KR20180126980A - Polyamide resin composition and molded artice manufactured therefrom - Google Patents

Abstract

The present invention relates to a polyamide resin composition used for automotive fasteners, and a molded product using the same. The polyamide resin composition comprises: a polyamide resin; 5-20 parts by weight of an EBA-based shock-resistant agent, and 5-10 parts by weight of an EAA-based shock-resistant agent, with respect to 100 parts by weight of the polyamide resin; and 0.1-1.0 parts by weight of a release agent, wherein the polyamide resin is a mixture containing Polyamide6 and Polyamide66 in a weight ratio of 4 : 6 to 6 : 4. The polyamide resin composition of the present invention may be used to manufacture molded products having excellent flexibility, strength, shock resistance, insertion force, and pull-off force; effective for SINK improvement and mold release; and having excellent moldability and GAS stability. In particular, the molded products using the polyamide resin composition of the present invention may be used in vehicle components, such as automotive fasteners, and components used in the electrical and electronics fields.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition,

The present invention relates to a polyamide resin composition used for automobile fasteners and molded articles thereof.

Due to the recent advancement of automobile interior and exterior materials, the design and form of convenience parts and auxiliary parts such as advanced parts and electric parts have been diversified. Especially, plastic fasteners .

Plastic fasteners for automobiles are used in various forms by designing vehicles and upgrading electric parts and so on, and they are required to have excellent elasticity and resilience because they are required to have an insertion force and a detachment force when the vehicle body is engaged. If it is excellent, the connection can be made smoothly. Such plastic fasteners for automobiles are liable to cause problems such as generation of GAS, defective moldings, and molding defects due to the small size and thin flange when injection molded, which requires caution in production.

Fasteners used in automotive interiors are generally made of nylon 6, nylon 66 or copolyamide.

In general, the polyamide resin composition is superior in heat resistance and mechanical properties to general-purpose resins such as olefin resins, and has chemical properties such as oil resistance and chemical resistance, electrical properties, friction and abrasion characteristics, A variety of additives can be added to obtain a composition having various functions, thereby being used in automobile industry, electric, electronic, and general industrial parts. In order to be applied as a material for a fastener, such a polyamide resin is required to have an appropriate flexibility and an improved strength, and it is desired to provide an appropriate flexibility through a method of adding a plasticizer and a method of adding an impactor, . ≪ / RTI >

However, if only additives such as plasticizers and impact modifiers are used, there may be problems such as surface defects due to gas generation during injection molding, and occurrence of SINK due to structural problems in some specific types of fasteners.

Korean Patent Laid-Open Publication No. 1999-0029902, U.S. Patent Nos. 6,348,563, 6,384,115, 6,239,216 and 5,032,633 disclose attempts to improve the flexibility of a polyamide resin by adding a plasticizer of various derivatives, Low productivity, and degraded impact properties.

Korean Patent Laid-Open Publication No. 2002-0046389 discloses that ethylene propylene rubber (impact resistant agent) is added to a polypropylene resin to improve flexibility and to improve heat resistance, which is a disadvantage of a general-purpose resin, with an excessive amount of talc. However, There is a problem that the impact strength and elongation are lowered and the density due to excessive talc rises and the weight of the molded article increases.

Korean Patent Laid-Open Publication No. 1990-0018273 discloses a rubber composition comprising an EPDM rubber modified with a rubber or maleic anhydride grafted with a styrene-acrylonitrile copolymer on an ethylene propylene rubber, There is a problem in that the crystallization speed is slow and the productivity is low.

As can be seen from the prior art, the use of a plasticizer results in a drop in impact strength and a decrease in productivity due to the generation of GAS. When a shockproofing agent is mixed and used, adequate flexibility and impact strength to be used as a material for a fastener are satisfied, Moldability is reduced due to structural problems in the form. Further, in some materials to which an ion-impact-type impactor is applied, poor metering is caused in injection molding.

