JPH11228813A - Polyamide resin composition for laser marking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyamide resin composition for laser marking adapted to produce a resin molded product capable of allowing a sharp printing or image to be applied on the surface of the product by a laser beam, excellent in mechanical properties and good in exteriority and flame-retardant property. SOLUTION: This composition is obtained by blending (C) 30 to 150 pts.wt. of an inorganic filler, (D) 0.5 to 10 pts.wt. of red phosphorus, (E) 0 to 80 pts.wt. of a flame-retardant agent other than red phosphorus and (F) 0.01 to 10 pts.wt. of a coloring agent comprising a carbon black and/or titanium black with 100 pts.wt. of a polyamide resin mixture comprising (A) 20 to 90 wt.% of a polyamide resin and (B) 10 to 80 wt.% of an aromatic polyamide resin, wherein the aromatic polyamide resin comprises, as a main component, a polyamide obtained from a condensation polymerization reaction between an aliphatic dicarboxylic acid and a diamine mixture comprising a p-xylylenediamine and m- xylylenediamine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition for laser marking, and more particularly, it is suitable for applying clear printing and drawing on the surface of a molded article using a laser beam.
The present invention relates to a flame-retardant polyamide resin composition for laser marking which has excellent flame retardancy.

[0002]

2. Description of the Related Art There have already been proposed many methods for marking a thermoplastic resin by irradiating a laser beam, for example, (1) a method of adding carbon black and / or graphite to a thermoplastic resin. Is Japanese
Japanese Patent Application Laid-Open No. Sho 58-116620 discloses a method for etching a mark layer on a resin surface with a laser beam.
Japanese Patent Application Laid-Open No. 63-216790 discloses a method of adding a filler which discolors or decolors by laser light.

Further, as a polyamide resin having excellent laser marking properties, a polyamide resin composition obtained by blending carbon with a polyamide having a controlled moisture content is disclosed in JP-A-8-85.
No. 757. However, polyamide resin has high water absorption, it is not easy to control the moisture content, and it is difficult to perform stable molding due to foaming and drawing, and a relatively large amount of flame retardant is required to make it flame-retardant It causes deterioration of mechanical properties.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide clear printing and drawing on the surface of a resin molded product by laser light, excellent mechanical properties, and appearance characteristics and flame retardancy of the molded product. It is to provide a polyamide resin composition for laser marking excellent in the above.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the present invention is as follows.
100 to 100 parts by weight of a mixed polyamide resin comprising 20 to 90% by weight of a polyamide 6 resin and 10 to 80% by weight of an aromatic polyamide resin (B), 30 to 150 parts by weight of an inorganic filler (C), 0.5 to 10 parts by weight, (E) 0 to 80 parts by weight of a flame retardant other than red phosphorus, and (F) a coloring agent containing carbon black and / or titanium black 0.01 to
10 parts by weight, wherein the aromatic polyamide resin is a polyamide resin having a polyamide as a main component obtained by a polycondensation reaction of a mixed diamine containing paraxylylenediamine and metaxylylenediamine with an aliphatic dicarboxylic acid. Which is a polyamide resin composition for laser marking.

Hereinafter, the present invention will be described in detail. The (A) polyamide 6 resin in the present invention is a polyamide having a caprolactam unit of 90 mol% or more,
It may contain a unit composed of a comonomer component other than the caprolactam unit. Examples of the unit composed of a comonomer component other than the caprolactam unit include ω-laurolactam.

The relative viscosity of the polyamide 6 resin is preferably 1.8 to 4.0 as measured at a concentration of 1 g / 100 ml in 98% sulfuric acid at a temperature of 25 ° C. If the relative viscosity is too low, the mechanical strength is insufficient, and if it is too high, the moldability decreases. The relative viscosity of the polyamide 6 resin is more preferably from 2.0 to 3.8, and most preferably from 2.1 to 3.6.
It is.

As the aromatic polyamide resin (B) in the present invention, a polyamide resin mainly composed of a polyamide obtained by a polycondensation reaction of a mixed diamine containing paraxylylenediamine and metaxylylenediamine with an aliphatic dicarboxylic acid is used. It is.

