JPH01139643A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition with the molding cycle shortened without impairing the mechanical properties, by incorporating a polyamide polymer to be molded with a nucleating agent where a second polyamide polymer higher in the melting point than the former polyamide polymer has been adhered to an inorganic carrier. CONSTITUTION:The objective composition can be obtained by incorporating (A) 100 pts.wt. of a polyamide polymer with (B) 0.05-5 (pref. 0.1-1) pts.wt. of a nucleating agent for molding the polyamide polymer A produced by attaching to B1: 100 pts.wt. of an inorganic carrier (pref. a particulate inorganic carrier with a size of pref. 0.001 to 100mu, esp. 0.1 to 10mu) (e.g., clay, haolin) B2: 5-1,000 (pref. 10-100) pts.wt. of a second polyamide polymer having melting point higher than that of the component A by >=10 deg.C (pref. >=50 deg.C). for example, produced by coupling treatment of the component B1 followed by adding to a solution of the component B2 (with a concentration of 1 to 10wt.%), stirring, centrifuging and vacuum drying.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyamide resin composition that shortens the polyamide resin molding cycle.

(Prior art and its problems) In the molding process of crystalline molding resin, isothermal crystallization is a process in which the high temperature required for molding is rapidly cooled down to the mold temperature, which is kept at a constant temperature. It can be considered as a process. The cooling solidification rate of the resin within the mold corresponds to the isothermal crystallization rate.

Therefore, by shortening the cooling and solidifying process within the mold, the molding cycle can be improved and the production speed can be increased. For this purpose, a method is known in which a nucleating agent is blended as a single polymer modifier to increase the crystallization rate of the molding resin. In polyamide resins, for example, clay minerals such as clay and kaolin (!15 1987-49073)
, arylcarboxylic acid or sulfonic acid (JP-A-59-
13524), polyethylene glycol derivatives (Japanese Patent Publication No. 58-46228), and the like. However, recently it has been used for automobile parts, electrical parts, etc. for the purpose of emphasizing functionality, and accordingly, moldability and
For example, the physical properties of molded products are more important than before.
Nylon, known as a high-performance engineering plastic, has a slower solidification rate on cooling than other nylons and is more expensive, so there is a strong desire to improve production speed by shortening the molding cycle.

In order to further increase the crystallization rate with the conventional nucleating agent listed in L, it is necessary to increase the nucleating agent concentration, but it may cause the physical properties to deteriorate, especially the elastic modulus to increase and become brittle. many. In addition, it has been known for a long time that polyamide polymers, which have a higher melting point than the polyamide resin used for molding, have a significant nucleating effect and increase the crystallization rate. Therefore, it is necessary to raise the molding temperature above the melting point of the polyamide-based polymer used as a nucleating agent. Furthermore, in the molten state, both polyamides undergo an intramolecular transamidation reaction to form a random copolymer, which leads to the formation of a random copolymer. Since it exists as a non-Kt substance in the product, it causes a decrease in physical properties.

Therefore, the V of the polyamide polymer that can be used as a nucleating agent is
! l! The types and molding conditions for their use are significantly limited. In addition, when using a polyamide polymer as a nucleating agent in a solid state, it is necessary to pulverize it to several tens of microns in order to improve dispersibility.
It is difficult and not economical.

Under the above circumstances, there has been a desire for a nucleating agent that can be prepared at low cost, does not cause deterioration in the physical properties of molded products even when used in small amounts, and has a remarkable effect of promoting crystallization.

(Means for Solving the Problems) In order to solve the above problems, the inventor of the present invention has made extensive research and has found a method to improve the molding cycle during injection molding without impairing mechanical properties. We discovered a new nucleating agent and completed the present invention. That is, the present invention provides a polyamide resin composition comprising a polyamide resin molding nucleating agent, which is formed by adhering to an inorganic carrier a polyamide polymer having a melting point 10°C or more higher than that of the polyamide polymer, where j=f. It is related to.

