KR20190036246A - Polyamide Resin Compositions For Improving and Molding Produced from the same - Google Patents

Abstract

The present invention relates to a polyamide resin composition. The polyamide resin composition comprises, with respect to the total weight of the polyamide resin composition: 45-70 wt% of a polyamide resin; 0.1-1 wt% of a heat-resistant agent; 0.1-1 wt% of a releasing agent; 0.8-1.5 wt% of a viscosity controlling agent; and 30-50 wt% of a filler. In particular, the polyamide is one selected from polyamide 6 and polyamide 66, a flowability improving agent is bis(hydroxymethyl) propandiol-based, and the filler is a flat fibrous glass fiber filler. The polyamide resin composition of the present invention has desirable tensile strength, flexural rigidity, flexural modulus, and impact strength; can improve surface properties and dimensional stability; and can reduce warpage. Also, the polyamide resin composition of the present invention may provide a molded article with reinforced surface properties, improved dimensional stability, and reduced warpage.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyamide resin composition and a molded article produced therefrom,

The present invention relates to a polyamide resin composition and a molded article produced therefrom.

Automobile materials have been replaced by engineering plastics from metals such as aluminum and steel due to various environmental regulations and high oil prices. Engineering plastic materials are widely used in automobile interior and exterior materials, and various parts are being used from thin and wide parts to very thick, small and large parts. In addition, demand for engineering plastic materials is increasing not only in automobiles but also in various home appliances. Therefore, researches are being carried out to satisfy the properties required for application fields of engineering plastics which are lightweight compared to existing materials. In order to satisfy the physical properties of existing materials, engineering plastics have been added with a variety of fibrous and particulate fillers to enhance the physical properties of engineering plastics. However, as the content of the filler increases, the flowability decreases and the surface properties as well as the warpage and dimensional stability deteriorate .

Korean Patent Laid-Open No. 10-2013-0061388 discloses a polyamide (PA) in which polyethylene terephthalate (PET), a compatibilizer, a glass fiber coated with a silane coupling agent, a phenol-based and phosphite-based antioxidant, There is a problem that warpage occurs in the flow direction due to the addition of PET and the surface protrusion of the glass fiber becomes prominent.

Korean Patent No. 10-1740664 discloses a polyamide-based composite material comprising a polyamide-based resin, glass fiber, and a flow control agent, which reduces the friction between the molten resin and the processing machine and effectively prevents the polyamide- There is a disadvantage in that it can not simultaneously satisfy surface characteristics, dimensional stability, warpage, and flow characteristics.

Accordingly, development of a polyamide resin composition which is not warped in the flow direction when applied to a large-sized component, has excellent dimensional stability, can prevent the surface protrusion of the glass fiber and can improve the surface characteristics is desired.

Accordingly, it is an object of the present invention to provide a polyamide-reinforced resin composition excellent in physical properties of mechanical strength and bending elastic modulus, warped and dimensional stability are secured, flow characteristics are improved, and surface characteristics are excellent.

Accordingly, in one preferred embodiment of the present invention, 0.4 to 1.0 parts by weight of an antioxidant, 0.3 to 0.9 parts by weight of a release agent, 0.2 to 3.0 parts by weight of a flowability improver, and 44 to 105 parts by weight of a filler are added to 100 parts by weight of a polyamide resin Wherein the polyamide resin is at least one selected from the group consisting of polyamide 6 and polyamide 66, the flow improver is bishydroxymethyl propane diol type, and the filler is a flat fibrous glass fiber filler A polyamide resin composition is provided.

The polyamide resin has a relative viscosity of 2.4 to 3.2.

The antioxidant is at least one selected from the group consisting of a phenol-based antioxidant, a phosphite-based antioxidant, and a mixture thereof.

The release agent is characterized by being at least one selected from the group consisting of an ethylenebisstearamide-based resin, a polyethylene-based resin, an ester-based release agent, and mixtures thereof.

The flat fibrous glass fiber filler is characterized by being a flat planar fibrous phase having a cross-sectional aspect ratio of 4 or more.

The present invention provides, as another preferred embodiment, a molded article produced from a polyamide resin composition.

INDUSTRIAL APPLICABILITY The present invention can provide a polyamide resin composition having excellent tensile strength, flexural strength, flexural modulus and impact strength, and improved surface characteristics, dimensional stability and warpage.

