel type mixer, pellets of Color Concentrate Composition C were produced at an extrusion temperature of 270 ° C. using an extruder.

1 part by weight of the obtained color concentrate composition was set to a mixing weight ratio of 40 parts by weight of nylon 46 resin natural pellets having a relative viscosity of 3,5 and mixed by a tumbler, followed by molding by an injection molding machine, A colored molded product was obtained.

From the results shown in Table-1, it was found that the molded article of the present invention had the physical properties and the molded appearance targeted by the present invention.

Comparative Examples 1-3 Comparative Examples 1 and 2 use the same nylon 46 resin natural pellets having a relative viscosity of 3,0 as the color concentrate composition prepared in Example 2 and have the same mixing ratio as in Example 2. After setting in this way and mixing with a tumbler, a colored molded product was obtained by molding with an injection molding machine. The results are shown in Table-1.

Comparative Examples 1 and 2 are molded products having a relative viscosity relationship ηa / ηc outside the range of the present invention, and the molded appearance is not preferable.

In Comparative Example 3, 57.0% of nylon 66 resin having a relative viscosity of 3.5 was blended with 12.7% of carbon black, 20.1% of red iron oxide, and 9.2% of ethylenebisstearic acid amide in a Henschel type mixer, and then an extruder was used at an extrusion temperature of 270. Pellets of Color Concentrate Composition D were prepared at ° C. 1 part by weight of the obtained color concentrate composition was mixed with a tumbler with a mixing weight ratio of 30 parts by weight of nylon 46 resin natural pellets having a relative viscosity of 3,0 and mixed by a tumbler, followed by molding with an injection molding machine. A colored molded product was obtained.

Physical properties of the obtained test piece were evaluated by the same evaluation methods as in Example-1, and the results shown in Table 1 were obtained.

From the results shown in Table-1, the molded product was inferior in appearance and the desired physical properties were not obtained.

Comparative Example-4 Carbon black 1 to 60% nylon 46 resin with relative viscosity 3.5
After blending 1.5%, red iron oxide 22.0%, ethylenebisstearic acid amide 6.5% with a Henschel mixer,
Pellets of Color Concentrate Composition E were produced using an extruder at an extrusion temperature of 300 ° C. Color mixing is performed by mixing the tumbler in a mixing weight ratio of 30 parts by weight of nylon 46 resin pellets having a relative viscosity of 3,0 to 1 part by weight of the obtained color concentrate composition, followed by molding with an injection molding machine. I got the goods.

Each physical property of the obtained test piece was evaluated by the same evaluation method as in Example-1, and the results shown in Table 1 were obtained.

From the results in Table 1, the relative viscosity relationship ηa / ηc is a composition outside the range of the present invention, and the physical properties of rigidity, impact resistance, heat resistance and molding appearance are unbalanced, which is not preferable.

Comparative Example 5 Nylon 6 / Carbon Black / Bengala / Ethylenebisstearic acid amide with relative viscosity of 2.2 = 68 / 3.8 / 19.7 / 8.5
(Wt%) was kneaded in the same manner as in Example 1 to obtain a color concentrate composition F. Next, in the same manner as in Example 1, nylon 46 / color outlet composition F = 40/1 (weight ratio) was mixed and molded to obtain a colored molded product. Table 1 shows the results of measuring the physical properties of the obtained molded product. The strength and elongation are inferior to those of Example 1.

e. Effect of the Invention The method for coloring a polyamide resin of the present invention is to mix a nylon 46 resin with a base material made of a polyamide resin and a color concentrate composition obtained by uniformly dispersing a colorant and a coloring dispersion aid therein. In the method for coloring a nylon 46 resin, a base material having a relative viscosity of 2.5 to 4.5 is used, and the relationship between the relative viscosity ηc of the color concentrate composition and the relative viscosity ηa of the nylon 46 resin [ηa / η
By mixing c] under the condition of more than 1.0, a resin composition having a balance of rigidity, impact resistance, heat resistance and physical properties of molding appearance can be obtained.

Therefore, since the colored polyamide resin product of the present invention has an excellent balance of physical properties, it is possible to provide molded products such as automobile interior / exterior parts and various parts in the electric / electronic field which require particularly severe molding appearance. The industrial utility value is extremely high.

Continuation of front page (56) Reference JP-A-61-188462 (JP, A) JP-A-56-47435 (JP, A)

Claims (2)

[Claims] 1. A method for coloring a color concentrate composition comprising a polyamide resin as a base material, which is uniformly mixed with a colorant, and mixing the color concentrate composition with a polytetramethylene adipamide resin, the method comprising: Relative viscosity of base material (97% sulfuric acid
A solution of 1 g of polymer in 100 ml is measured at 30 ° C.) ηc is 2.5-
4.5, and the relative viscosity (measured under the same conditions as the base material) ηa of the polytetramethylene adipamide resin is such that the ratio of the two is ηa / ηc = 1.05 to 1.25. Coloring method. 2. The method for coloring a polyamide resin according to claim 1, wherein the base material is a polycaprolactam resin and / or a polyhexamethylene adipamide resin.