JPH0723448B2 - Polyamide resin composition - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a polyamide resin composition having excellent moldability.

More specifically, the present invention relates to a polyamide resin composition capable of giving excellent productivity during injection molding and efficiently obtaining a good molded product with few defects.

[Conventional technology and problems]

Polyamide resin has excellent heat resistance, mechanical properties, chemical resistance,
It is useful as an engineering resin having features such as abrasion resistance.

This polyamide resin is usually easily molded,
In recent years, from the viewpoint of productivity and economical efficiency, there has been a strong demand in the art to obtain a composition which can be stably molded with higher efficiency without impairing the above-mentioned basic characteristics.

Generally, when high-speed molding is performed to increase productivity, molding troubles such as mold release failure and instability of plasticization time occur, and defects such as bubbles and deformation are likely to occur in the molded product. On the other hand, it becomes difficult to increase productivity in order to obtain a stable and good molded product.

Thus, in the case of attempting to improve the productivity, a polyamide resin composition capable of simultaneously obtaining excellent molding processability and a good molded product with few defects at the same time has not been achieved by the prior art.

The polyamide compounded with an engraving agent has an increased crystallization rate, and as a result, productivity is improved. As engraving agent, Graphite,
Substances such as molybdenum disulfide and gold layer halides, or fatty acid metal salts such as calcium stearate, magnesium stearate and lithium oleate, and
Phosphonic acid, phosphinic acid, and their derivatives are known.

In Japanese Examined Patent Publication No. 59-8300, by mixing and using an organic phosphonic acid compound and a saturated or unsaturated fatty acid metal salt,
It is disclosed that a further improved nucleation effect is obtained.

That is, the polyamide composition according to this proposal exhibits a nucleating effect which is more advanced than that of a single composition containing a nucleating agent, and as a result, a high production rate of molded articles is achieved.

However, even if the production speed is increased, if the quality of the obtained molded product is insufficient or the stability at the time of molding is insufficient, it cannot be said that comprehensive and useful productivity was obtained.

According to the method of Japanese Patent Publication No. 59-8300, for example, a molded product having a complicated shape may have breakage cracks and mold release defects at the time of mold release. Also, in the case of molding such as large-scale or multi-cavity molding in which the amount of resin per one shot is large and the amount of plasticization is large, the plasticization time becomes rate-determining, so the crystallization rate by the nucleating agent increases. Is not exhibited, and it becomes difficult to shorten the molding cycle, that is, to achieve improvement in productivity.

In the specification of Japanese Patent Publication No. 54-4742, by using a salt of an aliphatic carboxylic acid having 10 to 20 carbon atoms and an aliphatic carboxylic acid having 22 or more carbon atoms, or a derivative thereof, in combination, It is described that the releasability is improved.

According to this method, the mold releasability is improved, but when the molding cycle time is shortened and the productivity is increased, defects such as bubbles, deformation and sink marks are generated in the molded product.

Further, it is known to use a metal salt of an aliphatic carboxylic acid as a method for shortening the plasticizing time. In this method, the plasticizing time is shortened, but when the cycle time is shortened, bubbles or deformation occur in the molded product. It also causes defects such as sink marks.

That is, a polyamide resin composition capable of improving productivity and efficiently obtaining a molded article with few defects has not been achieved by the conventional technique.

[Means for solving problems]

The present inventors, in order to improve the productivity at the time of injection molding, give excellent molding processability even when the molding cycle time is shortened, and at the same time, provide good molded products with few defects. As a result of extensive studies on a polyamide resin composition that can be efficiently obtained, one or more compounds selected from the group consisting of organic phosphonic acids, organic phosphinic acids, and metal salts thereof for polyamide resins. In addition, when the aliphatic carboxylic acid sodium salt having 22 or more carbon atoms is added together, the above problems are specifically eliminated and the molding cycle time is shortened in order to improve the productivity during injection molding. Even in these cases, the present invention has been accomplished by finding a polyamide resin composition which has excellent molding processability and can efficiently obtain a good molded product with few defects.

That is, the present invention comprises 100 parts by weight of a polyamide resin, 0.0005 to 0.4 parts by weight of one or more compounds selected from the group consisting of organic phosphonic acids, organic phosphinic acids, and metal salts thereof, and an aliphatic having 22 or more carbon atoms. Carboxylic acid sodium salt 0.02-0.
A polyamide resin composition comprising 5 parts by weight is provided.

