JP2002030215A - Reinforced polyamide resin composition excellent in welding strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reinforced polyamide resin composition excellent in fluidity and high cycling properties when molding and having a high welding strength in various kinds of welding methods. SOLUTION: This reinforced polyamide resin composition for molding excellent in strength of welded parts comprises (A) 100 pts.wt. of a crystalline polyamide resin having >=60 milliequivalents amino end group concentration based on 1 kg of the polymer and (B) 5-200 pts.wt. of an inorganic filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforced polyamide resin composition having excellent mechanical properties and moldability and having excellent welding strength. These resin compositions are used as materials for automobiles and electric and electronic parts.

[0002]

2. Description of the Related Art Crystalline polyamide resins are widely used as industrial materials because of their high strength and rigidity.
However, reinforced polyamides that use only crystalline polyamides as the polyamides have a high welding strength due to their crystallinity.In recent years, when welding, which has become widely used when manufacturing resin parts, is performed, the strength of the portions is not sufficient. The use for parts that require it has been limited.

[0003] With respect to techniques for improving the welding strength of crystalline polyamide, various studies have been made with the increase in the number of parts using welding in recent years. JP-A-9-17648
No. 4, JP-A-10-219106 proposes a method for improving the weldability of nylon using copper iodide and potassium iodide. However, this method has problems such as a decrease in mechanical strength and generation of a decomposition gas at the time of molding due to a large amount of potassium iodide and copper iodide actually used. JP-A-8-3377
No. 18 proposes a method using crystalline copolymerized nylon, but when copolymerized nylon is used, the weldability is significantly improved, but the mechanical strength and rigidity are reduced and heat resistance is reduced. The use is limited because the durability decreases.

[0004] Inventions relating to polyamides having a high amino group concentration as used in the present invention have been disclosed before the present invention. For example, Japanese Patent Publication No. 9-507426 discloses a technique for improving hydrolysis stability by using a polyamide having a high amino group concentration, and Japanese Patent Application Laid-Open No. 8-3443 discloses a technique for improving hot yellowing. However, in these inventions, there is no description to improve the welding strength of the inorganic filler reinforced product as in the present invention, and it is completely known that the effect of improving the weldability can be obtained in the composition range of the present invention. Not.

[0005]

DISCLOSURE OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a reinforced polyamide resin composition which is excellent in fluidity and high cycle property at the time of molding and has high strength by various welding methods. It is to provide.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve this problem and as a result, have found that the object can be achieved by using a crystalline polyamide having an amino terminal group concentration of a certain amount or more. The invention has been reached.

That is, the present invention provides: (A) 100 parts by weight of a crystalline polyamide resin having an amino terminal group concentration of 60 milliequivalents or more per 1 kg of a polymer; and (B) strength of a welded portion having an inorganic filler of 5 to 200 parts by weight. The present invention relates to a reinforced polyamide resin composition for molding which has excellent properties.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The (A) crystalline polyamide resin used in the present invention is an aliphatic polyamide resin composed of lactam or aminocarboxylic acid.

The monomer component of the aliphatic polyamide resin includes lactams having 6 to 12 carbon atoms or 6 to 12 carbon atoms.
12 aminocarboxylic acids. Specific examples of lactams include α-pyrrolidone, ε-caprolactam, ω-laurolactam, ε-enantholactam, and specific examples of aminocarboxylic acids include 6-aminocaproic acid, 7-aminoheptanoic acid, Examples thereof include -aminoundecanoic acid and 12-aminododecanoic acid, and 6-aminocaproic acid, 12-aminododecanoic acid, ε-caprolactam, and laurolactam are preferred. The aliphatic polyamide-forming monomer may be used alone or as a mixture of two or more components.

Specific examples of the aliphatic polyamide resin formed from these monomer components include nylon 6, nylon 11, and nylon 12, which may be a homopolymer or a copolymer of two or more.

Although the degree of polymerization of the crystalline polyamide resin in the present invention is not particularly limited, 1 g of the polymer is dissolved in 100 ml of 96% concentrated sulfuric acid, and the relative viscosity measured at 25 ° C. is 1.8 to 5.0. It is more preferably, and more preferably 2.0 to 3.0. When the relative viscosity is higher than the upper limit of the above numerical value, the workability is significantly impaired.

