JPS5941310A - Molded article of vinylidene fluoride resin - Google Patents

Abstract

PURPOSE:The titled molded article having >=specific values of crystal length in the molecular chain direction and double refraction, high Young's modulus, improved surface properties and transparency. CONSTITUTION:A vinylidene fluoride resin is melted, drawn non-isothermally (a ratio of winding rate to melt extrusion rate in drawing, namely, preferably a draft ratio, is 300-50,000 in the case of molding to filament shape, and >=50 in the case of film), while being cooled (preferably by >=50 deg.C below a temp. for giving the maximum crystallization rate of the resin), to give the desired molded article having >=200Angstrom crystal length in the molecular chain direction, and >=25X10<-3> double refraction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vinylidene fluoride resin molded product having a large Young's modulus and excellent surface properties and transparency.

The conventional vinylidene fluoride resin system with a large Young's modulus is 250 to 300 k17/mm2.
Met. Such a Young's modulus is insufficient for many applications. For example, when it comes to fishing line, the fish confidence is poor, resulting in a low catch rate, and there is no hope for regular thread fishing. Furthermore, the repulsion coefficient of the strings of electronic musical instruments and the strings of tennis rackets is small, and their performance cannot be fully activated. Furthermore, vinylidene fluoride resin has excellent weatherability, so if the Young's modulus is increased, it is expected to be in wide demand for various outdoor applications such as construction materials, industrial GH materials, transportation materials, etc. If Young's modulus is increased with almost no decrease in strength underwater, there are great expectations for marine development.

In addition, vinylidene fluoride resin has the property of transmitting so-called Dorno rays in the wavelength range of 2800 to 3300A, so if it is used as window glass for a solar bathroom, it will be able to obtain ultraviolet rays that are blocked and not transmitted by ordinary glass, which is good for health. Since conventional vinylidene fluoride resin films have a low Young's modulus, they deform and sag even when a slight force is applied, so they must be handled carefully.

In response to such demands, various attempts have been made to increase the Young's modulus of vinylidene fluoride resin molded products. For example, an attempt has been made to apply the ultra-stretching method, which has been successful in achieving a high Young's modulus in polymers with small intermolecular cohesive forces such as polyethylene and polypropylene, to vinylidene fluoride resins with large intermolecular cohesive forces. It is one. As is well known, the super-stretching method involves cold-stretching at a very slow speed with a stretching ratio of 30 to
However, vinylidene fluoride resin, as well as resins with large intermolecular cohesive forces, have not yet been molded by this method.

Furthermore, molded products with a high Young's modulus obtained from resins with low intermolecular cohesive force tend to fibrillate, resulting in poor surface properties (and poor transparency as well as tensile strength that decreases with use). Fiber Science Society Proceedings; 5. Vol 3
8. Seat 6.1982. (See page 279) In view of the current situation, the present invention provides a vinylidene fluoride resin molded product that increases Young's modulus and has excellent surface properties and transparency. The crystal length in the chain direction is 200^ or more, and the Jilli ratio is 2
It is a vinylidene fluoride resin molded product having a value of 5XIQ or higher.

In order to achieve the object of the present invention more completely, the crystalline torque in the molecular chain direction should be 250^ or more, and the birefringence should be 30X10.
As mentioned above, it is preferable that t+4f be 33X10-'' or more.

Here, the crystal length in the molecular chain direction was determined by the following method. That is, in XM diffraction, the diffraction plane 1 perpendicular to the molecular chain direction
Normally, the diffraction plane 1 has the highest diffraction intensity among them. For example, in polyvinylidene fluoride homophomer IJ polymer, the The diffraction intensity at the time of incidence is read on the chart, and the half width of the peak is determined. On the other hand, the mechanical spread under measurement conditions is determined using silicone single crystal powder. The value obtained by subtracting the half-width value of mechanical expansion from the half-width value of the measurement sample is the true half-width value (βW) of the sample.
shall be. Using this true half-width value, calculate the crystal length (Ll) using Scherrer's formula. Here, θ is the Zorag reflection angle of the measured diffraction surface, a constant equal to 1.0, and λ is X#J! This is the wavelength (1,542^) of GuKα.