Therefore, it is required to develop a material which can solve the SINK problem which can be caused by structural problems while satisfying the impact resistance, the insertion force and the detachment force, and which can secure the metering stability and the GAS stability.

Accordingly, the present invention provides a polyamide resin composition excellent in flexibility, strength, impact resistance, insertion force and releasing force, effective for improving SINK, effective for mold release, and excellent in metering stability and GAS stability. Further, a polyamide resin molded article comprising the polyamide resin composition is provided.

Accordingly, the present invention provides, as a first preferred embodiment, a polyamide resin; Based on 100 parts by weight of the polyamide resin, 5 to 20 parts by weight of an EBA type impact resistant agent, 5 to 10 parts by weight of an EAA type impact resistant agent, And 0.1 to 1.0 part by weight of a release agent, wherein the polyamide resin is a mixture of polyamide 6 and polyamide 66 in a weight ratio of 4: 6 to 6: 4.

The polyamide resin according to the first embodiment may have a relative viscosity of 2.5 to 3.5.

The polyamide resin according to the first embodiment may have a weight average molecular weight of 5,000 to 20,000 g / mol.

The EBA based impact resistant agent according to the first embodiment is obtained by adding 0.5 to 5 parts by weight of at least one of?,? - unsaturated carboxylic acid,?,? - unsaturated anhydride and derivatives thereof to 100 parts by weight of an ethylene butyl acrylate copolymer And at least one compound selected from the group consisting of grafted compounds.

The EAA-based impact resistant agent according to the first embodiment is obtained by adding 0.5 to 5 parts by weight of at least one of?,? - unsaturated carboxylic acid,?,? - unsaturated anhydride and derivatives thereof to 100 parts by weight of an ethylene acrylic acid copolymer Or a mixture thereof.

The release agent according to the first embodiment may be one or more selected from the group consisting of ethylene bistostearamide, oleamide, erucamide, and stearamide.

Further, as a second preferred embodiment of the present invention, a polyamide resin molded article comprising the polyamide resin composition can be provided.

The insertion force of the molded article according to the second embodiment may be 2 kgf / cm ² or more, the separation force may be 20 kgf / cm ² or more, and the impact resistance may be 7 kgf / cm ² or more.

INDUSTRIAL APPLICABILITY The polyamide resin composition of the present invention can produce polyamide resin molded articles having excellent flexibility, strength, impact resistance, insertion force and releasing force, effective for improvement of SINK and mold releasing property, and excellent in metering stability and GAS stability.

Particularly, the polyamide resin molded article of the present invention can be used in automotive electric parts such as fasteners for automobiles, and parts in the electric and electronic fields.

According to one aspect of the present invention, there is provided a polyamide resin composition comprising: a polyamide resin; Based on 100 parts by weight of the polyamide resin, 5 to 20 parts by weight of an EBA type impact resistant agent, 5 to 10 parts by weight of an EAA type impact resistant agent, And 0.1 to 1.0 part by weight of a release agent, wherein the polyamide resin is a mixture of polyamide 6 and polyamide 66 in a weight ratio of 4: 6 to 6: 4.

Hereinafter, the present invention will be described in more detail.

[Polyamide resin]

The polyamide resin according to the present invention includes a mixture of polyamide 6 and polyamide 66 resin, and it is preferable that the blend weight ratio of polyamide 6 and polyamide 66 resin is 4: 6 to 6: 4. If the weight ratio of the polyamide 6 resin is less than 40% by weight based on the polyamide resin, the flexibility of the fastener may be too high to weaken the releasing force when the polyamide 6 resin is attached. If the polyamide resin is used in an amount exceeding 60% by weight, the flexibility may be too low and the insertion force may become insufficient.

As a preferable example, the polyamide resin composition of the present invention uses a resin composed of 50 wt% of each of a polyamide 6 resin and a polyamide 66 resin

The relative viscosity of the polyamide resin may be 2.5 to 3.5, wherein the relative viscosity is measured using a ubbelohde viscometer. The conditions are 20 ° C, 100 ml of 96% sulfuric acid, And the relative viscosity of the solution containing 1 g of the polyamide resin was measured.

