Polymer resin composition and vinylidene fluoride-based polymer molded product

Abstract

The present invention relates to a polymer resin composition including: a vinylidene fluoride-based polymer resin; and one or more types of nucleating agents selected from the group consisting of an organic phosphate and a C.sub.5-C.sub.15 bicycloalkane substituted with one or more carboxylic acid metal salt functional groups, and a polymer resin molded product prepared using the polymer resin composition.

Claims

1. A polymer resin composition comprising: a vinylidene fluoride-based polymer resin; and one or more types of nucleating agents selected from the group consisting of an organic phosphate and a C.sub.5-C.sub.15 bicycloalkane substituted with one or more carboxylic acid metal salt functional groups, wherein the C.sub.5-C.sub.15 bicycloalkane substituted with one or more carboxylic acid metal salt functional groups includes bicyclo[2.2.1]heptane or bicyclo[2.2.2]octane substituted with one to four functional groups selected from the group consisting of a lithium carboxylate group, a sodium carboxylate group, and a potassium carboxylate group, wherein the organic phosphate includes an aromatic phosphate ester metal salt, wherein the aromatic phosphate ester metal salt includes a compound represented by the following Chemical Formula 1: ##STR00004## wherein, in Chemical Formula 1, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, and R.sub.8 are the same as or different from each, and are each independently hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms, X is a linear or branched alkylene group having 1 to 5 carbon atoms, n is 1 or 2, when n is 1, M is an alkali metal, and when n is 2, M is an alkaline earth metal or hydroxy-aluminum, wherein the polymer resin composition includes 0.01 to 5 parts by weight of the nucleating agent relative to 100 parts by weight of the vinylidene fluoride-based polymer resin.

2. The polymer resin composition according to claim 1, wherein the vinylidene fluoride-based polymer resin has a melt index (230? C., load of 5 kg) of 0.1 to 30 g/10 min.

3. The polymer resin composition according to claim 1, wherein the vinylidene fluoride-based polymer resin has a weight average molecular weight of 100,000 to 1,000,000.

4. The polymer resin composition for the preparation of a hollow fiber membrane according to claim 1, comprising one or more selected from the group consisting of a vinylidene fluoride homopolymer and a vinylidene fluoride copolymer.

5. The polymer resin composition according to claim 1, further comprising at least one additive selected from the group consisting of an antioxidant, a lubricant, a heat resistant agent, a UV stabilizer, a neutralizing agent, a pigment, a scratch resistance improving agent, and a deodorant.

6. A vinylidene fluoride-based polymer resin molded product comprising a melt extrudate of the polymer resin composition of claim 1.

7. The vinylidene fluoride-based polymer resin molded product according to claim 6, wherein a flexural modulus of the molded product measured according to ASTM D790 is 20,000 kgf/cm.sup.2 or more.

8. The vinylidene fluoride-based polymer resin molded product according to claim 6, wherein tensile strength of the molded product measured according to ADTM D638 is 530 kgf/cm.sup.2 or more.

9. The vinylidene fluoride-based polymer resin molded product according to claim 6, wherein relative crystallinity of the molded product is 60% to 75%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an XRD graph obtained in Experimental Example 3.

(2) FIG. 2 shows a SEM enlarged image (?100 times) obtained in Experimental Example 4.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(3) Hereinafter, the present invention will be described in more detail in the following examples. However, these examples are for illustrative purposes only, and the contents of the invention are not intended to be limited by these examples.

EXAMPLES AND COMPARATIVE EXAMPLES: PREPARATION OF VINYLIDENE FLUORIDE-BASED POLYMER RESIN MOLDED PRODUCT

Example 1

(4) 0.3 parts by weight of a vinylidene fluoride-based polymer resin [melt index (230? C., load of 5 kg): about 10 g/10 min] and an aromatic phosphoric acid ester metal salt represented by the following Chemical Formula 1 were mixed in a Henschel mixer for 3 min, and then extruded with a twin-screw extruder at about 220? C. to obtain a pellet-shaped resin composition having a diameter of about 1 to 2 mm.

(5) A tensile strength test piece (ASTM D 638), a flexural modulus test piece (ASTM D790), and an Izod impact strength test piece (D258) were prepared from the pellet-shaped resin composition prepared above using a 150 ton molding extrusion machine (DONGSHIN Hydraulics, PRO-150WD).

(6) ##STR00003##

Example 2

(7) The resin molded product and the test piece were prepared in the same manner as in Example 1, except that disodium cis-endo-bicyclo(2.2.1) heptane-2-3-dicarboxylate was used instead of the aromatic phosphoric acid ester metal salt of Chemical Formula 1.

Comparative Example

(8) The resin molded product and the test piece were prepared in the same manner as in Example 1, except that the aromatic phosphoric acid ester metal salt of Chemical Formula 1 was not used.

EXPERIMENTAL EXAMPLES: MEASUREMENT AND OBSERVATION OF PHYSICAL PROPERTIES OF VINYLIDENE FLUORIDE-BASED POLYMER RESIN MOLDED PRODUCT

Experimental Example 1: Measurement of Melting Point (Tm) and Crystallization Temperature (Tc)

(9) The melting point (Tm) and the crystallization temperature (Tc) of the vinylidene fluoride-based polymer resin molded product obtained in the examples and comparative example were measured by using differential scanning calorimetry (DSC).

