GB2165850A

GB2165850A - Precolored polyamide molding composition

Info

Publication number: GB2165850A
Application number: GB08519950A
Authority: GB
Inventors: Shuji Ogawa; Fumio Kondo; Toshikazu Mori
Original assignee: Dainichiseika Color and Chemicals Mfg Co Ltd
Current assignee: Dainichiseika Color and Chemicals Mfg Co Ltd
Priority date: 1984-08-24
Filing date: 1985-08-08
Publication date: 1986-04-23
Also published as: GB8519950D0; DE3529788C2; JPS6155146A; DE3529788A1; GB2165850B

Abstract

Precolored polyamide molding composition contains a polyamide resin, a dye or a pigment, and additionally a compound represented by the following general formula: <IMAGE> wherein R is an alkylene group of one to four carbon atoms, and R' and R'' are fatty acid residues of nine to eighteen carbon atoms. The molded parts prepared from this composition show excellent tensile elongation and impact strength.

Description

SPECIFICATION Precoloured polyamide molding composition Background of the invention Field of the invention This invention relates to a precoloured polyamide molding composition and is particularly concerned with a precoloured polyamide molding composition suitable for getting precoloured parts of excellent impact strength and tensil elongation.

Prior arts Many kinds of colorants involving dyes and pigments have been conventionally employed in order to impart aesthetic feeling to polyamide resin molding parts and to improve their weathering characteristics.

Among others, such a colorant as carbon black has been used more frequently. When carbon black or a similar pigment is blended to the polyamide resin, some of its properties such as weathering characteristics are improved. Its impact strength tensil elongation and the like, however, are decreased rapidly compared with those of uncoloured natural resin.

Combination of carbon black and nigrosine was proposed to solve the problem described above ( see, for example, Japanese Laid-open Patent publication No.115,454/1982). Nigrosin exerted its effect to nylon 6, but there was little contribution to nylon 66. Further, it was impossible to combine nigrosine with dyes and pigments other than black ones to precolour molding material.

Summary ofthe invention Accordingly, it is an object of this invention to provide a precoloured polyamide molding composition suitable for getting aesthetic molded parts.

Another object of this invention is to improve such properties of the molded parts as impact strength, tensil elongation and the like.

These and further objects and advantages of this invention will become more apparent and be fully understood from the hereinafter detailed description.

Detailed description It has been found that when a polyamide resin is blended with carbo black or other dyes and pigments to precolor and mold the resin, a combination of such colorants and an alkylene bis(fatty amide) contributes to its improved properties such as impact strength, tensil elengation and the like.

According to this invention, it is provided a precoloured polyamide molding composition containing a polyamide resin and a dye or a pigment which comprises further including therein a compound represented by the following general formula:

wherein R is an alkylene group of one to four carbon atoms, and R' and R" are fatty acid residues of nine to eighteen carbon atoms.

Polyamide resins which can be used in this invention include, for example, polycaprolactam (nylon 6), polylaurolactam (nylon 12), poly (11 -aminoundecanoic acid) (nylon 11), polyhexamethylene adipamide (nylon 66), polyhexamethylene azelamide (nylon 69), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecanamide (nylon 612), poly [bis (4-aminocyclohexyl)methane dodecanamide ] and the like. Among others nylon 6 and nylon 66 are particularly useful polyamide resins of this invention.

Dyes and pigments used in this invention to precolorthe polyamide resins described above include azo-, anthraquinone-, quinophthalone-, quinacridone-, perylene-, perynone-, isoindolinone-, dioxazine-, phthalocyanine dyes and pigments, iron oxide-, titanium oxide-, ultramarine-, cadmium pigments, cobalt blue, carbon black and the like. These colorants are blended in the range from 1 to 60% by weight of the polyamide resin, when the precolored molding composition is employed as a master batch. And when the precolored molded parts of polyamide resin are prepared, such master bach is diluted by natural resins, or dyes and pigments are added directly to the resins until the final concentration of colorants falls in the range from 0.005 to 5.0% by weight. When carbon black is used as the colorant, it is preferable to have a particle diameter of 8 to 120 my.

When the polyamide resin is blended with dyes and pigments described above, such colorants are combined with a compound of general formula:

wherein R is an alkylene group of one to four carbon atoms, and R' and R" are fatty acid residues of nine to eighteen carbon atoms. The compound represented by the general formula (1 ) includes, for example, methylene-bis(stearamide), ethylene-bis(stearamide), methylene-bis (lauramide), ethylene-bis(lauramide), methylene-bis(myristamide), ethylene-bis(myristamide), methylene-bis(palmitamide), ethylene-bis (palmitamide), methylene-bis(oleicamide), ethylene-bis(oleicamide), methylene-bis(linolamide), ethylenebis(linolamide), and the like. Among others, ethylene-bis(stearamide) or methylene-bis(stearamide) is particularly preferable.

The compound represented by the general formula (1) is preferably added to polyamide in the range of 0.2% by weight of the resin when the composition obtained is used as a master batch, final concentration thereof in the precolored moled parts being 0.001 to 3.0% by weight.

The precoloured polyamide molding composition of this invention can be prepared by conventional procedures. It is prepared, for example, by adding dyes or pigments and the compound (1) into melt polyamide resin and kneading the mixture thus obtained by means of a kneader such as extruders or Bambury mixer. Commercially, it is preferable to produce the precolored molded parts by melt-extruding the composition through an extruder and pelleting the extrudate by a pelletizer to form master pellets, which are then dilluted by a natural resin.