When the relative viscosity of the polyamide resin is less than 2.5, rigidity, impact strength and heat resistance may be lowered. When the polyamide resin is more than 3.5, excessive friction heat is generated between the screw and the resin in the molding machine to decompose the resin, So that it is difficult to perform injection molding by generating a crowd in the molding machine and the mold.

The polyamide resin preferably has a weight average molecular weight of 5,000 to 20,000 g / mol. The weight average molecular weight is measured by a HPLC analyzer. Mechanical strength may be weak if the weight average molecular weight is less than 5,000 g / mol, and melt processability may be deteriorated when the weight average molecular weight is more than 20,000 g / mol.

The weight average molecular weight is measured by the following method:

1. Analytical instrument: Agilent Technologies 1200Series

2. Stationary phase: u Stragel 103 104 105 (three columns connected in series)

3. Mobile phase: Chlorofrom / OCP standard solvent = 4/1, 1.0 ml / min

4. Temperature: 40 캜 (stationary phase column and RI detector)

5. Reference substance: Polystyrene

6. Injection amount: 20 μl

7. Detector: Agilent G1316A RI, 40 DEG C

8. Analysis time: 30 minutes

On the other hand, the polyamide resin of the present invention can be used in the form of a chip for drying polyamide resin composition and dried in a dehumidifying dryer.

[ EBA system Impact Resistant ]

The EBA based impact resistant agent used in the present invention is effective in imparting impact resistance, insertion force, release force and the like, and its content may be 5 to 20 parts by weight based on 100 parts by weight of the polyamide resin. When the content is less than 5 parts by weight The effect of the impact resistance characteristic may not be sufficient. If the amount exceeds 20 parts by weight, the detachment force may be lowered and it may be difficult to use as an intended use.

The EBA impact-resistant agent includes a compound in which 0.5 to 5 parts by weight of at least one of?,? - unsaturated carboxylic acid,?,? - unsaturated anhydride and derivatives thereof is grafted to 100 parts by weight of an ethylene butyl acrylate copolymer do.

When the content is less than 0.5 parts by weight, compatibility with the polyamide resin is poor. If the content is more than 5 parts by weight, high viscosity increases and kneading becomes difficult and the quality of the outer surface of the molded article becomes poor.

The grafting process is usually carried out in the presence of a solvent or peroxide in the presence of a molten olefin.

[ EAA system Impact Resistant ]

The EAA-based impact resistant agent used in the present invention is effective for improving the SINK and mold releasability, and its content may be 5 to 10 parts by weight based on 100 parts by weight of the polyamide resin. When the amount is less than 5 parts by weight, If the amount is more than 10 parts by weight, the detachment force may be lowered and it may be difficult to use as an intended use.

The EAA-based impact resistant agent includes a compound in which 0.5 to 5 parts by weight of at least one of?,? - unsaturated carboxylic acid,?,? - unsaturated anhydride and derivatives thereof is grafted onto 100 parts by weight of an ethylene acrylic acid copolymer.

When the content is less than 0.5 parts by weight, compatibility with the polyamide resin is poor. If the content is more than 5 parts by weight, high viscosity increases and kneading becomes difficult and the quality of the outer surface of the molded article becomes poor.

The grafting process is usually carried out in the presence of a solvent or peroxide in the presence of a molten olefin.

[ Release agent ]

The release agent used in the present invention is effective in imparting smooth releasability in a mold due to its small size and large number during injection molding of a fastener or button, and its content is 0.1 to 1.0 part by weight based on 100 parts by weight of the polyamide resin desirable.

If the content is less than 0.1 part by weight, the effect of the release agent may be insufficient. If the content is more than 1.0 part by weight, the effect of improving the releasability is insignificant and a problem due to generation of GAS may occur.

The release agent may be at least one selected from the group consisting of ethylene bisstearamide, oleamide, erucamide and stearamide chemicals.