[0009] The mixed diamine is preferably a mixed diamine containing 15 to 50 mol% of paraxylylenediamine and 50 to 85 mol% of metaxylylenediamine. When the proportion of para-xylylenediamine in the mixed diamine is less than 15 mol%, the crystallization rate of the obtained polyamide is low, and deformation and mechanical strength are likely to be reduced due to deterioration in moldability or poor crystallization of the molded product, If it exceeds 50 mol%, the melting point of the obtained polyamide resin will be too high, which will easily cause thermal deterioration due to heating during molding, making molding difficult. More preferably, the mixed diamine is a mixed diamine comprising 15 to 50 mol% of paraxylylenediamine and 50 to 85 mol% of metaxylylenediamine.

The diamine in the mixed diamine containing paraxylylenediamine and metaxylylenediamine includes, in addition to paraxylylenediamine and metaxylylenediamine, aliphatic diamines, aromatic diamines and alicyclic diamines. The ratio of the diamine other than para-xylylenediamine and meta-xylylenediamine in the mixed diamine is preferably 10 mol% or less of the total diamine, and more preferably 5 mol% or less of the total diamine.

Examples of the aliphatic diamine include tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, octamethylene diamine, nonamethylene diamine, and the like, and examples of the aromatic diamine include metaphenylenediamine and paraphenylenediamine. Examples of the alicyclic diamine include 1,3-
Bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane and the like can be mentioned.

As the aliphatic dicarboxylic acid, preferably, an α, ω-aliphatic dicarboxylic acid is used. The aliphatic dicarboxylic acid preferably has 6 to 12 carbon atoms. Specific examples of the aliphatic dicarboxylic acid include adipic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid and the like.

In the aromatic polyamide resin, a small amount of aromatic dicarboxylic acid can be used in addition to the aliphatic dicarboxylic acid. Examples of the aromatic dicarboxylic acid include 1,5-naphthalenedicarboxylic acid and the like. The proportion of the aromatic dicarboxylic acid is preferably 10 mol% or less, more preferably 5 mol% or less of the total dicarboxylic acid.

The relative viscosity of the aromatic polyamide resin is 96
It is preferably 1.5 to 4.0 when measured at a concentration of 1 g / 100 ml in 25% sulfuric acid at a temperature of 25 ° C. If the relative viscosity is too low, the mechanical strength is insufficient, and if it is too high, the moldability decreases. The relative viscosity of the aromatic polyamide resin is more preferably 1.6 to 3.9, and most preferably 1.7.
３3.8.

The mixed polyamide resin in the present invention comprises (A) polyamide 6 resin and (B) aromatic polyamide resin, and the ratio of (A) polyamide 6 resin to (B) aromatic polyamide resin is 20 to 90% by weight / 10
80% by weight. If the content of the polyamide 6 resin is less than 20% by weight, it is difficult to obtain a product having a good appearance.
If it exceeds 0% by weight, it is difficult to obtain a sufficient elastic modulus. The ratio of (A) polyamide 6 resin to (B) aromatic polyamide resin is preferably 25 to 80% by weight / 20 to 80% by weight.
75% by weight.

The inorganic filler (C) in the present invention includes fibrous, powdery, granular and flake-like inorganic fillers and a combination thereof. Examples of the fibrous filler include glass fibers, whiskers of potassium titanate and calcium sulfate, carbon fibers, and alumina fibers. The average fiber length of the fibrous filler is preferably 500 μm or less in the molded article, more preferably 200 μm or less in the molded article. The average fiber length is measured by a microscope.

Examples of the powdery, granular or flake inorganic filler include kaolinite, silica, mica, glass flake, glass beads, carbonates such as calcium carbonate and magnesium carbonate, sulfates such as calcium sulfate and magnesium sulfate, Examples include sulfides and metal oxides. Further, it is preferable to mix talc powder in order to promote crystallization of the polyamide resin. The average particle size of the powdery, granular or flake inorganic filler is preferably 10
It is 0 μm or less, and more preferably 50 μm or less. In the resin composition of the present invention, it is preferable to use a fibrous filler and a powdery, granular or flake-like inorganic filler in combination from the viewpoint of reinforcing effect and dimensional stability.

The compounding amount of the inorganic filler is 100% by weight of a mixed polyamide resin comprising (A) 20 to 90% by weight of a polyamide 6 resin and (B) 10 to 80% by weight of an aromatic polyamide resin.
The amount is 30 to 150 parts by weight, preferably 40 to 130 parts by weight based on parts by weight. If the amount of the inorganic filler is too small, the elastic modulus is insufficient, and if it is too large, it becomes difficult to obtain a product having a good appearance.