In addition, the measurement of birefringence (Δn) is obtained by the following formula. Here, the number n of interference fringes is D bond (2
= 589 mt as a light source, and is determined from the cut end of the thread under a polarizing microscope with a polarizer and an analyzer orthogonal to each other. Further, ε is obtained from the portion corresponding to the diameter d of the thread using Berek's condenser. (For example, see "Reiwei Handbook, Raw Materials Edition," p. 969, round neck, November 1968 issue 11.) Such molded products can be produced, for example, by stretching vinylidene fluoride resin from its molten state under non-isothermal conditions while cooling it. can get. At this time, the stretching is performed by controlling the winding speed ratio to the melt extrusion speed, that is, the draft rate, within the following range. In other words, the shape to be formed is a thread)
300 to 50,000°, preferably 500 to 2
0000, even more preferably 1000-15000
When the shape to be molded is a film, the number is 50 or more, preferably 100 or more.

Further, the cooling temperature I2 is lower than the temperature that gives the maximum crystallization rate of the resin, and more preferably, it is performed at a temperature that is 50C or more lower than the temperature that gives the maximum crystallization rate of the resin.

The molded product of the present invention has a large Young's modulus.1For example, when the molded product is a thread, its Young's modulus is 450 ¥-,'? /mm
Get what you want. 11) Leakage 1 For example, in the case of the above method, if the draft rate is increased, a thickness of 600 k'j/mm or more can be obtained depending on the molding conditions. The molded product obtained by this method exhibits an α-type crystal structure.The molded product obtained with such a high draft rate is 11 ceripropylene or polyethylene terephthalate.

Unlike other polymers such as nylon-6, in the case of vinylidene fluoride resin, when the upper F molded product is further cold-stretched by about 10 to 50%, it usually transforms into a β-type crystal structure and surprisingly increases the Young's modulus. Even better, 800k? /m
m or more can be obtained easily. Increase the raft rate (1000 kg/hour or more, or even 1200 kg/hour)
kl? /mW or more can also be obtained. The crystal length in the molecular chain direction of a cold-stretched product also has a crystal length of 2.
It has an OA of 0OA or more and a birefringence of 25X10 or more.

In addition, even when the molded product is a film, a draft ratio of 300 kg/mrn2 or more can be obtained in the raft direction, and by similarly increasing the draft ratio,
More than 350ky/醋 and even more than 400ky/1! Anything with TR2 or higher is 4'eE. Furthermore, the film obtained by this method exhibits an α-type crystalline structure.

It can be further stretched in the draft direction, and normally transforms into a β-type crystal structure and easily leaks 91F at 500 kg/rnm or more, 600 kg/ram.
You can get even more than that. The crystal length of this stretched film in the molecular button direction is 200A, as in the case of yarn.
and has a birefringence of 25×10 or more. In addition, Young's modulus here refers to a test run of 100y at a tensile speed of 10 mrn/min using Tensilon (tensile testing machine).
This is the initial modulus when the sample of y+m is pulled at 23C.

Moreover, the surface properties of such molded products are compared with those of conventional vinylidene fluoride resin molded products having a large Young's modulus.

It is excellent.

Compare 91 for arts and crafts. FIG. 2 is an electron micrograph of the yarn of the present invention detailed in Section 1, and FIG. 2 is an electron micrograph of the yarn of the present invention detailed in Section 6. There are countless slits parallel to the expected stretching direction, and the surface properties are poor. On the other hand, in the yarn surface of the yarn of the present invention shown in FIG. 2, there are no innumerable streaks as seen in FIG. 1, and it is recognized that the surface property is good.

Furthermore, in the present invention, the term "vinylidene fluoride resin" refers not only to polyvinylidene fluoride homopolymer, but also to a copolymer of 50 mol% or more of vinylidene fluoride and one or more comonomers copolymerizable with it, or It also includes compositions containing at least one of these as a main component.

Examples 1-4. and Comparative Examples 1 to 6 In Examples 1 to 4 and Comparative Examples 3 to 6, a melt indexer manufactured by Toyo Seiki Co., Ltd. (the outline is shown in FIG. 3) was used, and the diameter was 1 mm.
φ, extrusion amount from nozzle 3 with a thickness of 3 mm: 0.63 'j
/min, a pellet of polyvinylidene fluoride homopolymer with ηinh of 1.1 di/g was extruded. After extrusion, it was passed through a guide 90-rule 4 set at about 80 c1rL directly below the nozzle 6, allowed to cool naturally under an ambient temperature of 25C, and wound up with a winding roll 5 having a diameter of 10 cTL. The surface temperature of the take-up roll was 25C. The physical properties of the yarn obtained when the melting temperature and drift rate were variously changed to 4.1ζ shown in Table If 1 using such an apparatus, that is, 23C and paper length of 100 m using a tensile tester manufactured by Toyo Baldwin Co., Ltd.
m, breaking strength when pulled at a tensile speed of 100 zH/min, paper length 100 mm, and tensile speed 10 mm/m
Table 1 shows the initial Young's modulus determined from the stress-strain curve when tensile at in. Furthermore, as Comparative Example 1, a raw yarn made of the same resin as in the example was stretched six times at 160C, and 162C
Yarn tension heat treated at 100C as a comparative example and 4.
The values for the yarn drawn five times are also shown.

