KR102275119B1 - Polyamide resin composition and molded artice manufactured therefrom - Google Patents

Abstract

The present invention relates to a polyamide resin composition used for automobile fasteners and molded articles thereof.
The polyamide resin composition may include a polyamide resin; Based on 100 parts by weight of the polyamide resin, 5 to 20 parts by weight of an EBA-based impact resistant agent, 5 to 10 parts by weight of an EAA-based impact resistant agent; and 0.1 to 1.0 parts by weight of a release agent, and the polyamide resin is characterized in that polyamide 6 and polyamide 66 are mixed in a weight ratio of 4:6 to 6:4.
The polyamide resin composition of the present invention has excellent flexibility, strength, impact resistance, insertion force and release force, is effective in improving SINK and mold releasability, and can produce a polyamide resin molded article having excellent weighing stability and GAS stability.
In particular, the polyamide resin molded article of the present invention can be used for automotive electronic parts such as automotive fasteners and parts in the electric and electronic field.

Description

Polyamide resin composition and molded article thereof {POLYAMIDE RESIN COMPOSITION AND MOLDED ARTICE MANUFACTURED THEREFROM}

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

Due to the recent advancement of interior and exterior materials for automobiles, the design and shape of convenience parts and ancillary parts such as high-end parts and electronic parts are diversifying. .

Plastic fasteners for vehicles are used in various forms in automobiles due to the design of vehicles and the advancement of electronic components. When this is excellent, the fastening can be performed smoothly. When these plastic fasteners for vehicles are injection molded, there is a high possibility that problems such as gas generation, mold release defects, and molding defects occur due to their small size and thin flanges, so caution is required during production.

Fasteners used for interior and exterior of automobiles are generally made of nylon 6, nylon 66, or copolyamide.

In general, polyamide resin compositions have superior heat resistance and mechanical properties compared to general-purpose resins such as olefinic resins, and have excellent electrical properties, friction and wear properties as well as chemical properties such as oil resistance and chemical resistance, and provide various properties By reinforcing various additives for this, a composition with various functions can be obtained, so it is used in the automobile industry and parts of the electric, electronic, and general industries. In order to be applied as a material for fasteners, the polyamide resin needs to be improved in strength with appropriate flexibility, and it is given appropriate flexibility through a method of adding a plasticizer and an impact resistance agent, and flexural modulus and impact strength. can have

However, if only the above additives for plasticizer and impact resistance are used, problems such as poor surface condition due to gas generation during injection molding and SINK generation due to structural problems in some specific types of fasteners may occur.

Korean Patent Publication No. 1999-0029902, US Patent Nos. 6,348,563, 6,384,115, 6,239,216 and 5,032,633 add plasticizers of various derivatives to improve the flexibility of polyamide resins, but There are limits in terms of low productivity and low impact characteristics.

In Korea Patent Publication No. 2002-0046389, ethylene propylene rubber (impact resistant agent) was added to polypropylene resin to improve flexibility and to improve heat resistance, which is a disadvantage of general-purpose resin by excessive talc filling, but compared to polyamide resin, There is a problem in that the impact strength and elongation are lowered, and the density increases due to excessive talc, which increases the weight of the molded article.

Korean Patent Laid-Open Publication No. 1990-0018273 discloses an impact-resistance rubber composed of an interpolymer mixed with a polyamide resin, grafted with a styrene-acrylonitrile copolymer on ethylene propylene rubber, or an EPDM rubber modified with maleic anhydride. There is a known technology that uses zero to improve flexibility and impact properties, but there is a problem in that the crystallization rate is slowed down and productivity is lowered.

As can be seen in the prior art, the use of a plasticizer causes a decrease in impact strength and a decrease in productivity due to the generation of gas. Formability is poor due to structural problems in shape. In addition, in the case of materials to which some ion-bonding type impact-resistance agents are applied, poor metering performance during injection molding has occurred.

Therefore, it is required to develop a material that satisfies impact resistance, insertion force, detachment force, etc. while resolving the SINK problem that may be caused by structural problems and securing weighing stability and gas stability.