Known polyamide resins can be used as the polyamide resin applied to the present invention. For example, various types of polyamide resins such as polycondensates of lactams, polycondensates of diamine compounds and compounds having a dibasic acid, polycondensates of ω-aminocarboxylic acids, or copolymerized polyamide resins thereof, or blends thereof. Etc., for example, homopolymers such as nylon 6, 66, 610, 11, 12 and the like, copolymers such as nylon 66/6, 66/610, 66/612, 66 / 6T and mutual blends thereof.

The first additive applied to the present invention is an organic phosphonic acid,
Organic phosphinic acids, and metal salts thereof, specifically, for example, phenylphosphonic acid, sodium phenylphosphonate, zinc phenylphosphonate, cyclohexylphosphonic acid, benzylsulfonic acid, phenylphosphinic acid, phenylphosphinic acid. Examples thereof include sodium salt and zinc phenylphosphinic acid salt.

The range of the amount added of these is limited in terms of their effects. That is, if less than 0.0005 parts by weight with respect to 100 parts by weight of polyamide resin, the desired effect is small, and
Even if it exceeds 4 parts by weight, the desired effect cannot be obtained, so 0.0
A range of 005 to 0.4 parts by weight is required, preferably 0.001
To 0.2 parts by weight, more preferably 0.003 to 0.1 parts by weight.

The second additive applied to the present invention is a sodium salt of an aliphatic carboxylic acid having 22 or more carbon atoms, specifically, for example, sodium salts such as behenic acid, lignoceric acid, cerotic acid, montanic acid, and meridinic acid. For example, Hostalub TM NaW-1 and Hostalub VP N manufactured by Hoechst Japan.
Industrial montanic acid sodium salt such as aW-2 is preferably used.

The range of the amount of addition of these substances is limited in their action and effect. That is, if less than 0.02 parts by weight with respect to 100 parts by weight of polyamide resin, the desired effect is small, and 0.5
0.02 as the desired effect cannot be obtained even if the amount exceeds
~ 0.5 parts by weight is required, preferably 0.04 to 0.3
The range is parts by weight.

As the method for producing the polyamide resin composition of the present invention,
Was added to the monomer to polymerize, added during the polymerization, melt-kneaded with an extruder or the like, adhered to the surface of the polymerization pellet, and added at a high concentration by a polymerization vessel, an extruder, etc. A method such as blend addition of masterbatch pellets is used.

The second additive can be added in the same manner as the first additive, but by adhering a part of the total amount of the second additive to the pellet surface, the effect of the present invention is further improved. validate. The amount of the second additive attached to the surface of the pellet is preferably at least 0.02 part by weight or more. However, the total amount of the additives, including those adhering to the surface, is within the range of 0.02 to 0.5 part by weight based on 100 parts by weight of the polyamide resin. As a method of adhesion, dry blending using a blender or the like, blending using blending oil such as mineral oil or polyethylene glycol, or coating on the pellet surface is preferred.

The composition of the present invention may contain known substances such as stabilizers such as copper compounds, antioxidants or coloring agents such as sulfur compounds, fillers and reinforcing agents.

〔Example〕

Examples and comparative examples are shown below, but the present invention is not limited to these examples.

Examples 1 to 14 and Comparative Examples 1 to 8 With respect to 100 parts by weight of nylon 66 pellets, various additives shown in Table 1 were mixed with a tumbler type blender for 5 minutes to obtain polyamide resin composition pellets,
In injection molding when the molding cycle was shortened, the plasticizing time and the releasing force were measured, the deformation amount of the molded product was measured, the bubble generation rate was observed, and the elongation at break of the molded product was measured.

(1) Plasticization time (molding conditions) Injection molding machine: PS-40E made by Nissei Plastic Co., Ltd. Mold: 4 pieces connector Cylinder temperature: Nozzle 280 ° C, front 280 ° C, middle 280
℃, rear 275 ℃ Mold temperature: 75 ℃ ~ 80 ℃ Plasticization stroke: 55 mm Screw rotation speed: 200 rpm Injection pressure: Primary pressure 950kg / cm ² Injection time: 4 seconds Cooling time: 10 seconds (Measurement method) 41 from the start of molding The average value and the deviation value of the plasticizing time from the eyes of the shot to 90 shots were measured.