The (D) red phosphorus in the present invention is usually a dark red powder having a specific gravity of about 2.1 to 2.3,
It is obtained by converting yellow phosphorus into red phosphorus by heating in a conversion kettle and purifying the same. The compounding amount of red phosphorus is 0.5 to 10 parts by weight based on 100 parts by weight of a mixed polyamide resin comprising (A) 20 to 90% by weight of a polyamide 6 resin and (B) 10 to 80% by weight of an aromatic polyamide resin. It is. If the amount of red phosphorus is less than 0.5 part by weight, it is difficult to obtain a sufficient flame retardant effect and clear printing and drawing by laser marking, and if it exceeds 10 parts by weight, a good molded article appearance is obtained. Becomes difficult. The compounding amount of red phosphorus is preferably 1 to 8 parts by weight based on 100 parts by weight of a mixed polyamide resin composed of (A) 20 to 90% by weight of a polyamide 6 resin and (B) 10 to 80% by weight of an aromatic polyamide resin. It is.

As the flame retardant other than (E) red phosphorus in the present invention, any flame retardant which is generally commercially available can be used, and preferred examples include a halogen-based flame retardant and a phosphorus-based flame retardant. Preferred examples of the halogen-based flame retardant include halogenated polymers. Specific examples of the halogenated polymer include halogenated polystyrene, halogenated epoxy, halogenated polycarbonate, and halogenated polyphenylene ether.

When a halogen-based flame retardant is blended, it is preferable to further use an inorganic flame retardant. Examples of the inorganic flame retardant include antimony trioxide, antimony tetroxide, antimony pentoxide, zinc hydroxystannate, zinc borate, aluminum hydroxide and magnesium hydroxide. Examples of the phosphorus-based flame retardants include phosphate esters, ammonium phosphate salts, ammonium polyphosphate, halogen phosphate esters, melamine phosphate, melam phosphate, and mixtures thereof.

The amount of the flame retardant other than red phosphorus is based on 100 parts by weight of a mixed polyamide resin comprising (A) 20 to 90% by weight of a polyamide 6 resin and (B) 10 to 80% by weight of an aromatic polyamide resin. 10 to 80 parts by weight. If the amount of the flame retardant other than red phosphorus is less than 10 parts by weight, the flame retardant effect is insufficient, and if it exceeds 80 parts by weight, the appearance of the molded article is deteriorated. The compounding amount of the flame retardant other than red phosphorus is a mixed polyamide resin 10 comprising (A) 20 to 90% by weight of a polyamide 6 resin and (B) 10 to 80% by weight of an aromatic polyamide resin.
It is preferably 15 to 70 parts by weight with respect to 0 parts by weight.

Examples of the colorant other than carbon black and titanium black in the colorant (F) containing carbon black and / or titanium black in the present invention include, for example, zinc sulfide, titanium oxide, nickel antimony titanium yellow, and chromium antimony titanium rutile. And copper phthalocyanine blue.

The amount of the colorant containing carbon black and / or titanium black is as follows: (A) 20 to 90% by weight of polyamide 6 resin and (B) aromatic polyamide resin 10
The amount is 0.01 to 10 parts by weight based on 100 parts by weight of the mixed polyamide resin consisting of 〜80% by weight. If the amount of the coloring agent containing carbon black and / or titanium black is less than 0.001 part by weight, a sufficient coloring effect cannot be obtained, and it is difficult to obtain clear printing and drawing by laser marking. Exceeding the part lowers the extrusion workability, making it difficult to obtain a good molded product appearance and mechanical properties. The compounding amount of the coloring agent containing carbon black and / or titanium black is as follows: (A) polyamide 6
20 to 90% by weight of resin and (B) aromatic polyamide resin 1
It is preferably 0.05 to 8 parts by weight based on 100 parts by weight of the mixed polyamide resin consisting of 0 to 80% by weight.

In the polyamide resin composition for laser marking of the present invention, if necessary, other additives such as an antistatic agent, a lubricant, a plasticizer, a stabilizer against deterioration by oxidation, heat and ultraviolet rays, etc. may be blended. can do. In order to produce the polyamide resin composition for laser marking of the present invention, a known compounding method can be used. Method. In order to manufacture a molded article from the polyamide resin composition for laser marking of the present invention, a known molding method can be used, and examples of the molding method include an injection molding method.
A molded article obtained by molding the resin composition of the present invention has excellent surface appearance at a general mold temperature (70 to 90 ° C.).