Accordingly, the present invention provides a polyamide resin composition having excellent flexibility, strength, impact resistance, insertion force and release force, effective for SINK improvement and mold release property, and excellent weighing stability and gas stability. In addition, there is provided a polyamide resin molded article comprising the polyamide resin composition.

Accordingly, the present invention 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-based impact resistant agent, 5 to 10 parts by weight of an EAA-based impact resistant agent; and 0.1 to 1.0 parts 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 0.5 to 5 parts by weight of at least one of α,β-unsaturated carboxylic acid, α,β-unsaturated anhydride and derivatives thereof to 100 parts by weight of the ethylene butyl acrylate copolymer It may be at least one selected from the group consisting of grafted compounds.

The EAA-based impact resistance agent according to the first embodiment is 0.5 to 5 parts by weight of at least one of α,β-unsaturated carboxylic acid, α,β-unsaturated anhydride and derivatives thereof to 100 parts by weight of the ethylene acrylic acid copolymer. It may be at least one selected from the group consisting of tidated compounds.

The mold release agent according to the first embodiment may be at least one selected from the group consisting of ethylenebisstearamide, oleamide, erucamide, and stearamide compounds.

In addition, as a second preferred embodiment, the present invention may provide a polyamide resin molded article including the polyamide resin composition.

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

The polyamide resin composition of the present invention has excellent flexibility, strength, impact resistance, insertion force and release force, is effective in improving SINK and mold releasability, and can produce a polyamide resin molded article having excellent weighing stability and GAS stability.

In particular, the polyamide resin molded article of the present invention can be used for automotive electronic parts such as automotive fasteners and parts in the electric and electronic field.

According to an aspect of the present invention, polyamide resin; Based on 100 parts by weight of the polyamide resin, 5 to 20 parts by weight of an EBA-based impact resistant agent, 5 to 10 parts by weight of an EAA-based impact resistant agent; and 0.1 to 1.0 parts by weight of a release agent, wherein the polyamide resin may provide a polyamide resin composition in which polyamide 6 and polyamide 66 are mixed 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 the mixing weight ratio of polyamide 6 and polyamide 66 resin is preferably 4:6 to 6:4. When the weight ratio of the polyamide 6 resin is less than 40% by weight relative to the polyamide resin, the flexibility for fasteners is too high, so the detachment force may be weakened during installation, and the weight ratio of the polyamide 6 resin is If it is used in an amount exceeding 60% by weight based on the polyamide resin, the flexibility may be too low and the insertion force may be insufficient.

As a preferred example, the polyamide resin composition of the present invention used a resin composed of 50% by weight of each of polyamide 6 resin and polyamide 66 resin.

The polyamide resin may have a relative viscosity of 2.5 to 3.5, wherein the relative viscosity is measured using an ubbelohde viscometer and the conditions are 20°C, 96% sulfuric acid 100 ml, 20° C., 96% sulfuric acid 100 ml It is the value measured by the relative viscosity of the solution to which 1 g of polyamide resin was added.

If the relative viscosity of the polyamide resin is less than 2.5, rigidity, impact strength, and heat resistance may be reduced, and when it exceeds 3.5, excessive frictional heat between the screw and the resin in the molding machine is generated to decompose the resin, or high pressure during molding This is necessary, which may cause strain on the molding machine and the mold, making injection molding difficult.

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 through an HPLC analyzer. If the weight average molecular weight is less than 5,000 g/mol, mechanical strength may be weak, and if it exceeds 20,000 g/mol, melt processability may be deteriorated.

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

1. Analytical Instruments: Agilent Technologies 1200Series

2. Stationary phase: u Stragel 103 104 105 (analyzed by connecting 3 columns in series)

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

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

5. Reference material: Polystyrene

6. Injection volume: 20 μl

7. Detector: Agilent G1316A RI, 40℃

8. Analysis time: 30 minutes

On the other hand, the polyamide resin of the present invention can be used after drying in a dehumidifying dryer in the form of chips for the production of the polyamide resin composition.