(Structure of the invention) The inorganic carrier applicable to the nucleating agent of the present invention includes:

There are fine particles, fibers, etc. As particulate matter,
It is a grain of silica, galate, carbonate, sulfate, metal oxide, such as clay, kaolin, kaolinite, alumina, talc, bentonite, cloud, thyroid, calcium carbonate, magnesium carbonate, lead carbonate. , calcium sulfate R, titanium oxide, antimony oxide, and magnesium oxide. Also, as a fibrous material,
There are glass fibers, etc. There are also mica, etc. Among these inorganic carriers, fine particles are preferred. The particle size of these inorganic carriers is o, ooi to 100μ, preferably 0.1 to 1
It is 0μ. On the other hand, the polyamide polymer to be attached is
Higher melting point than the polyamide resin to be molded, specifically 10
°C or higher can be selected.

The polyamide polymer applicable to the nucleating agent according to the present invention and the polyamide resin used for molding are both aliphatic polyamides. A polyamide or polyamide copolymer having a high melting point, preferably 50° C. or higher, can be selected. For example, if the polyamide resin to be molded is nylon 12 (melting point 178°C) or nylon-11 (melting point 185°C), nylon 2.2 (350°C), nylon 6 (215”C), nylon 66 <250°C ), nylon 46 (270°C
), nylon 610 (210℃), nylon 612 (2
10'C) can be applied. Regarding the method for preparing the nucleating agent, the amount of the polyamide polymer attached to 100 parts by weight of the inorganic carrier is not particularly limited, but may be from 5 to 1000 parts by weight. More preferably, it is 10 to 100 parts by weight.

If the amount of the polyamide polymer attached is less than 5 parts by weight, only a nucleating effect similar to that of an inorganic carrier can be obtained;
If it is more than 1000 parts by weight, the attached polyamide polymer will separate during melt mixing with the polyamide resin to be molded, resulting in poor dispersibility. As a preparation method, for example, in a 5 wt % solution of the polyamide polymer to be attached,
Examples include adding an inorganic carrier, stirring, centrifuging, and vacuum drying. It is also possible to treat the inorganic carrier with a coupling agent to strengthen the bond with the polyamide polymer to which it is attached, thereby increasing the amount of the inorganic carrier attached. Coupling agents that can be used are, for example, γ-aminepropyltriethoxylane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxy Examples include silane coupling agents such as cyclohexyl)ethyltrimethoxysilane.

The easiest method for preparing a nucleating agent is to add inorganic carrier fine particles to a polyamide polymer solution (<-a 1 to 10 wt%), stir, centrifuge, and vacuum dry. The nucleating agent of the present invention can be treated with a ring agent to strengthen the bond with the polyamide polymer.The nucleating agent of the present invention provides a polyamide resin composition with a shortened molding cycle. The blending ratio of the nucleating agent is 0.05 to 5.0 parts by weight, preferably 0.1 to 1.0 parts by weight, based on 100 parts by weight of the polyamide resin to be molded.

If the blending ratio is less than 0.05 parts by weight, no crystallization promoting effect can be found, and if it is greater than 5.0 parts by weight, the nucleating agent particles cohere together, resulting in a decrease in macroscopic mechanical properties. .

The polyamide resin composition of the present invention includes a stabilizer.

Various additives such as inorganic reinforcing agents can be blended.

(Effect of the invention) When a nucleating agent formed by adhering a polyamide polymer to an inorganic carrier is added to the polyamide resin to be molded at the same weight concentration, it has a more significant effect on promoting crystallization than when the inorganic carrier alone is used. was expressed. In other words, it was found that the time required to reach the peak of the exothermic rate curve obtained in the isothermal crystallization process using the DSC method was 4 to 5 minutes shorter than when using only an inorganic carrier (the measured crystallization temperature temperature 15°C lower than the melting point of nylon resin). This remarkable nucleating agent effect is due to
It is thought that the inorganic carrier also improves dispersibility, and that the polyamide polymer attached to it has epitaxial properties with the polyamide resin to be molded, thereby improving the adhesion between the nucleating agent and the resin. Further, since the nucleating agent according to the present invention can be prepared from a solution, there are many types of polyamide polymers that can be selected as the nucleating agent if a suitable solvent is found.

Example The effects of the invention will be further explained using examples.