In order to perform laser marking on a molded article made of the polyamide resin composition for laser marking of the present invention, for example, a pulsed laser capable of giving an energy of 0.5 J / cm ² pulse or more to an irradiation surface, Alternatively, by using a scanning laser having an output of 0.5 W or more, clear laser marking can be provided. Such lasers include carbon dioxide laser, semiconductor laser, YAG
A laser, an excimer laser, and the like can be given, and a TAE-type carbon dioxide laser, a scanning carbon dioxide laser, a YAG laser, and the like are preferable.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

EXAMPLES The following components were used in Examples and Comparative Examples. (1) Polyamide 6 resin: Novamid 1008 manufactured by Mitsubishi Engineering-Plastics Corporation, relative viscosity
3. (2) Aromatic polyamide resin: The aromatic polyamide A obtained in Reference Example 1. (3) Aromatic polyamide resin: The aromatic polyamide B obtained in Reference Example 2.

(4) Inorganic filler: talc, Hayashi Kasei Co., Ltd.
Micron White 5000A, average particle size 4.1 μm. (5) Inorganic filler: glass fiber, ECS03T-296GH manufactured by NEC Corporation, average fiber diameter 10 μm, average fiber length 150 μm. (6) Inorganic filler: calcium carbonate, NS100 manufactured by Nitto Powder Chemical Co., Ltd., particle size 1.5 μm.

(7) Red phosphorus: Red phosphorus, Nippon Chemical Industry Co., Ltd. Hishigard TP-10. (8) Flame retardant: Brominated polystyrene, GREAT LAKES manufactured by Great Lakes Chemical Corporation
PDBS-80. (9) Flame retardant auxiliary agent: Antimony trioxide, PATOX-M manufactured by Nippon Seiko Co., Ltd. (10) Colorant: carbon black, carbon black # 44B manufactured by Mitsubishi Chemical Corporation.

Reference Example 1 Adipic acid was heated and melted in a reaction vessel in a nitrogen atmosphere. A mixed xylylenediamine containing 30 mol% of paraxylylenediamine and 70 mol% of metaxylylenediamine was added dropwise to the molten dicarboxylic acid, followed by stirring while maintaining the reaction temperature so as to always exceed the melting point of the product. . After completion of the dropwise addition, stirring and reaction were continued until the viscosity reached a predetermined value. At that time, the product was discharged from the reactor, cooled with water, and pelletized. The obtained aromatic polyamide A has a melting point of 258 ° C., a crystallization temperature of 206 ° C., and a relative viscosity of 2.08 (96% sulfuric acid solution 1 g / 100 ml).
Met.

Reference Example 2 Adipic acid was heated and melted in a reaction vessel in a nitrogen atmosphere. In the molten dicarboxylic acid, a mixed xylylenediamine containing 50 mol% of paraxylylenediamine and 50 mol% of metaxylylenediamine and metaxylylenediamine were finally mixed with 40 mol% of paraxylylenediamine and metaxylylenediamine. Amine 60 mol%
Then, the mixture was added dropwise in two stages, and stirred while maintaining the reaction temperature so as to always exceed the melting point of the product. After completion of the dropwise addition, stirring and reaction were continued until the viscosity reached a predetermined value. At that time, the product was discharged from the reactor, cooled with water, and pelletized. The obtained polyamide B has a melting point of 269 ° C., a crystallization temperature of 227 ° C., and a relative viscosity of 1 g / 1 (96% sulfuric acid solution).
00ml) was 2.13.

(11) Molding conditions: cylinder temperature 280
° C, mold temperature 90 ° C, injection pressure 1000 kg / cm ² . (12) Bending test: ASTM-D790 (13) Flame retardancy test: Based on UL94 test method. (14) Laser marking test: NEC marker engine SL475H (YAG laser, oscillation wavelength 1.06
(μm, pulse frequency ５０50 kHz), and scanned with laser light, drawn a circle having a diameter of 5 mm, and visually checked the contrast. The evaluation was evaluated as ◎ when the contrast was very clear, ○ when the contrast was clear, Δ when the contrast was unclear, and × when the contrast was not visible.

Example 1 2 parts by weight of talc, 40 parts by weight of glass fiber, and 90 parts by weight of calcium carbonate were added to 70 parts by weight of a polyamide 6 resin and 30 parts by weight of an aromatic polyamide A for a total of 100 parts by weight. Parts, 40 parts by weight of brominated polystyrene, 20 parts by weight of antimony trioxide, and 3 parts by weight of red phosphorus, and using a vented single screw extruder (manufactured by Nakatani Machine Co., Ltd.) at a cylinder temperature of 280 ° C. After melt-kneading, the mixture was cooled with water and pelletized. Using the pellets of the obtained resin composition, a test piece for bending test, a strip test piece of 1.6 mm in thickness for UL test, and a 100 mm disk test piece for laser marking were formed by an injection molding machine. Table 1 shows the evaluation results.