Further, the polyamide resin composition according to the present invention can provide a molded article enhanced in surface characteristics, improved in dimensional stability and warping.

According to one aspect of the present invention, there is provided a polyamide resin composition comprising 0.4 to 1.0 parts by weight of an antioxidant, 0.3 to 0.9 parts by weight of a release agent, 0.2 to 3.0 parts by weight of a flowability improver, and 44 to 105 parts by weight of a filler, Wherein the polyamide resin is at least one selected from the group consisting of polyamide 6 and polyamide 66, the flow improver is bishydroxymethylpropane diol type, and the filler is a flat fibrous filler. to provide.

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

[Polyamide resin]

The polyamide resin according to the present invention may be at least one selected from polyamide 6 (PA6) and polyamide 66 (PA66).

The polyamide resin preferably has a relative viscosity of 2.4 to 3.2 as measured when 20 g of polyamide 6 resin is added to 100 ml of 96% sulfuric acid. If the relative viscosity of the polyamide resin is less than 2.4, mechanical strength and the like may be lowered and a problem of warping may occur. When the relative viscosity of the polyamide resin is more than 3.2, the viscosity of the polyamide resin is high and the fluidity of the polyamide resin is lowered.

[Antioxidant]

The antioxidant according to the present invention can prevent the resin from aging due to heat during processing and injection. The antioxidant is preferably at least one of a phenol antioxidant, a phosphite antioxidant, and a mixture thereof.

The antioxidant may be 0.4 to 1.0 part by weight based on 100 parts by weight of the polyamide resin. When the heat resistant agent is less than 0.4 part by weight, there is a problem that the heat resistance characteristic is insufficient. On the other hand, when the heat resistant agent exceeds 1.0 part by weight, the production cost increases.

[ Release agent ]

The release agent according to the present invention can improve releasability upon injection. The releasing agent may be one or more of an ethylenebisstearamide-based, a polyethylene-based, an ester-based releasing agent and a mixture thereof, preferably an ethylenebisstearamide-based releasing agent.

The release agent may be 0.3 to 0.9 parts by weight based on 100 parts by weight of the polyamide resin. If the release agent is less than 0.3 part by weight, there is a problem that mold releasing property is poor. On the other hand, if the release agent exceeds 0.9 parts by weight, the production cost increases.

[Flowability improver]

The flowability improver according to the present invention can improve the flowability of the polymer material during extrusion and extrusion. The flow improver may be at least one member selected from the group consisting of benzene dicarboxylic acid, bis hydroxymethyl propane diol, and mixtures thereof, and is preferably a bishydroxymethyl propane diol flow improver.

The flowability improver may be 0.2 to 3.0 parts by weight based on 100 parts by weight of the polyamide resin. When the flowability improver is less than 0.2 part by weight, there is a problem that the effect on the improvement of flowability may not be obtained. On the other hand, when the flowability improver is used in an amount exceeding 3.0 parts by weight, there is a problem that it interferes with the kneading of the polymer composite or mechanical strength because it acts as an unintended lubricant.

[Filler]

The filler according to the present invention can improve the mechanical properties, dimensional stability and warping of the resin. The filler may be a flat fibrous glass fiber filler.

The filler may be 44 to 105 parts by weight based on 100 parts by weight of the polyamide resin. When the amount of the filler added is less than 44 parts by weight, the desired mechanical strength can not be obtained. When the amount of the filler is more than 105 parts by weight, surface and formability are poor.

The flat fibrous glass fiber filler may be a flat planar fibrous shape having a cross-sectional aspect ratio of not less than 4 but not a cylindrical fibrous shape. When the above-mentioned range is satisfied, there is an advantage that the portion protruding to the injection surface is fewer and the surface characteristics are smoother than the case of using the cylindrical filament type.

According to one aspect of the present invention, the polyamide resin composition can provide a molded article enhanced in surface characteristics, improved in dimensional stability and warping.

[ 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 merely illustrative of the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

Example  One

100 parts by weight of polyamide 6 (DOMO Chemical, Domamid 27), 0.5 part by weight of an antioxidant (ASC, BB98240, a mixture of a phenolic antioxidant and a phosphite antioxidant), a mold release agent (Shin- 0.25 parts by weight of a flowability improver (Samyang Chemical, pentaerythritol; bishydroxymethylpropane diol type) and 103.9 parts by weight of a filler (Nittobo, CSG-3PA-820; flat fiber glass fiber) Kneaded in a twin-screw extruder, and cooled to prepare a polyamide resin composition.