[ EBA system impact resistant ]

The EBA-based impact resistance agent used in the present invention is effective in imparting impact resistance, insertion force, release force, etc., and its content may be 5 to 20 parts by weight based on 100 parts by weight of the polyamide resin, and if the content is less than 5 parts by weight The impact resistance property effect may not be sufficient, and if it exceeds 20 parts by weight, it may be difficult to use it for the intended purpose because the release force is lowered.

The EBA-based impact resistant agent contains 0.5 to 5 parts by weight of a compound grafted with at least one of α,β-unsaturated carboxylic acid, α,β-unsaturated anhydride, and derivatives thereof to 100 parts by weight of ethylene butyl acrylate copolymer do.

When the content is less than 0.5 parts by weight, compatibility with the polyamide resin is deteriorated, and when it exceeds 5 parts by weight, it is difficult to knead with a high viscosity increase, and the appearance surface quality of the molded article is poor.

The grafting method is usually carried out on molten olefins in a solvent phase or in the presence of a peroxide.

[ EAA system impact resistant ]

The EAA-based impact resistance agent used in the present invention is effective in improving SINK and mold release properties, and its content may be 5 to 10 parts by weight based on 100 parts by weight of the polyamide resin, and if the content is less than 5 parts by weight, the release property and SINK improvement effect may not be enough, and if it exceeds 10 parts by weight, the detachment force may be lowered and it may be difficult to use for the intended purpose.

The EAA-based impact resistant agent includes a compound grafted with 0.5 to 5 parts by weight of at least one of α,β-unsaturated carboxylic acid, α,β-unsaturated anhydride and derivatives thereof to 100 parts by weight of the ethylene acrylic acid copolymer.

When the content is less than 0.5 parts by weight, compatibility with the polyamide resin is deteriorated, and when it exceeds 5 parts by weight, it is difficult to knead with a high viscosity increase, and the appearance surface quality of the molded article is poor.

The grafting method is usually carried out on molten olefins in a solvent phase or in the presence of a peroxide.

[ release agent ]

The release agent used in the present invention is effective in providing smooth release properties in the mold due to its small size and large number during injection molding of fasteners or buttons, and its content is contained in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the polyamide resin. desirable.

If the content is less than 0.1 parts by weight, the effect of the release agent may be insufficient, and if it exceeds 1.0 parts by weight, the improvement effect of the release property is no longer insignificant, and a problem may occur due to the generation of GAS.

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

The polyamide resin composition according to the present invention includes, in addition to the above-described polyamide resin, EBA-based impact-resistance agent, EAA-based impact-resistance agent and mold release agent, antioxidant, heat stabilizer, light stabilizer, slip agent, pigment (specifically, carbon black, etc.), charge It may further include one or more selected from the group consisting of an inhibitor, a coupling agent, and the like.

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

In the present invention, as an example of a method for preparing a polyamide resin composition, a method using a twin-screw extruder may be provided.

[Example]

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention in more detail, and it will be apparent to those of ordinary skill in the art to which the present invention pertains that the scope of the present invention is not limited by these examples.

Example 1 to 9 and comparative example 1 to 8

According to the composition as shown in Table 1, polyamide 6 (Kolon Plastics, trade name KOPA KN111, relative viscosity 2.7), polyamide 66 (Kolon Plastics, trade name KOPA KN3311 , relative viscosity 2.7), EBA-based impact resistance agent (DUPONT) , trade name FUSABOND A560), EAA-based impact resistant agent (prepared by grafting 1.2 parts by weight of maleic anhydride to 100 parts by weight of ethylene acrylic acid copolymer), and release agent (Akzo Chemicals, trade name Interstabg-8257) were melt-kneaded in an extruder , the kneaded melt was cooled while passing through a water bath and cut to prepare a polyamide resin composition in the form of pellets.

division Content by component (parts by weight) polyamide
(Polyamide 6: Polyamide 66) EBA-based impact-resistance agent EAA type 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

After drying the pellets prepared in Examples and Comparative Examples for 6 hours using a dehumidifying dryer at a temperature of 85° C., using a heated screw-type injection machine, fastener specimens of the polyamide resin composition were prepared.