The polyamide resin composition according to the present invention may also contain other additives such as an antioxidant, a heat stabilizer, a light stabilizer, a slip agent, a pigment (specifically, carbon black, etc.), an antioxidant such as a polyamide resin, an EBA impact- A coupling agent, and the like.

The method for producing the polyamide resin composition according to the present invention is not particularly limited as long as it is a general method for producing a polyamide resin composition used in the art.

In the present invention, a method using a twin screw extruder can be presented as an example of a method for producing a polyamide resin composition.

[Example]

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for describing the present invention in more detail and that the scope of the present invention is not limited by these embodiments.

Example  1 to 9 and Comparative Example  1 to 8

(KOPA KN111, relative viscosity of 2.7), polyamide 66 (Kolon Plastics, trade name KOPA KN3311, relative viscosity of 2.7), EBA type shockproofing agent (DUPONT) (Product name: FUSABOND A560), an EAA-based impacting agent (1.2 parts by weight of maleic anhydride was blended with 100 parts by weight of an ethylene acrylic acid copolymer) and a release agent (Akzo Chemicals, trade name: Interstabg-8257) , And the kneaded melt was cooled while passing through a water bath and cut to prepare a polyamide resin composition in the form of a pellet.

division Content (parts by weight) Polyamide
(Polyamide 6: polyamide 66) EBA type shockproofing agent EAA Impact Resistant Release agent Example 1 100 (50:50) 10 7 0.2 Example 2 100 (40:60) 10 7 0.2 Example 3 100 (60:40) 10 7 0.2 Example 4 100 (50:50) 5 7 0.2 Example 5 100 (50:50) 20 7 0.2 Example 6 100 (50:50) 10 5 0.2 Example 7 100 (50:50) 10 10 0.2 Example 8 100 (50:50) 10 7 0.1 Example 9 100 (50:50) 10 7 1.0 Comparative Example 1 100 (39:61) 10 7 0.2 Comparative Example 2 100 (61:39) 10 7 0.2 Comparative Example 3 100 (50:50) 4 7 0.2 Comparative Example 4 100 (50:50) 21 7 0.2 Comparative Example 5 100 (50:50) 10 4 0.2 Comparative Example 6 100 (50:50) 10 11 0.2 Comparative Example 7 100 (50:50) 10 5 0.09 Comparative Example 8 100 (50:50) 10 5 1.1

The pellets prepared in Examples and Comparative Examples were dried at a temperature of 85 캜 for 6 hours by using a dehumidifying dryer, and then a fastener specimen of a polyamide resin composition was prepared using a heated screw extruder.

 Sink, surface (appearance) were measured by the following methods, and the results are shown in Table 2.

(1) Insertion force

USER The fastener specimen was manufactured using the fastener mold that was applied, and it was measured according to ESER1600-00, a fastener evaluation method for HARNESS by USER.

(2) Disengagement force

USER The fastener specimen was manufactured by using the fastener mold which was applied, and it was measured by ESER1600-00, fastener evaluation method for HARNESS by USER.

(3) Impact resistance

Izod Notched impact strength was measured after 1/4-inch specimen was manufactured according to ASTM D256, and defective and good products were judged according to whether the SPEC was passed or not.

(4) Dissimilarity

USER It was judged by dividing the mold releasing property into two stages of visual inspection and insufficient / goodness when the fastener specimen was manufactured using the fastener mold under application.

(5) SINK

 The fastener specimen was manufactured using the fastener mold under USER application, and the degree of SINK of the structural SINK occurrence site was judged by visual inspection and classified into two stages of insufficient / good.