Example  2 and 3

Except that the content of the flowability improver (Samyang Chemical, pentaerythritol; bishydroxymethylpropanediol-based) was changed as shown in the following Table 1, Amide resin compositions were prepared.

Example  4

As shown in the following Table 1, except that the polyamide resin 66 (ASCEND, 50BWFS) was used in place of the polyamide 6 resin, and the weight of the flowability improver was changed, the procedure of Example 4 was repeated, Thereby preparing a polyamide resin composition.

Comparative Example  One

As shown in the following Table 1, the polyamide resin composition of Comparative Example 1 was prepared in the same manner as in Example 1, except for the flow improver.

Comparative Example  2 and 3

The polyamide resin compositions of Comparative Examples 2 and 3 were prepared in the same manner as in Example 1, except that the content of the flow improver was changed to fall outside the preferred range as shown in Table 1 below.

Comparative Example  4 to 6

Except that the flowability improver (Samyang Chemical, pentaerythritol; bishydroxymethylpropane diol type) was changed to a flow improver (Tae Kwang Industry, terephthalic acid, benzene dicarboxylic acid) as shown in the following Table 1 The polyamide resin compositions of Comparative Examples 4 to 6 were prepared in the same manner as in Example 1,

Comparative Example  7

(KCC, CS-311; cylindrical glass fiber) instead of the filler (Nittobo, flat fibrous glass fiber CSG-3PA-820) as shown in the following Table 1, The polyamide resin composition of Comparative Example 7 was prepared.

Comparative Example  8

(KCC, CS-311; cylindrical glass fiber) in place of the filler (Nittobo, flat fibrous glass fiber CSG-3PA-820) as shown in the following Table 1 and the content of the flow improver , A polyamide resin composition of Comparative Example 8 was prepared in the same manner as in Example 1.

Comparative Example  9

Except that the polyamide resin 66 (ASCEND, 50BWFS) was used in place of the polyamide 6 resin and the flowability improver was replaced with the polyamide resin composition of Comparative Example 9 in the same manner as in Example 1, .

division PA6 PA66 Antioxidant Release agent Flowability improving agent ¹⁾ Flowability improving agent ²⁾ Flat fiberglass fiberglass Cylindrical glass fiber Example 1 100 - 0.5 0.4 0.25 - 103.9 - Example 2 100 - 0.5 0.4 1.5 103.9 - Example 3 100 - 0.5 0.4 3.0 103.9 - Example 4 - 100 0.5 0.4 1.5 - 103.9 - Comparative Example 1 100 - 0.5 0.4 - - 103.9 - Comparative Example 2 100 - 0.5 0.4 0.1 - 103.9 - Comparative Example 3 100 - 0.5 0.4 4.0 103.9 - Comparative Example 4 100 - 0.5 0.4 - 0.25 103.9 - Comparative Example 5 100 - 0.5 0.4 - 1.5 103.9 - Comparative Example 6 100 - 0.5 0.4 - 3.0 103.9 - Comparative Example 7 100 0.5 0.4 - - - 103.9 Comparative Example 8 100 - 0.5 0.4 1.5 - - 103.9 Comparative Example 9 - 100 0.5 0.4 - - 103.9 - Flow improvers ^{1 )} : Samyang Chemical, pentaerythritol; Bis hydroxymethyl propanediol system
Flow improver ^{2 )} : Taekwang Industry, terephthalic acid; Benzene dicarboxylic acid

Specimens were prepared by injection molding the polyamide resin compositions prepared in Examples and Comparative Examples using ASTM molds.

Tensile strength, flexural strength, flexural modulus, impact strength, shrinkage percentage, flexural strength, and surface condition were measured in the following manner, and the results are shown in Table 2.

(1) Tensile strength

According to ASTM D638, the tensile strength was measured with UTM (INSTRON 3367) under the condition of 5 mm / min.

(2) Flexural strength

According to ASTM D790, flexural strength was measured with UTM (INSTRON 3367) under the condition of 3 mm / min.

(3) Flexural modulus

The flexural modulus was measured with UTM (INSTRON 3367) under the condition of 3 mm / min according to ASTM D790.

(4) Impact strength

Based on ASTM D256, the Izod notched impact strength was measured at room temperature (23 DEG C) and under a condition of 2.75J.