Separation force, insertion force, impact strength, releasability, SINK, and surface (appearance) were measured in the following way, and the results are shown in Table 2.

(1) Insertion force

After making fastener specimens using the fastener mold that is being applied to the user, it was measured according to ES91600-00, a fastener evaluation method for USER's HARNESS, and defective and good products were judged according to whether the SPEC was passed or not.

(2) Breakaway force

After making fastener specimens using the fastener molds applied by the user, measurements were made according to ES91600-00, a fastener evaluation method for HARNESS by the user, and defective or good products were judged according to whether the SPEC was passed or not.

(3) Impact resistance

Izod notched impact strength was measured after producing a 1/4 inch specimen in accordance with ASTM D256, and defective or good products were judged according to whether the SPEC passed or not.

(4) releasability

When manufacturing fastener specimens using a fastener mold that is being applied to the user, the mold release property was visually determined and judged by dividing it into two stages of poor/good.

(5) SINK

Using the fastener mold applied by the user, the fastener specimen was manufactured, and the SINK degree of the structural SINK occurrence site was visually determined, and then divided into two stages, poor/good, and judged.

(6)Surface (appearance)

Using a fastener mold applied by the user, a fastener specimen was manufactured, and the degree of gas generation in areas where gas deposition is easy, such as the flange part, was visually judged, and then divided into two stages: poor/good.

division Tightening force (kgf/cm ² ) impact resistance
(kgf/cm ² ) atypia SINK surface (appearance) insertion force breakaway 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 the measurement of physical properties, as shown in Table 2, based on the polyamide resin through Examples 1 to 9 according to the present invention, EBA-based impact-resistance agent, EAA-based impact-resistance agent, and release agent were included in the optimal range, Excellent insertion force, detachment 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, when the ratio of polyamide is biased, it can be confirmed that the insertion force or release force does not reach the required level.

In Comparative Examples 3 to 4, when the content of the EBA-based impact agent is small, the required impact resistance is not satisfied, and it can be confirmed that the release force is lowered when an excessive amount is added.

In Comparative Examples 5 to 6, it can be seen that when the content of the EAA-based impact agent is small, the releasability and SINK properties deteriorate, and the release force is lowered when an excessive amount is added.

In Comparative Examples 7 to 8, it can be seen that when the amount of the release agent added is small, the release property is deteriorated, and when an excessive amount is added, appearance defects such as surface gas occur.

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (8)

polyamide resin;
Based on 100 parts by weight of the polyamide resin, 5 to 20 parts by weight of an EBA-based impact resistant agent, 5 to 10 parts by weight of an EAA-based impact resistant agent; and 0.1 to 1.0 parts by weight of a release agent,
The polyamide resin is mixed with polyamide 6 and polyamide 66 in a weight ratio of 4:6 to 6:4,
The EBA-based impact resistant agent consists of a compound grafted with 0.5 to 5 parts by weight of at least one of α,β-unsaturated carboxylic acid, α,β-unsaturated anhydride, and derivatives thereof to 100 parts by weight of an ethylene butyl acrylate copolymer It is at least one selected from the group,
The EAA-based impact resistant agent is a compound in which 0.5 to 5 parts by weight of at least one of α,β-unsaturated carboxylic acid, α,β-unsaturated anhydride and derivatives thereof is grafted to 100 parts by weight of the ethylene acrylic acid copolymer. A polyamide resin composition, characterized in that at least one selected from 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. delete delete According to claim 1,
The release agent is a polyamide resin composition of 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 3 and 6. The polyamide resin molded article according to claim 7, wherein the insertion force of the molded article is 2 kgf/cm ² or more, the detachment force is 20 kgf/cm ² or more, and the impact resistance is 7 kgf/cm ^{2 or more.}