JPS5876431A - Polyamide resin composition for expansion molding - Google Patents

Abstract

PURPOSE:The titled resin composition having improved surface characteristics, heat resistance and physical and chemical properties, by incorporating a polyamide obtained from m-xylenediamine and adipic acid as principal raw materials with a fibrous reinforcing material and a decomposition type foaming agent in a specific proportion. CONSTITUTION:A composition obtained by incorporating a resin component (the rest is a mixable thermoplastic resin and nylon, etc.) containing 85wt% polyamide prepared by polycondensing a diamine component containing 70mol% or more m-xylenediamine (the rest is an aliphatic diamine) and a dicarboxylic acid component containing 80mol% or more adipic acid (the rest is an aliphatic dicarboxylic acid) with 5-70wt%, preferably 10-50wt%, based on the resin component, fibrous reinforcing material, e.g. glass fibers, and 0.1-5.0wt%, based on the two materials, decomposition type foaming agent e.g. azodicarbonamide. A pigment, flame retardant, etc. are if necessary added thereto, and the resultant mixture is then expansion molded at a desired expansion ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyamide resin composition for foam molding that has excellent surface properties, heat resistance, and physical and chemical properties.

Regarding polyamide foaming technology, several methods are already known, and various polyamide low foams or shima foams are being used. In particular, molded products obtained from compositions consisting of fibrous reinforcement, decomposable foaming agents, and polyamides such as nylon 66 and nylon Otsu are likely to be applied to fields that require high functionality, such as automobile electrical equipment parts. It is estimated that the demand for Shimamari will increase significantly in the future. However, currently available polyamide foam molded products do not necessarily have satisfactory properties such as mechanical properties, surface smoothness, paintability, color, etc.

The foamed molded article obtained from the composition of the present invention has excellent smoothness that can withstand baking painting and metal vapor deposition, chemical resistance, heat resistance, and mechanical properties.

The first characteristic of the foam obtained from the composition of the present invention is that it has extremely smooth surface properties and extremely uniform foaming inside. Conventionally obtained foam molded products have many flow marks and sink marks and have poor surface conditions.For molded products with such flow marks and sink marks, surface finishing such as sanding is necessary before painting. This requires a considerable amount of time and effort, resulting in a significant decrease in the productivity of molded products. Excellent smoothness not only makes surface treatment and painting work more efficient before painting, but also
Sometimes it is possible to omit the painting itself.

The first feature of the foam molded product obtained from the composition of the present invention is that it has an extremely high expansion ratio and excellent mechanical properties. It is well known that molded products obtained from molding materials blended with fibrous reinforcing materials such as glass fibers have high strength and high modulus over a wide temperature range. However, conventional polyamides such as nylon 6 and nylon 66 are Compared to the fact that the polyamide foam molded product as a component cannot fully exhibit the physical properties expected from a non-foamed molded product, the molded product obtained from the composition of the present invention is not as good as a non-foamed product such as a normal injection molded product. It is surprising that higher physical property values can be obtained than expected from a molded article. This is presumed to be due to the fact that molded articles with extremely uniform foamed structure and excellent surface smoothness can be obtained from the composition of the present invention. The reason why a molded article having an extremely uniform foam structure, a high expansion ratio and excellent surface properties can be obtained from the composition of the present invention has not yet been precisely elucidated. However, the air bubble retention effect due to the intertwining of the fibrous reinforcing materials and the properties of the polyamide whose main ingredients are metaxylylene diamine and adipic acid, which are the main components of the composition of the present invention, are ,
It is also presumed that in addition to having an appropriate effect on crystal solidification and the formation of a surface skin layer, the polyamide foam membrane has an appropriate gas permeability, which is advantageous.

The third feature of the present invention is the excellent heat resistance of the composition of the present invention and the foam molded products obtained from the composition of the present invention.
The composition of the present invention is extremely stable to heat during molding, so it does not undergo thermal deterioration and maintains excellent physical properties, and the molded product exhibits a beautiful milky white color without any coloration.

Molded products made of polyamide obtained using meta-silylene diamine and adipic acid as main raw materials reinforced with glass fiber, etc. (RKNY: Samugi Gas Chemical ■trade name) are 2.
It is known to have a heat distortion temperature (,2647 psi) of 20° C. or higher. However, the foaming ratio is /, I
! It is completely unpredictable and surprising that the heat distortion temperature of 190°C or higher is maintained even after reaching the temperature of The molded article can withstand long-term thermal history of 30 to 20 minutes at high temperatures of iso to /10°C.

This further enhances the significance of the present invention. The diamine component used in the present invention contains metaxylylene diamine in an amount of at least 70 moles, and if desired, the remainder may be tetramethylenecyamine, pentamethylene diamine, etc. Aliphatic diamines such as amine, hexamethylene diamine, octamethylene diamine, nonamethylene diamine; Aromatic diamines such as para-xylylene diamine, para-phenylene diamine: l,3-bisaminomethylcyclohexane, /, Hiro-bisaminomethylcyclohexane One or more types of diamines listed as alicyclic diamines can be appropriately selected and used.