(6) Surface (appearance)

USER The fastener mold was used to fabricate the fastener specimen, and the degree of GAS occurrence at the easy GAS deposition sites such as the flange part was judged by visual inspection and classified into two stages, insufficient / good.

division Fastening force (kgf / cm ² ) Impact resistance
(kgf / cm ² ) Dysplasia SINK Surface (Appearance) Insertion force Release force Example 1 2.52 25.33 12.51 Good Good Good Example 2 2.77 21.02 13.17 Good Good Good Example 3 2.04 26.75 12.94 Good Good Good Example 4 2.43 25.43 7.68 Good Good Good Example 5 2.12 20.91 21.88 Good Good Good Example 6 2.39 25.75 11.82 Good Good Good Example 7 2.11 21.42 18.71 Good Good Good Example 8 2.60 25.72 12.85 Good Good Good Example 9 2.51 24.90 13.85 Good Good Good Comparative Example 1 3.05 19.83 13.22 Good Good Good Comparative Example 2 1.92 28.45 13.03 Good Good Good Comparative Example 3 2.38 26.52 5.75 Good Good Good Comparative Example 4 2.03 19.51 23.06 Good Good Good Comparative Example 5 2.31 26.07 9.34 Inadequate Inadequate Good Comparative Example 6 2.06 18.13 19.71 Good Good Good Comparative Example 7 2.58 25.42 13.11 Inadequate Good Good Comparative Example 8 2.49 24.95 13.69 Good Good Inadequate

As a result of measurement of physical properties, as shown in Table 2, the polyamide resin was used as a base material in Examples 1 to 9 according to the present invention, and the EBA type impact resistant agent, the EAA type impact resistant agent, Excellent insertion force, release force, impact resistance, releasability, SINK and surface (appearance) characteristics can be secured.

On the other hand, as can be seen in Comparative Examples 1 and 2, if the ratio of the polyamide is biased, it can be confirmed that the insertion force or the separation force does not reach the required level.

In Comparative Examples 3 to 4, when the content of the EBA-based impact-resistant agent is small, the required impact resistance is not satisfied, and when it is added in an excessive amount, the detachment force is decreased.

In Comparative Examples 5 to 6, if the content of the EAA-based impact resistant agent is small, the releasing property and the SINK property are deteriorated, and the detachment force is deteriorated when the excess amount is added.

In Comparative Examples 7 to 8, when the amount of the releasing agent to be added is small, the releasability is decreased, and when excessive amount is added, appearance defects such as surface GAS occur.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (8)

Polyamide resins;
Based on 100 parts by weight of the polyamide resin, 5 to 20 parts by weight of an EBA type impact resistant agent, 5 to 10 parts by weight of an EAA type impact resistant agent, And 0.1 to 1.0 part by weight of a release agent,
Wherein the polyamide resin is a mixture of polyamide 6 and polyamide 66 in a weight ratio of 4: 6 to 6: 4. The polyamide resin composition according to claim 1, wherein the polyamide resin has a relative viscosity of 2.5 to 3.5. The polyamide resin composition according to claim 1, wherein the polyamide resin has a weight average molecular weight of 5,000 to 20,000 g / mol. The method according to claim 1,
The EBA-based impact-resistant agent is composed of a compound obtained by grafting 0.5 to 5 parts by weight of at least one of?,? - unsaturated carboxylic acid,?,? - unsaturated anhydride and derivatives thereof in 100 parts by weight of an ethylene butyl acrylate copolymer Lt; RTI ID = 0.0 > 1, < / RTI > The method according to claim 1,
The EAA-based impact-resistant agent is a compound composed of a compound obtained by grafting 0.5 to 5 parts by weight of at least one of?,? - unsaturated carboxylic acid,?,? - unsaturated anhydride and derivatives thereof in 100 parts by weight of an ethylene acrylic acid copolymer Wherein the polyamide resin composition is a polyamide resin composition. The method according to claim 1,
Wherein the release agent is at least one selected from the group consisting of ethylenebisstearamide, oleamide, erucamide and stearamide compounds. A polyamide resin molded article comprising the polyamide resin composition according to any one of claims 1 to 6. The polyamide resin molded article according to claim 7, wherein an insertion force of the molded article is 2 kgf / cm ² or more, a separation force is 20 kgf / cm ² or more, and an impact resistance is 7 kgf / cm ² or more.