JP4868396B2 - Nylon-6 / polyvinylidene fluoride blend film and method for producing the same - Google Patents

Description

  The present invention relates to a multiaxial crystal orientation material comprising a nylon-6 / polyvinylidene fluoride blend and a method for producing the same.

Conventionally, a molded body made of polyvinylidene fluoride and nylon 12 and fibrillated with a molded body exhibiting an anisotropic molten form (liquid crystal) and having excellent chemical resistance, wear resistance, and mechanical properties has been disclosed. Yes. (See Patent Document 1)
In addition, it is known that there is a specific interaction between the amide group of nylon and the CF bond of PVdF from the shift of the band of the infrared absorption spectrum and the composition dependence of the glass transition. (See Non-Patent Document 1)
Japanese Patent No. 2614649 Q. Gao, JI Scheibeim, Macromolecules, 33, 7564 (2000) '' Dipolar Intermolecular Interactions, Structural Development, and Electromechanical Properties in Ferroelectric Polymer Blends of Nylon-11 and Poly (vinylidene fluoride)

  The present invention has excellent physical properties such as piezoelectricity, chemical resistance, abrasion resistance, heat resistance, strength and elastic modulus in the nylon-6 / polyvinylidene fluoride blend, but further improved mechanical properties. is necessary. By crystallizing PVdF in an orientation matrix of nylon-6 and controlling the orientation of PVdF, a multiaxial crystal orientation material composed of nylon-6 / polyvinylidene fluoride blend was prepared, and the nylon-6 / polyvinylidene fluoride blend Improve mechanical properties.

A blend film made of nylon-6 and polyvinylidene fluoride (PVdF), in which the crystal axis in the molecular chain direction (c-axis) of nylon-6 and the crystal axis in the direction perpendicular to the molecular chain of polyvinylidene fluoride (b-axis) are both stretch directions A multiaxial crystal orientation material oriented in the direction is prepared.
Specifically, nylon-6 / PVdF is kneaded with a kneading extruder, then formed into a sheet shape with a hot press, and uniaxially stretched. Thereafter, PVdF is melted at a temperature lower than the melting point of nylon-6 and higher than the melting point of PVdF, and the uniaxially stretched sheet-like molded product is gradually cooled at a temperature lowering rate of 20 ° C./min or less to 20 ° C./min or less. A multiaxial crystal alignment material is obtained by slowly cooling at a cooling rate to crystallize PVdF. That is,
The present invention is a blend film made of nylon-6 and polyvinylidene fluoride (PVdF), wherein the crystal axis in the molecular chain direction (c axis) of nylon-6 and the crystal axis in the direction perpendicular to the molecular chain of polyvinylidene fluoride (b) (Axis) is a multiaxial crystal orientation material in which both are oriented in the stretching direction.
Moreover, in this invention, it can be set as nylon-6: polyvinylidene fluoride (PVdF) = 20-70: 80-30 (mass ratio).
In the present invention, nylon-6 / PVdF is kneaded with a kneading extruder, then formed into a sheet by hot press, and uniaxially stretched, and then at a temperature lower than the melting point of nylon-6 and higher than the melting point of PVdF. This is a method for producing a multiaxial crystal alignment material characterized in that PVdF is melted and uniaxially stretched, and a sheet-like molded product is slowly cooled at a temperature lowering rate of 20 ° C./min or less to crystallize PVdF.

  The multiaxial crystal alignment material in which the crystal axis (c-axis) in the molecular chain direction of nylon-6 of the present invention and the crystal chain (b axis) in the direction perpendicular to the molecular chain of polyvinylidene fluoride are aligned in the stretching direction is nylon- By crystallizing PVdF in the orientation matrix of 6 and controlling the orientation of PVdF, the stretching direction is maintained while maintaining the excellent physical properties (chemical resistance, wear resistance, piezoelectricity) of PVdF. The breaking strength and elastic modulus were improved in two directions, and the mechanical properties could be improved.

BEST MODE FOR CARRYING OUT THE INVENTION

The blend of nylon- 6 and polyvinylidene fluoride (PVdF) used in the present invention may have any blending ratio, but nylon- 6: polyvinylidene fluoride = 20-80: 80-20 (mass ratio), More preferably, nylon- 6: polyvinylidene fluoride = 20 to 70:80 to 30 (mass ratio) is preferable.
For example, if a typical example is shown, nylon-6 and PVdF powder are mixed (mixing mass ratio: nylon-6 / PVdF = 20/80 to 70/30), introduced into a kneading extruder, and melted. Knead and extrude. The temperatures of the cylinder and the die are 230-260 ° C. and 230-250 ° C. (preferably 230-250 ° C. and 235-245 ° C., respectively). Thereafter, it is melted at 230-235 ° C. with a hot press and formed into a sheet. Furthermore, it is uniaxially stretched at 2 times or more (preferably 4 times or more) at 20 to 180 ° C., preferably 120 to 150 ° C. Then, after constraining the form, PVdF was melted at a temperature lower than the melting point of nylon-6 and higher than the melting point of PVdF (preferably 180 to 190 ° C.), and then the rate of temperature decrease of 20 ° C./min or less (preferably Slow cooling at 5 ° C./min or less) to crystallize PVdF.