Example 2 Pellets were obtained and test pieces were formed in the same manner as in Example 1, except that the polyamide 6 resin was changed to 60 parts by weight and the aromatic polyamide A was changed to 40 parts by weight. . Table 1 shows the evaluation results. [Example 3] In Example 1, the polyamide 6 resin was replaced with 3
Pellets were obtained and test pieces were formed in the same manner as in Example 1 except that 0 parts by weight and the aromatic polyamide A were 70 parts by weight. Table 1 shows the evaluation results.

Example 4 A pellet was obtained and a test piece was formed in the same manner as in Example 1 except that aromatic polyamide A was changed to aromatic polyamide B. Table 1 shows the evaluation results. [Example 5] Pellets were obtained in the same manner as in Example 1, except that 10 parts by weight of red phosphorus was blended without blending brominated polystyrene and antimony trioxide.
Test pieces were molded. Table 1 shows the evaluation results.

Comparative Example 1 A pellet was prepared in the same manner as in Example 1 except that 100 parts by weight of the polyamide 6 resin was used instead of 70 parts by weight of the polyamide 6 resin and 30 parts by weight of the aromatic polyamide A. And a test piece was molded. Table 1 shows the evaluation results. [Comparative Example 2] In Example 1, the polyamide 6 resin 70 was used.
A pellet was obtained and a test piece was formed in the same manner as in Example 1, except that 100 parts by weight of the aromatic polyamide A was used instead of using 30 parts by weight of the aromatic polyamide A and 30 parts by weight of the aromatic polyamide A. Table 1 shows the evaluation results. [Comparative Example 3] A pellet was obtained and a test piece was formed in the same manner as in Example 1 except that red phosphorus was not added. Table 1 shows the evaluation results.

[0037]

[Table 1]

[0038]

EFFECT OF THE INVENTION The polyamide resin composition for laser marking of the present invention is capable of sharply applying light-colored printing and drawing on the surface of a molded product, particularly on the surface of a black or dark-colored molded product, by laser light, and has excellent strength, It has an elastic modulus and moldability, and is excellent in surface appearance and flame retardancy at a relatively low mold temperature, and is very useful as automobile parts, electric and electronic parts, and various industrial parts.

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Claims (7)

[Claims] 1. 100 parts by weight of a mixed polyamide resin comprising (A) 20 to 90% by weight of a polyamide 6 resin and (B) 10 to 80% by weight of an aromatic polyamide resin, and (C) 30 to 150 parts by weight of an inorganic filler. Parts, (D) 0.5 to 10 parts by weight of red phosphorus, (E) 0 to 80 parts by weight of a flame retardant other than red phosphorus, and (F) 0.01 to 10 parts by weight of a coloring agent containing carbon black and / or titanium black. The aromatic polyamide resin is a polyamide resin having a polyamide as a main component obtained by a polycondensation reaction between a mixed diamine containing paraxylylenediamine and metaxylylenediamine and an aliphatic dicarboxylic acid. Polyamide resin composition for laser marking. 2. The polyamide 6 resin has a relative viscosity of 1.8.
2. The polyamide resin composition for laser marking according to claim 1, wherein the number is from 4.0 to 4.0. 3. 3. A mixed diamine comprising 15 to 50 mol% of paraxylylenediamine and 50 to 8 metaxylylenediamine.
The polyamide resin composition for laser marking according to claim 1 or 2, which is a mixed diamine containing 5 mol%. 4. The polyamide resin composition for laser marking according to claim 1, wherein the aliphatic dicarboxylic acid is an α, ω-linear aliphatic dicarboxylic acid. 5. An aliphatic dicarboxylic acid having 6 to 12 carbon atoms.
2. An aliphatic dicarboxylic acid according to claim 1,
5. The polyamide resin composition for laser marking according to any one of items 1 to 4. 6. The relative viscosity of the aromatic polyamide resin is as follows:
The polyamide resin composition for laser marking according to any one of claims 1 to 5, wherein the polyamide resin composition has a ratio of 1.5 to 4.0. 7. The polyamide resin composition for laser marking according to claim 1, wherein the flame retardant other than red phosphorus is a halogen-based flame retardant or a phosphorus-based flame retardant.