A feature of the present invention is that the terminal amino group concentration of the above-mentioned polyamide resin is contained in 60 kg or more per 1 kg of the polymer. The method for producing a polyamide resin having a high characteristic amino group concentration is not particularly limited, but is obtained by including a diamine compound when the composition is extrusion-kneaded during or after polymerization. Can be. If it is produced at the time of melt polymerization, a method of adding and adding a diamine monomer excessively at the time of charging the raw material, a method of adding and mixing a diamine compound other than the raw material monomer and the raw material monomer at the time of charging the raw material, and a method of polymerizing a polyamide having a predetermined molecular weight. After that, a method is used in which a diamine compound is added just before the polymer is extracted from the polymerization tank so that the target terminal group concentration is balanced. If it is manufactured after the polymerization, a method of melt-kneading the polyamide resin and the diamine compound after the polymerization so as to achieve a target terminal group concentration balance is used.

Specific examples of the diamine compound include, in addition to those used as the above-mentioned polyamide resin monomers, aliphatic diamines such as methylene diamine, ethylene diamine, trimethylene diamine, and aromatic diamines such as naphthalenediamine and meta-xylylenediamine. Diamines are used, and preferably hexamethylenediamine, dodecamethylenediamine, and meta-xylylenediamine.

In order to achieve the object of the present invention, the terminal amino group concentration required for the polyamide resin is required to be at least 60 meq / kg, preferably at least 90 meq / kg, to further enhance the effects of the present invention. it can.

The (B) inorganic filler used in the present invention comprises:
Fibrous inorganic materials such as glass fiber and carbon fiber, wollastonite and potassium titanate whisker, montmorillonite, talc, mica, calcium carbonate, silica, clay, kaolin, glass powder, glass beads, and other inorganic fillers, various organic or An organic filler such as a polymer powder may be used, but glass fiber or talc is preferably used, and glass fiber is more preferable. The fibrous filler has a fiber diameter of 0.01 to 20 μm, preferably 0.03 to 15 μm, and a fiber cut length of 0.5 to 0.5 μm.
10 to 10 mm, preferably 0.7 to 5 mm.

The amount of the inorganic filler (B) used in the present invention is based on 100 parts by weight of the obtained polyamide resin.
The amount is 5 to 200 parts by weight, preferably 10 to 150 parts by weight, more preferably 10 to 100 parts by weight. If the amount is less than 5 parts by weight, the mechanical strength of the polyamide resin is not sufficiently satisfied. If the amount is more than 200 parts by weight, the mechanical strength is sufficiently satisfied, but the moldability and the surface condition deteriorate, which is not preferable.

Although the resin composition of the present invention can be used as it is as a material for automobiles and electric / electronic parts, heat-resistant agents, weathering agents, crystal nucleating agents, crystallization accelerators, release agents are used as long as their purposes are not impaired. Functionality-imparting agents such as a mold agent, a lubricant, an antistatic agent, a flame retardant, a flame retardant auxiliary, and a coloring agent can be used.

More specifically, hindered phenols, phosphites, thioethers,
Copper halide and the like can be mentioned, and these can be used alone or in combination. Examples of the weathering agent include hindered amines and salicylates, which can be used alone or in combination. As a crystal nucleating agent, talc,
Examples include inorganic fillers such as clay and organic crystal nucleating agents such as fatty acid metal salts, and these can be used alone or in combination. Examples of the crystallization promoter include low molecular weight polyamides, higher fatty acids, higher fatty acid esters and higher fatty alcohols, and these can be used alone or in combination. Release agents include fatty acid metal salts,
Examples thereof include fatty acid amides and various waxes, which can be used alone or in combination. Examples of the antistatic agent include aliphatic alcohols, aliphatic alcohol esters and higher fatty acid esters, and these can be used alone or in combination. Flame retardants include metal hydroxides such as magnesium hydroxide, phosphorus, ammonium phosphate, ammonium polyphosphate, melamine cyanurate,
Ethylene dimelamine dicyanurate, potassium nitrate, brominated epoxy compound, brominated polycarbonate compound,
Brominated polystyrene compounds, tetrabromobenzyl polyacrylate, polycondensates of tribromophenol, polybromobiphenyl ethers and chlorine-based flame retardants,
They can be used alone or in combination.

Other thermoplastic resin compositions can be added to the resin composition of the present invention as long as the object of the present invention is not impaired. Examples of the thermoplastic resin used in combination are polyethylene, polypropylene, polystyrene, ABS resin, A
General-purpose resin materials such as S resin and acrylic resin, aliphatic polyamide resins such as nylon 6, nylon 66, and nylon 12 other than (A) used in the present invention, polycarbonate,
Examples include polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, and other high heat resistant resins. In particular, when polyethylene or polypropylene is used in combination, it is desirable to use those modified with maleic anhydride, a glycidyl group-containing monomer, or the like.