Since the compound (1) is employed along with a dye or a pigment in the precolored polyamide molding composition of this invention, existing problems such as a decrease in impact strength, tensil elongation and the like due to the addition of the colorant have been solved.

The precolored polyamide molding composition of this invention will be more fully described in the following. They serve to give specific illustrations of the practice of this invention, but are not intended in any way to limit the scope of this invention. The percentage of each colorant and the compound (1) both in the master batch and the moulded parts is based on the weight.

Examples and comparative examples Master pellets of precolored polyamide molding compositions were prepared by adding a variety of dyes and pigments listed in Table 1 below along with the compound of the general formula (1 ) into a polyamide resin (nylon 6 and nylon 66) and melt-extruding the mixture. These master pellets were dilluted with those of natural resin and injection-molded. Tensil elongation and impact strength of molded parts thus prepared were determined. The results obtained are shown in Table 1.

TABLE 1 Master batch Molded parts Nos of Final concenbation Properties Examples and Polyamide Colorand partcle Compound (1)/ Colorant Compound(1) Tensil elon- Impact strength Comparative dlameter(m ); Amountused(%) (%) (%) gation(%) (kglcm2) Examples Amountused(%) nylon 66 carbon black ethylene-bis Ex.1 25m ; 20% (stearamide)/5.0% 2.0 0.5 49 840 nylon 66 carbon black methylene-bis Ex.2 25m ; 20% (stearamide)/4.0% 2.0 0.4 38 832 nylon 66 carbon black ethylene-bis Ex.3 25m ; 10% (stearamide)/3.0% 0.3 0.09 115 806 nylon 6 carbon black ethylene-bis Ex.4 16m ; 10% (stearamide)/3.0% 0.03 0.009 80 798 nylon 6 carbon black ethylene-bis Ex.5 16m ; 10% (stearamide)/3.0% 0.3 0.09 104 770 nylon 6 iron oxide ethylene-bis Ex.6 yellow 4.0% (stearamide)/1.0% 0.2 0.05 70 796 nylon 6 iron oxide red ethylene-bis Ex.7 10.0% (stearamide)/2.0% 0.5 0.10 120 780 nylon 6 cyanine green ethylene-bis Ex.8 2.0% (stearamide)/0.6% 0.1 0.03 82 821 nylon 6 cyanine blue ethylene-bis Ex.9 6.0% (stearamide)/2.0% 0.3 0.10 108 792 nylon 6 ultramarine ethylene-bis Ex.10 20.0% (stearamide)/2.0% 1.0 0.10 95 760 TABLE 1(continued) Master batch Molded parts Final concenbation Properties Nos 1 Examples and Polyamide Colorand partcle Compound (1)/ Colorant Compound(1) Tensil elon- Impact strength Comparative dlameter(m ); Amountused(%) (%) (%) gation(%) (kglcm2) Examples Amountused(%) nylon 66 Comp. Ex.1 (natural) - - - - 200% < 766 nylon 66 carbon black Comp. Ex.2 28m ; 20% - 2.0 - 9 808 nylon 66 carbon black Comp.Ex.3 22m ; 20% - 2.0 - 10 835 nylon 66 carbon black Comp. Ex.4 25m ; 20% - 2.0 - 8 747 nylon 66 carbon black (aniline black) (aniline) Comp. Ex.5 25m ; 20% 4.0% 2.0 black 0.4) 10 775 nylon 66 carbon black Comp. Ex.6 25m ; 10% - 0.3 - 70 758 nylon 6 Comp. Ex.7 (natural) - - - - 90 800 nylon 6 carbon black Comp. Ex.8 16m ; 10% - 0.03 - 49 795 nylon 6 carbon black Comp. Ex.9 16m ; 10% - 0.3 - 27 802 nylon 6 carbon black (aniline black) (aniline Comp. Ex.10 16m ; 10% 3.0% 0.3 black 0.09) 85 785 TABLE 1 (continued) Master batch Molded parts Nos of Final concenbation Properties Examples and Comerstive Polyamide Colorand partcle Compound (1)/ Colorant Compound(1) Tensil elon- Impact strength Examples diameter(m ); Amountused(%) (%) (%) gation(%) (kglcm2) Amountused(%) Comp. Ex.11 nylon 6 iron oxide yellow 4.0% - 0.2 - 50 798 Comp. Ex.12 nylon 6 rion oxide red 10.0% - 0.5 - 44 794 Comp. Ex.13 nylon 6 cyanine green 2.0% - 0.1 - 41 824 Comp. Ex.14 nylon 6 cyanine blue 6.0% - 0.3 - 27 796 comp. Ex.15 nylon 6 marine blue 20.0% - 1.0 - 40 765

Claims

1. Precolored polyamide molding composition containing a polyamide resin and a dye or a pigment which comprises further including therein a compound represented by the following general formula:

wherein R is an alkylene group of one to four carbon atoms, and R' and R" are fatty acid residues of nine to eighteen carbon atoms

2. A composition claimed in claim 1 wherein the pigment is carbon black having a particle diameter of 8 to 120 m .

3. A composition claimed in claim 1 wherein the compound of general formula (1) is ethylenebis(stearamide).

4. A composition claimed in claim 1 wherein the compound of general formula (1) is methylenebis(stearamide).

5. A composition claimed in cliam 1 wherein the polyamide resin is nylon 66.

6. A composition claimed in claim 1 wherein the polyamide resin is nylon 6.