Example 5 The yarn obtained in Example 4 was heated in a silicone bath at 150 C.
Young's modulus of 0% stretched yarn is 1460 kg/nnrn
The tensile strength at break was 112 kg/mm. This thread is made of β-type crystal and its crystal length is 420A.
Met. Further, the number refractive index was 42×10 −3 .

Example 6 A device similar to Example 4 was used, except that the nozzle had a variable diameter of 3 mm and a thickness of 3 mm, and the draft rate was changed to 1.
0,800, and other conditions were the same as in Example 4. The Young's modulus of the obtained yarn was 860 kg/myn
The tensile strength at break was 92 kW/+++ m2, the crystal length of this thread was 330 A, and the birefringence was 3.
It was 9×10. Figure 2 shows the surface-F photograph of this thread.
Shown below. Furthermore, this yarn was 21%
Stretched. The Young's modulus of the yarn is 1400 kg/kg,
The breaking strength was 120 kg/mη12. Furthermore, a surface electron micrograph of this thread is shown in FIG. The crystal length at this time is 4
50A, and the birefringence was 41×10.

Example 7 and Comparative Examples 7 to 8 A pellet of polyvinylidene fluoride homopolymer with ηinh of 1.0 dtl has a width of 25.4 mm and a thickness of 0.5 mm.
The film was extruded using a small extruder equipped with a mm rectangular die at a resin temperature of 220 C and an extrusion rate of 45 g/min. The extruded film was directly wound up with a pinch roller consisting of two rubber rollers. At this time, bring the pinch roller as close as possible to the die, and make sure that the pinch roller is straight from the tip of the die.
The distance to the point where it was pinched was about 3 Crn. Furthermore, cold air was blown using a commercially available hair dryer set between the tip of the die and the pinch roller.

Further, as Comparative Example 7, a film was obtained by winding up in the same manner as in Example 7 except that the distance between the die tip and the pinch roller was 50 cWL. Table 2 shows the physical properties of the film thus obtained. In addition, the thickness 1 made of the same resin
Comparative Example 8 also shows the physical property values of a film obtained by stretching a 00μ original film 4 times in the uniaxial direction at 100C. However, Young's modulus and tensile strength at break are measured values in the draft or stretching direction.

[Brief explanation of drawings]

Figures 1, 21 and 4 are surface electron micrographs of the yarn of Comparative Example 1, the undrawn yarn of Example 6, and the drawn yarn, respectively, at a magnification of 1000 times, and Figure 3 is a photograph of the yarn of Examples 1 to 4. FIG. 1 is a vertical cross-sectional view of the device implemented in Here, 1: sample, 2: heater, 3: nozzle. 4 +4'+4''Nigaite roll, 5: Take-up roll, 6: Pujinja. (3 others) Figure 1 αI reading of Figure 2 drawing (no change in content Σ Figure 4 Procedural amendments December 1974F) 7.3 Japanese Patent Application No. 150666 June 2, Name of Invention Vinylidene Fluoride Resin Molding 3, Relationship with the Amended Person Case Name of Patent Applicant Kureha Chemical - 1 Industry Co., Ltd. Kasumigaseki Building Mail Bureau P.O. Box No. 49 Bow 7 Appropriate drawing to be amended (Fig. 6) 3. Details of the amendment Procedural amendment as shown in the attached document Trial date of 1988 Special i' Application No. 160666 Publication 2. Name vinylidene fluoride BFf, 1 molded product 3 Person making the amendment (Relationship with q゛ Name of patent applicant Kureha Kako Dingjo Co., Ltd., branch wholesaler with the same crystal length as 2ooX or more 1- and
3 Eyes closed 11 (Snoring S increases the value of 5XHI or more
What about vinylidene fluoride? fha! , carvings. 2) r-+J Ming's D I'+llll1+j7+',
'j'JJ's crosspiece is 15th Utl (supplement.
E T, Ume-4 Sada Toka, Ra 6 I-chome, 6th page T to 60th; to 2 A], 11th
Added "Crystal 1 ("1-average to σ flying") of the 1st topsoil class of the 1st topsoil class of the 16th mortar. 5th number, ``)νsaJ rl-
"Length" and AIII stop C

Claims (1)

[Claims] A molded vinylene fluoride resin having a crystal length in the molecular chain direction of 200A or more and a birefringence of 25X10 or more.