The resin composition of the present invention is produced by a known method. Generally, the polyamide resin composition of the present invention is obtained by melt-kneading a polyamide resin and an inorganic filler using a kneader. Examples of the kneader include an extruder such as a single-screw extruder and a twin-screw extruder, a twin-screw continuous mixer, a Banbury mixer, a super mixer, a mixing roll, a kneader, and a Brabender plastograph. The polyamide resin composition of the present invention can be used for extrusion molding, blow molding or injection molding.

When the polyamide resin composition of the present invention is used for a product using a welding method, its performance can be remarkably exhibited, but is not limited thereto. Specific examples of the welding method include a vibration welding method, an injection welding method such as die slide injection (DSI) and a die rotary injection (DRI), an ultrasonic welding method, a spin welding method, a hot plate welding method, a hot wire welding method, and a laser welding method. And a high-frequency induction heating welding method.

Further, the composition of the present invention exhibits its performance also in products having a melt-bonded portion such as a multicolored molding or a weld portion.

The composition of the present invention can be used for engines of automobiles and motorcycles, transmissions, differential mechanism parts, chassis parts, exterior parts, interior parts and electric parts,
Can be used for electric and electronic parts. Specific examples include oil strainers, timing chain covers, rocker covers, intake manifolds, fuel rails,
Timing chain tensioner, thrust washer, power steering tank, brake fluid sub tank, canister, automatic transmission stator, air cleaner, resonator, vacuum tank, throttle body, radiator tank, thermostat housing, radiator inlet pipe, radiator outlet pipe, gear, retainer, Mechanical parts such as front end, headlight stay, lower arm, link, etc., hollow parts such as air duct, gasoline tank, brake pipe, fuel pipe, etc.
Examples include pedals such as an accelerator pedal, a brake pedal, and a clutch pedal, electric components such as a sensor, a relay box, and a connector, and electric and electronic components such as a terminal block, a connector, and a relay.

[0024]

The present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples. The measurement of the physical properties of the molded articles in Examples and Comparative Examples was performed as follows.

(Evaluation of physical properties) (Evaluation of mechanical properties) Evaluation was performed under the following conditions. All evaluations were performed in a dry state. (1) Tensile strength and elongation: According to ASTM D638, a 3.2 mm-thick No. 1 test piece was used at a pulling rate of 5 mm / min. (2) Flexural strength and flexural modulus: A three-point bending test was performed using a 3.2 mm-thick strip test piece according to ASTM D790. (3) Impact strength: 3.2 mm thick strip according to ASTM D256. The test pieces were notched by post-processing and evaluated with an Izod impact tester.

(Evaluation of Formability) (4) Flow Length: Using a spiral mold for measuring the flow length of a rod having a width of 12.5 mm and a thickness of 1 mm, the flow length was measured at an injection pressure of 50 MPa with an SG75 injection molding machine manufactured by Sumitomo Heavy Industries. did.

(Evaluation of Welding Strength) (5) Injection Welding Strength: Tension of a test piece having the shape shown in FIGS. 1 to 3 formed by the DRI method using the composition obtained in the present invention under the following conditions. The strength was measured. The tensile conditions were a tensile speed of 5 mm / sec and a distance between chucks of 25 mm. Molding machine: Nikko N140BII Resin temperature: See Tables 1 and 2. Mold temperature: 80 ° C Holding pressure: 20 MPa Injection time: 1 sec Cooling time: 20 sec

Reference Example 1 (Polyamide A) In a 70 liter autoclave, 20 kg of ε-caprolactam and 0.1 ml of water were added as polymerization monomers.
5 kg, meta-xylylenediamine at 1/290 (eq /
mol lactam), the inside of the tank was replaced with nitrogen, and then heated to 100 ° C. and stirred so that the inside of the tank was uniform. Next, after polymerization was performed in the tank at 260 ° C. and 1.7 MPa, unreacted monomers were extracted from the obtained polymer in hot water at 100 ° C. to obtain a sample. The resulting polyamide 6 had a relative viscosity of 2.50 and a terminal amino group concentration of 90 meq / k.
g.

Reference Example 2 (Polyamide B) A polyamide 6 was obtained in the same manner as in Reference Example 1, except that 1/350 (eq / mol lactam) was used as meta-xylylenediamine. The terminal amino group concentration of the obtained polyamide 6 is 60 meq / kg.
Met.