(Evaluation of crystallization rate) The crystallization rate of the resin due to the combination of nucleating agent was measured using a differential scanning calorimeter (P
Evaluation was made based on the time (tnax) taken to reach the peak of the exothermic rate curve obtained from isothermal crystallization measurement using ERKIN-ELHER DSC-2C). For measurement, the sample was heated to 220°C.
After melting for 3 minutes, it was rapidly cooled at 320°C/nin and maintained at a crystallization temperature of 162°C. The origin of crystallization time is 162℃
After the temperature control lamp of the DSC main body was turned on when the temperature was rapidly cooled to 1, the time 18 seconds later was set to zero.

The melting point of the crystalline polymer was maintained at a constant rate temperature increase measurement (10° C./min) using a differential scanning calorimeter (DSC). The origin of the crystallization time was set to zero at the time 18 seconds after the temperature control lamp of the DSC main body was turned on at the time of rapid cooling to 162°C.

The melting point of the crystalline polymer was determined by the temperature of the crystal melting peak obtained by constant rate temperature increase measurement using a differential scanning calorimeter (DSC).

Synthesis example-1 Nylon 6 pellet 13.4. (dissolved in 200 ml of formic acid (51%)), 1-3 micron clay (Hani Chemical standard activated clay AI 0.6SiO7.H2OJ
) and stirred for 5 hours. Next, this suspension was centrifuged, the supernatant was removed, and the suspension was
It was vacuum dried at ℃ for 3 hours to obtain nylon 6-attached clay particles. The nylon 6 deposit of this particle was 18v4t% as determined by TG-DTA thermal analysis.

Example-1 Nylon 12 (Daicel-Hüls “Diamid Ll”)
901J) and 0.1 g of a nucleating agent consisting of the nylon 6-adhered clay obtained in Synthesis Example 1 were kneaded for 3 minutes at a set temperature of 220° C. in a Gravender type experimental mixer. The crystallization rate of the obtained sample was evaluated by DSC method. The results obtained are shown in Table 1.

Synthesis Example 2 and Example 2 Nylon 66-attached clay particles were prepared from Nylon 66 and clay in the same manner as in Synthesis Example 1. The amount of nylon 66 attached to these particles was 14 wt%) DSC measurement A sample was obtained. (Table 1) Synthesis Example 3 and Example 3 Nylon 46-adhered clay particles were prepared in the same manner as in Synthesis Example 1 using nylon 46 and clay (nylon 46 adhesion amount: 20 wt%), and 0.1 g of nylon 12 A sample for DSC measurement was obtained by mixing with. (Table 1) Comparative Example-1 Similarly to Example 1, 0.1 g of clay was mixed with nylon 12 to prepare a sample for DSC measurement. (Table 1) Comparative Example-2 Similar to Example 1, Nylon 460.1. Nylon 12
was mixed to prepare a sample for DSC measurement. (Table Comparative Example-3 Same as Example 1, clay 〇, OS g and nylon 46
0.02 g of the mixture (same composition ratio as the nylon 46-attached clay obtained in Example 3) was mixed with nylon 12 to prepare a sample for DSC measurement.

(Table 1) (Impact properties) The nylon 6-adhered clay (nucleating agent) prepared in Synthesis Example 1 and the clay were mixed with nylon 12 (Li2O2>0.2
Calcium stearate 0.5ph as phr lubricant
r, dioctyl adipate 0.2 phr, tetrakis-[methylene-(4-hydroxy-3,5
-di-t-butyl-hydrocinnamate) comethane 0.
The mixture to which 2 phr was added was kneaded and extruded into pellets using an extruder. This nylon 12 composition was injection molded under the following molding conditions, and its Izot fff impact strength was measured in accordance with ASTM D256. Measured at 25℃
The tests were conducted in an air-conditioned room with a humidity of 60%.

The results are shown in Table 2.

[Molding conditions] Molding machine Sumitomo Heavy Industries, Sumitomo Nestal injection pressure
70kgf/a & (gauge pressure) injection speed 3n
/sec Mold temperature 23℃ Cooling time 25 seconds Table 2 Patent application Hitoshi Taisel Chemical Industry Co., Ltd.

Claims (1)

[Claims] A polyamide resin composition characterized in that a nucleating agent for polyamide resin molding is blended into a polyamide polymer and a polyamide polymer having a melting point 10° C. or higher higher than that of the polyamide polymer is attached to an inorganic carrier.