(5) Shrinkage

In accordance with ISO 294, shrinkage in the direction of flow (MD) and in the perpendicular direction (TD) was measured around the gate after leaving the specimen at room temperature and 50% absolute humidity for 48 hours.

(6) Whether to warp

It was visually confirmed.

(O: none, B: fine crack, X: visible deflection)

(7) Surface state

Relative comparison and visual confirmation.

(?: Very good,?: Good,?: Fair, X: poor)

division The tensile strength
(MPa) Flexural strength
(MPa) Flexural modulus
(MPa) Impact strength
(kgfcm / cm) Shrinkage rate
(%) MD Shrinkage rate
(%) TD Bending state Surface condition Example 1 207 301 13725 118.1 0.181 0.242 ○ ◎ Example 2 210 310 14163 119.4 0.173 0.231 ○ ◎ Example 3 212 312 14574 120.3 0.170 0.230 ○ ◎ Example 4 209 297 13734 116.3 0.175 0.234 ○ ◎ Comparative Example 1 204 294 13101 115.6 0.195 0.255 △ △ Comparative Example 2 205 298 13187 116.7 0.186 0.246 ○ ○ Comparative Example 3 189 278 12465 102.4 0.170 0.229 ○ ○ Comparative Example 4 198 282 13071 101.2 0.180 0.239 ○ ◎ Comparative Example 5 185 273 12883 87.4 0.172 0.230 ○ ◎ Comparative Example 6 179 268 12781 73.9 0.171 0.228 ○ ◎ Comparative Example 7 202 292 13002 113.7 0.203 0.455 X X Comparative Example 8 208 307 14078 114.2 0.194 0.421 X X Comparative Example 9 206 295 13403 115.1 0.194 0.251 △ △

As a result of measurement of the physical properties, as shown in Table 2, the antioxidant, the release agent, the flow improver and the filler were optimally contained in the polyamide resin based on Examples 1 to 4 according to the present invention, The shrinkage ratio is lower than that in the case of using a cylindrical fibrous phase, the difference in the shrinkage ratio in the flow direction and the shrinkage ratio in the perpendicular direction is minimized, and the excellent surface state .

On the other hand, in Comparative Examples 1 to 3, the flowability improver was set to deviate from the optimum range, and the mechanical strength and the shrinkage ratio were similar to each other below the optimal range, but the flexural state and the surface state were good, , It was confirmed that the mechanical strength was lowered.

Comparative Examples 4 to 6 were obtained by using flow improvers different from those of the Examples. When the same flow improvers were used, the warpage and the surface state were excellent, but the mechanical strength was lower than that of the Examples .

Comparative Examples 7 and 8 are examples which are compared with Comparative Example 1 and Example 2, respectively, and a cylindrical fibrous shape which is not a flat fibrous shape was used. The mechanical properties were similar to those of Example, but the warping phenomenon and the surface condition were poor have.

Comparative Example 9 is an example to be compared with Example 4, and PA66, which is not PA6, is used, and a flow property improver is not used, and it can be confirmed that the mechanical properties, the shrinkage rate and the bending phenomenon surface state are poor.

Claims (6)

0.4 to 1.0 parts by weight of an antioxidant, 0.3 to 0.9 parts by weight of a release agent, 0.2 to 3.0 parts by weight of a flow improver, and 44 to 105 parts by weight of a filler, based on 100 parts by weight of the polyamide resin,
The polyamide resin is at least one selected from polyamide 6 and polyamide 66,
Wherein the flow improver is bishydroxymethyl propane diol type,
Wherein the filler is a flat fibrous glass fiber filler. The polyamide resin composition according to claim 1, wherein the polyamide resin has a relative viscosity of 2.4 to 3.2. The polyamide resin composition according to claim 1, wherein the antioxidant is at least one selected from the group consisting of a phenol antioxidant, a phosphite antioxidant, and a mixture thereof. The polyamide resin composition according to claim 1, wherein the releasing agent is at least one selected from the group consisting of an ethylenebisstearamide-based, a polyethylene-based, an ester-based releasing agent and a mixture thereof. The polyamide resin composition according to claim 1, wherein the flat fibrous glass fiber filler is a flat planar fibrous phase having a cross-sectional aspect ratio of 4 or more. A molded article produced from the polyamide resin composition according to any one of claims 1 to 5.