Reference Example 3 (Polyamide C) A polyamide 6 was obtained in the same manner as in Reference Example 1, except that meta-xylylenediamine was changed to 1/200 (eq / mol lactam). Terminal amino group concentration of the obtained polyamide 6: 110 meq / k
g.

Reference Example 4 (Polyamide D) Polyamide 6 was obtained in the same manner as in Reference Example 1, except that meta-xylylenediamine was changed to 1/400 (eq / mol lactam). Terminal amino group concentration of obtained polyamide 6 50 meq / kg
Met.

Example 1 Polyamide 6 (polyamide A) having a relative viscosity of 2.50 and a terminal amino group concentration of 90 meq.
Glass fiber (glass fiber diameter 11 μm, glass fiber cut length 3 mm, manufactured by Nippon Electric Glass Co., Ltd.)
Weight part and a barrel temperature of 270 ° C.
The mixture was kneaded by a twin-screw extruder with a vent. A predetermined amount of the glass fiber was supplied in the middle of the extruder to prepare a target reinforced polyamide resin composition pellet. Next, the obtained pellet is dried at 110 ° C. under a reduced pressure of 10 torr for 24 hours, and then injection molded at a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C. to form a tensile test specimen, a bending test specimen, and an impact test specimen conforming to ASTM. And evaluated the liquidity. Further, the tensile strength of the test piece formed by the DRI method was measured. Table 1 shows the obtained results.

Examples 2 to 3 A reinforced polyamide resin composition was prepared in the same manner as in Example 1 except that the proportion of the glass fibers was changed as shown in Table 1.
The physical properties were evaluated. The results obtained are shown in Table 1.

Example 4 A reinforced polyamide resin composition was prepared in the same manner as in Example 1 except that polyamide 6 (polyamide B) having a terminal amino group concentration of 60 meq / kg of polymer was used, and its physical properties were evaluated. did. The results obtained are shown in Table 1.

Example 5 A polyamide 6 (polyamide C) having a terminal amino group concentration of 110 meq / kg of polymer was used, except that
A reinforced polyamide resin composition was prepared in the same manner as in Example 1,
The physical properties were evaluated. The results obtained are shown in Table 1.

Example 6 A reinforced polyamide resin composition was prepared in the same manner as in Example 1 except that talc (talc cup manufactured by Tsuchiya Kaolin Kogyo KK) was supplied in a proportion of 45 parts by weight instead of glass fiber. Physical properties were evaluated. The results obtained are shown in Table 1.

Comparative Example 1 A reinforced polyamide resin composition was prepared in the same manner as in Example 1 except that polyamide 6 (polyamide D) having a terminal amino group concentration of 50 meq / kg of polymer was used, and its physical properties were evaluated. did. The results obtained are shown in Table 1.

[0038]

[Table 1]

From these results, it can be seen that the composition using (A) a polyamide having an amino terminal group concentration of 60 milliequivalents or more per 1 kg of the polymer exhibits an excellent effect of improving the welding strength, and the effect is various. It is effective for crystalline polyamide resin.

[0040]

The reinforced polyamide resin composition of the present invention comprises:
It has high welding strength without impairing the intrinsic properties of the crystalline polyamide resin. For this reason, it can be used for a large molded product or a component having a complicated shape without depending on a special molding machine or a post-processing method.

[0041]

[Brief description of the drawings]

FIG. 1 shows a front view of an example of a test piece.
(The unit of the numerical value is mm)

FIG. 2 shows a side view of an example of a test piece.
(The unit of the numerical value is mm)

FIG. 3 shows a state diagram of a test piece formed by the DRI method.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F072 AA02 AA05 AA08 AB09 AD44 AF06 AK15 AL02 AL11 4J002 CL011 DA016 DE186 DE236 DJ006 DJ016 DJ036 DJ046 DJ056 DL006 FA016 FA046 FA066 FA086 FD016 GN00 GQ00

Claims (3)

[Claims] (A) The amino terminal group concentration of a polymer is 1 kg.
Crystalline polyamide resin 1 having a content of 60 milliequivalents or more per unit
00 parts by weight (B) A reinforced polyamide resin composition for molding excellent in strength of a welded portion comprising 5 to 200 parts by weight of an inorganic filler. 2. The reinforced polyamide resin composition for molding according to claim 1, wherein the crystalline polyamide resin comprises lactam or aminocarboxylic acid. 3. The method according to claim 1, wherein the inorganic filler is glass fiber.
3. The reinforced polyamide resin composition for molding according to any one of 2), wherein the reinforced polyamide resin composition has excellent strength at a welded portion.