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Nylon-6 and PVdF powder are mixed (mixing ratio: nylon-6 / PVdF = 5/5), introduced into a kneading extruder, kneaded in a molten state and extruded. The cylinder and die temperatures are 245 ° C and 240 ° C, respectively. Thereafter, it is melted at 233 ° C. with a hot press and formed into a sheet. Furthermore, it is uniaxially stretched 4.5 times at 145 ° C. Thereafter, the morphology was constrained, and PVdF was melted at 180 ° C. for 2 minutes, and then slowly cooled at a temperature decrease rate of 0.5 ° C./min to crystallize PVdF.
When observed with an electron microscope, it is observed that PVdF domains having a diameter of 0.1 to 0.5 μm and a length of 5 to 10 μm are arranged in a nylon alignment matrix (FIG. 6). According to wide-angle X-ray diffraction, for nylon, the crystal axis in the molecular chain direction (crystal c axis) is oriented in the stretching direction, whereas for PVdF, the crystal b axis, which is the crystal axis perpendicular to the molecular chain. It can be confirmed that is oriented in the stretching direction and a multiaxial crystal orientation structure is formed (FIG. 1).
According to the tensile test, the breaking strength was 151 MPa, the breaking elongation was 25.1%, and the tensile modulus was 2.46 GPa in the drawing direction. In the direction perpendicular to the stretching, the breaking strength was 57 MPa, the breaking elongation was 5.8%, and the tensile modulus was 1.4 GPa, indicating excellent mechanical properties in two directions (FIG. 4).

Similarly to Example 1, with respect to a blend sample having a composition of nylon-6 / PVdF = 2/8, the shape of the stretched membrane was constrained, and PVdF was melted at 180 ° C. for 2 minutes, and then the temperature was lowered by 0.5 ° C./minute. The PVdF was crystallized by slow cooling at a rate. Wide-angle X-ray diffraction confirmed that a multiaxial crystal orientation structure was formed (FIG. 3).
According to the tensile test, the breaking strength was 117 MPa, the breaking elongation was 16.9%, and the tensile modulus was 2.0 GPa in the drawing direction. Further, in the direction perpendicular to the stretching, the breaking strength was 55 MPa, the breaking elongation was 6.6%, and the tensile modulus was 1.3 GPa, and excellent mechanical properties were exhibited in two directions (FIG. 5).

(Comparative Example 1)
The mechanical properties of the unstretched film (non-oriented film) of the blend sheet (nylon-6 / PVdF = 5/5) were evaluated. The yield strength was 42 MPa, the yield elongation was 14.8%, the breaking strength was 53 MPa, the breaking elongation was 418%, and the tensile modulus was 0.70 GPa (FIG. 4).
(Comparative Example 2)
The mechanical properties of the unstretched film (non-oriented film) of the blend sheet (nylon-6 / PVdF = 2/8) were evaluated. The yield strength was 50 MPa, the yield elongation was 14.7%, the breaking strength was 42 MPa, the breaking elongation was 204%, and the tensile modulus was 0.86 GPa (FIG. 5).

  The multiaxial crystal orientation material of the present invention can be applied to a wide range of uses as various structural materials such as a high-strength plastic film and has high industrial applicability.

After stretching, PVdF was melted at 180 ° C for 2 minutes and then slowly cooled at a rate of temperature decrease of 0.5 ° C / min to crystallize PVdF. Wide-angle X-ray diffraction image (left) and wide-angle X-ray diffraction profile (right) After stretching, PVdF was melted at 180 ° C for 2 minutes and then slowly cooled at a temperature drop rate of 0.5 ° C / min to crystallize PVdF (mixing ratio: nylon-6 / PVdF = 35/65) Wide-angle X-ray diffraction image (left) and wide-angle X-ray diffraction profile (right) After stretching, PVdF was melted at 180 ° C for 2 minutes and then slowly cooled at a temperature drop rate of 0.5 ° C / min to crystallize PVdF (mixing ratio: nylon-6 / PVdF = 20/80) Wide-angle X-ray diffraction image (left) and wide-angle X-ray diffraction profile (right) After stretching, PVdF was melted at 180 ° C for 2 minutes and then slowly cooled at a rate of temperature decrease of 0.5 ° C / min to crystallize PVdF. Stress-strain curve (solid line and alternate long and short dash line) and unstretched film (non-oriented film) of blend sheet (nylon-6 / PVdF = 50/50) After stretching, PVdF was melted at 180 ° C for 2 minutes and then slowly cooled at a temperature drop rate of 0.5 ° C / min to crystallize PVdF (mixing ratio: nylon-6 / PVdF = 20/80) Stress-strain curve (solid line and alternate long and short dash line) and unstretched film (non-oriented film) of blend sheet (nylon-6 / PVdF = 20/80) After stretching, PVdF was melted at 180 ° C for 2 minutes and then slowly cooled at a rate of temperature decrease of 0.5 ° C / min to crystallize PVdF. Scanning electron micrograph After stretching, PVdF was melted at 180 ° C for 2 minutes and then slowly cooled at a temperature drop rate of 0.5 ° C / min to crystallize PVdF (mixing ratio: nylon-6 / PVdF = 20/80) Scanning electron micrograph

Claims (2)

A blend film made of nylon-6 and polyvinylidene fluoride (PVdF). Both the crystal axis in the molecular chain direction (c-axis) of nylon-6 and the crystal axis in the direction perpendicular to the molecular chain of polyvinylidene fluoride (b-axis) are both Oriented in the stretching direction and made of nylon-6: polyvinylidene fluoride (PVdF) = 20 to 70:80 to 30 (mass ratio), the PVdF domain diameter is 0.1 to 0.5 μm, and the PVdF domain The multiaxial crystal alignment material is characterized by having a length of 5 to 10 μm . Nylon-6 / PVdF is kneaded with a kneading extruder, then formed into a sheet shape by hot pressing, uniaxially stretched , then PVdF is melted at 180-190 ° C., and the uniaxially stretched sheet-like molded product is 5 ° C./min. A method for producing a multiaxial crystal alignment material, wherein PVdF is crystallized by slow cooling at the following temperature drop rate.

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