(2) Mold release force (molding conditions) Injection molding machine: Toshiba Machine IS-90B Mold: Cup-shaped molded product (1 piece) Cylinder temperature: Nozzle 280 ° C, front 280 ° C, central 280
℃, the rear 280 ℃ Mold temperature: 75 ℃ ~ 80 ℃ Injection pressure: 400kg / cm ² Injection time: 4 seconds Cooling time: 10 seconds (Measuring method) The mold with the mold release force measuring device shown in Fig. 1 is attached. Molding was carried out under the above-mentioned molding conditions, and the average value of the releasing force from 31st to 5th cuts was measured. 1 in FIG.
Is a nozzle of an injection molding machine, 2 is a sprue runner, 3 is a molded product (copper shape), 4 is an ejector pin, 5 is an ejector plate, 6 is a pressure sensor, 7 is a knockout rod, 8 is a cavity, and 9 is a cavity. The core, 10 is a release force recorder.

(3) Deformation amount (molded product) A connector molded product shown in the schematic view of Fig. 2 was obtained at the time of measuring the plasticizing time.

(Measurement Method) The outer dimension at the x position and the outer dimension at the y position in FIG. 2 were measured, and the difference was defined as the amount of deformation. (A) The figure is a side view of the connector,
FIG. 6B is a front view of the same. (B) The units of the numbers in the figure are
mm.

(4) Bubble Generation Rate (Molded Product) The connector molded product obtained at the time of measuring the plasticization time was used.

(Measurement method) Molded products containing air bubbles were selected from 50 connectors and shown as a ratio.

(5) Elongation (molding conditions) Injection molding machine: Toshiba machine IS-50EP Mold: ASTM D638 Type1 tensile test piece Cylinder temperature: Nozzle 280 ° C, front 280 ° C, central 280
℃, rear 275 ℃ Mold temperature: 75 ℃ ~ 80 ℃ Injection pressure: 405kg / cm ² Injection time: 4 seconds Cooling time: 10 seconds (Measurement method) Tensile test piece obtained under the above molding conditions in a 23 ℃ desiccator After standing for 48 hours, the tensile elongation at break was measured.

Example 15 The procedure of Example 1 was repeated except that the first additive was added during the polymerization of nylon 66.

Example 16 20-fold amount of the first additive was blended with nylon 66 pellets, and then melt kneading and extrusion were performed using an extruder, and the master batch pellets were diluted to 1/20 with nylon 66 pellets. It carried out like Example 1.

Example 17 The same procedure as in Example 1 was carried out except that the first additive was blended with nylon 66 pellets and the mixture was melt-kneaded and extruded using an extruder to form pellets.

Example 18 After 0.005 parts by weight of the first additive and 0.05 parts by weight of the second additive were blended with 100 parts by weight of nylon 66 pellet, melt kneading extrusion was carried out using an extruder to form pellets and then the second additive. The same procedure as in Example 1 was carried out except that 0.05 part by weight of the additive was mixed with a tumbler type blender for 5 minutes and adhered to the surface of the pellet.

Example 19 The same procedure as in Example 1 was carried out except that the first additive and the second additive were blended with nylon 66 pellets and then melt-kneaded and extruded using an extruder to form pellets.

Example 20 After the second additive was blended with nylon 66 pellets, melt kneading extrusion was performed using an extruder to pelletize,
Further, the same procedure as in Example 1 was carried out except that 0.005 parts by weight of the first additive was mixed with a tumbler type blender for 5 minutes and adhered to the surface of the pellet.

〔The invention's effect〕

From the results of Examples and Comparative Examples, the composition of the present invention has excellent molding processability such as shortening and stabilization of the plasticizing time, small release force, and the like, deformation of the molded product, less bubbles, and breakage. It is possible to efficiently obtain a good molded product with few defects such as a decrease in elongation, and as a result, productivity can be greatly improved.

[Brief description of drawings]

FIG. 1 is a schematic view of a mold equipped with a mold release force measuring device used for measuring mold release force and an injection molding machine in Examples and Comparative Examples. FIG. 2 is a schematic view of a connector molded product used for measuring plasticization time and deformation amount and observing bubbles in Examples and Comparative Examples. 1 ... Nozzle of injection molding machine 2 ... Sprue runner 3 ... Molded product (cup shape) 4 ... Ejector pin 5 ... Ejector plate 6 ... Pressure sensor 7 ... Knockout rod 8 ... Cavity 9 ... Core 10-Release force recorder

Claims (1)

[Claims] 1. A polyamide resin 100 parts by weight and 0.0005 to 0.4 parts by weight of one or more compounds selected from the group consisting of organic phosphonic acids, organic phosphinic acids, and metal salts thereof.
Aliphatic carboxylic acid sodium salt having 22 or more carbon atoms 0.02 to 0.
Polyamide resin composition consisting of 5 parts by weight