The dicarboxylic acid component used in the present invention contains adipic acid in an amount of at least tOmole, and I! ! 4s is succinic acid, glutaric acid, pimelic acid, speric acid, aze2
One or more types of aliphatic dicarboxylic acids such as inic acid, sebacic acid, undecanechoic acid, and dodecanedioic acid may be selected as desired.

In addition to the polyamide obtained by polycondensing these diamine components and dicarboxylic acid components, the resin components used in the composition of the present invention include various thermoplastic 11 resins that can be blended with this polyamide. , can be used in an amount less than /j weight - based on the entire resin component,
Examples of such thermoplastic resins include various nylons such as nylon 6, nylon 66, and nylon 610, as well as polyphenylene sulfide, polysulfone, polyphenylene oxide, polyacetal, polyethylene, polypropylene, etc. If the proportions of the acid component and the resin component deviate from these, the desired effect cannot be achieved.

All known decomposable blowing agents can be used as the decomposable blowing agent used in the present invention, and specific examples include azodicarbonamide, benzenesulfonyl semicarbazide, P-toluene, sulfonyl semicarpazide, Bis(benzenesulfonyl)hydrazide, p, p'-
Examples include oxybis (benzenesulfonyl semicarbazide) and basic zinc carbonate. The blending amount of the decomposable foaming agent is 0,/~j, Omt* with respect to the total amount of the fat component and the fibrous reinforcing material in the composition, as in the usual case.

The fibrous reinforcing material used in the present invention includes glass fiber,
Carbon fiber, gold maple or inorganic whiskers can be drilled. Particularly preferred is the use of glass fiber. The blending of the fibrous reinforcing material is j~70wt-1 especially /θ~s with respect to the resin component.
If on is less than the appropriate Oj weight, the surface smoothness and heat resistance cannot be sufficiently improved, and if it is more than 70 weight, it is difficult to blend.

The preparation of the composition of the present invention is '! 148″#, a method of blending a decomposable foaming agent and a fibrous reinforcing material immediately before molding, a method of blending a foaming agent into a resin composition containing a fibrous reinforcing material, a resin containing a high concentration decomposable foaming agent Well-known methods such as a method of blending the composition with the fibrous reinforcing material-containing resin used in the present invention can be employed.

Composition of the present invention Kjli family, flame retardant, inorganic filler lubricant,
It is possible to add ultraviolet absorbers, crystallization nucleating agents, heat stabilizers and other stock additives as long as they do not interfere with the object of the present invention.

The composition of the present invention can be molded to a desired foaming rate by conventional thermoplastic resin molding methods such as injection molding, extrusion molding, and blow molding.

The present invention will be specifically described in detail in the following examples.0 Example/ 80 m of azodicarbonamide was mixed into a molding material consisting of 30 parts of glass fiber and 70 parts of metaxylylene adipamide using a Henschel mixer, and then injected. The molding machine (Niigata Tekko 8N-/DO with shut-off nozzle and back pressure holding device) was supplied, and the cylinder temperature - JIC1 mold temperature was adjusted at 130°C, as shown in the M/table from K. AEIT with foaming ratio of ”/a x ”/2 x 5 inches
A test piece for the M-type test was molded. The physical properties and surface condition of the obtained test piece are shown in Table 1. Example 30 parts of co-glass fiber and 66.5 parts of metaxylylene adipamide
A composite material consisting of 443.5 parts of nylon, and 13 parts of basic zinc carbonate was molded using an injection molding machine (N-/DO from Niigata Steel) K.
A rectangular plate-shaped test piece of 70 x 7 o x 7 m was molded by adjusting the sample supply scale at cylinder temperature JJJ°C and mold temperature /JO°C. Table 2 shows the physical properties and surface condition of the test piece obtained.

Town Table 2 Example 3 30 parts of glass fiber and copolymerized polyamide resin [methaxylylene diamine and bar 5-? Resin obtained by polycondensation of mixed xylylene diamine (mole ratio 8/2) with silylene diamine, a mixture of adipic acid and sebacic acid, and dicarboxylic acid (mole ratio 9/1) j 6.5 parts , nylon 66
The molding material consisting of 3.5 parts was mixed with a t,os azodicarbonate mixer and then put into an injection molding machine (
Shut-off nozzle with back pressure retaining lid E1 manufactured by Niigata Iron Works
m-100), the cylinder temperature is 60℃, the mold temperature is 13θ℃, and the sample supply scale is adjusted to 1.0 from K! -1/4X with a foaming ratio of 2,00x
A 1/2×5 inch A8TM 8-section test piece was molded. All of the test pieces obtained had heat distortion temperatures of 100° C. or higher and excellent surface characteristics with no 7o marks.

Patent applicant: Mitsubishi Gas Chemical Co., Ltd. Representative Kazuyoshi Nagano

Claims (1)

[Claims] ゛The polyamide obtained by polycondensing a diamine component containing 70 moles or more of metaxylylene diamine and a dicarboxylic acid component containing 10 moles or more of adipic acid is rz@
It consists of a resin component containing more than 10%, a fibrous reinforcing material, and a decomposable foaming agent, and the blending ratio of the fibrous reinforcing material is 5 to 70% by weight relative to the resin component, and the blending ratio of the decomposable foaming agent is a.
The total amount of fat component and fibrous reinforcing material (7 and 0./
-j, O@@ A polyamide resin composition for foam molding that is arrogant.