(10) 5 mg of the test pieces obtained in the examples and comparative example were melted at 220? C. for 5 min and then cooled at a cooling rate of 10? C./min in order to completely remove the thermal history, and thereby the crystallization temperature and the generated heat amount were measured. The molded product crystallized at room temperature was again heated to 220? C. at a rate of 10? C./min to measure the melting point and the amount of heat absorbed.

(11) Under these conditions, the crystallization temperature (Tc), the crystallization time (s), and the melting point were measured.

(12) TABLE-US-00001 TABLE 1 DSC measurement results Crystallization temperature (Tc) Crystallization time Melting point Comparative 134? C. 76 s 170? C. Example 1 Example 1 145? C. 68 s 172? C. Example 2 138? C. 73 s 170? C.

(13) As shown in Table 1 above, it was confirmed that the vinylidene fluoride-based polymer resin molded products obtained in Examples 1 and 2 had not only a higher crystallization temperature and melting point but also a relatively short crystallization time, as compared with Comparative Example 1.

(14) Specifically, the vinylidene fluoride-based polymer resin molded products obtained in Examples 1 and 2 exhibited a crystallization temperature of 135? C. or more and a melting point of 170? C. or more.

Experimental Example 2: Measurement of Melt Index, Tensile Strength, and Flexural Modulus

(15) The melt index, tensile strength, flexural modulus, and Izod impact strength of the vinylidene fluoride-based polymer resin molded products obtained in the examples and comparative example were measured by the methods shown in Table 2 below.

(16) TABLE-US-00002 TABLE 2 Measurement results of the melt index, tensile strength and flexural modulus Measurement Comparative method Example Example 1 Example 2 Melt index ASTM D1238 6.6 6.0 6.2 (g/min) 230? C., 5 kg Tensile strength ADTM D638 520 540 535 (kgf/cm.sup.2) Temperature 23? C./ relative humidity 50% Flexural modulus ASTM D790 19,000 21,000 20,600 (kgf/cm.sup.2) Temperature 23? C./ relative humidity 50% IZOD impact ASTM D256 28.3 28.1 28.0 strength (23? C., 3T) (kgf .Math. cm/cm)

(17) As shown in Table 2 above, it was confirmed that the vinylidene fluoride-based polymer resin molded products obtained in Examples 1 and 2 had higher tensile strength and flexural modulus than the resin molded products of the comparative example, and also had equivalent impact strength to that of the comparative example.

(18) Specifically, the vinylidene fluoride-based polymer resin molded products obtained in Examples 1 and 2 had a flexural modulus of 20,000 kgf/cm.sup.2 and tensile strength of 530 kgf/cm.sup.2 or more.

Experimental Example 3: Measurement of Relative Crystallinity of the Vinylidene Fluoride-Based Polymer Resin Molded Products

(19) X-ray diffraction analysis (XRD) was performed for the vinylidene fluoride-based polymer resin molded products obtained in Examples 1 and 2 by reflection in the temperature range of 0? C. to 70? C., and the relative crystallinity of the vinylidene fluoride-based polymer resin molded products was determined by using the area ratio of the peaks with a generated FWHM of 2.5 or less.

(20) The obtained X-ray diffraction analysis graph is shown in FIG. 1.

(21) TABLE-US-00003 TABLE 3 Relative crystallinity measured by XRD X-ray diffraction (XRD) Relative crystallinity (FWHM <2.5) Comparative Example 52.6% Example 1 63.6% Example 2 62.2% FWHM = Full width at half maximum Crystallinity = (Area of crystalline peak/(area of crystalline peak + area of amorphous peak) ? 100

(22) As shown in Table 3 above, it was confirmed that the vinylidene fluoride-based polymer resin molded products of Examples 1 and 2 had higher relative crystallinity than that of the comparative example, and specifically had relative crystallinity of 60% to 70%.

(23) It was also confirmed that the scattering peaks of the vinylidene fluoride-based polymer resin molded products of Example 1 and Example 2 were stabilized as compared with the ?-type X-ray scattering peak of the vinylidene fluoride-based polymer resin molded product of the comparative example.

Experimental Example 4: Observation of Crystal Growth Size Using SEM

(24) The vinylidene fluoride-based polymer resin molded products obtained in the examples and comparative example were observed using a heating stage and SEM.

(25) Specifically, the test pieces of the vinylidene fluoride-based polymer resin molded products obtained in the examples and comparative example were heated up to 220? C. using a heating stage and completely melted for 5 min, followed by isothermal crystallization at 162? C., and the crystallization behavior of the test pieces was measured through SEM.

(26) As shown in FIG. 2, it was confirmed that the polymer crystals contained in the vinylidene fluoride-based polymer resin molded products obtained in Example 1 and the comparative example were smaller, whereby in the case of the vinylidene fluoride-based polymer resin molded products of the example, a large number of small crystals were grown to improve the crystallinity and the crystallization temperature as a whole.