JPS5964339A - Oriented polymer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coordinated polymer having physical properties (hereinafter referred to as a coordinated polymer).

Methods for producing solid-state deformation of polymers 7 are well known. For example, when a polymer is extruded from a die at a temperature below one melting point using a piston or ram sliding in a cylinder, an extruded product having a certain degree of orientation is obtained. This arrangement will improve the mechanical properties of the extrudate. More uniform orientation can be obtained by isostatic extrusion, in which case the polymer is forced to flow through a die under hydrostatic pressure at a temperature below its melting point.

However, it is known that these methods have limitations in improving the mechanical properties of polymers.

However, it has been found that selecting starting materials with high natural draw ratios results in polymers with significantly improved physical properties.

The present invention provides a routable polymer material film having improved physical properties by subjecting a routable polymer having a natural stretch ratio of 6 or more to solid diamond treatment.

As used herein, the term "solid deformation" means deformation of a polymer under pressure at a temperature below its melting point, and includes treatments such as extrusion and rolling. However, since it is particularly preferable to apply isostatic extrusion, the following explanation will be limited to this for convenience, but it is of course understood that other molding methods, such as piston, ram, and rolling, may also be employed. It should be.

Non-invention also requires a minimum outer dimension of 0.25 mm or more and a Young's modulus of 3.
All drawn high-density polyethylene objects with a diameter of ×101 ON/η72 or more are supplied.

The present invention further provides a minimum outer dimension of 025 or more, Young's modulus]×]0
A stretched polyoxymethylene body of 1 ON/m2 or more is provided.

The invention is applicable to all semicrystalline polymers in which molecular orientation is induced by solid-state deformation.

Substantially linear polymer, i.e. 1 in 1000 polymer units
Polymers with no more than three branches are preferred. Particularly good results are obtained with high-density polyethylene.

(Hereinafter, in the margins) Herein, areal density polyethylene is defined as "a substantially linear ethylene homopolymer or copolymer containing at least 95% ethylene and having a density of 0.
85-1. OQ /cyn3ノalso'7-)(Example tha,
A sample prepared according to Prittisch Stantat Subification A, 3412 (1,966), as well as one prepared by polymerizing ethylene in the presence of a transition metal catalyst, was also prepared by Prittisch Stantat Subification A, 3412 (1,966). &, 2.782 (1970)).

The natural stretch ratio of a polymer can be defined as either the ratio of the longest length obtained by freely stretching the sample to its initial length, or the ratio of the cross-sectional area of the sample before and after stretching. For high-density polyethylene, for example, sample at 75°C19
0 second bend, Instron tension at a rate of 10 α/min: Determined by stretching on a testing machine. The natural stretch ratio of a polymer depends on its weight (hereinafter margin) average molecular weight W, number average molecular weight in and initial morphology.

The weight average molecular weight of the polymer is preferably 200.000
Below, most preferably 50,000 to 150,000-
The number average molecular weight is preferably 20,000 or less, most preferably 5.000 to 15.000. Furthermore, the polymer has a relatively narrow molecular ■ distribution and M n ) l
When Q4, Mw/Mn is 8 or less, preferably 6 or less, and when -Mn is 104, Ww/Mn is 20 or less, preferably 15 or less.

In practice, the weight average molecular weight is 10. lX104, IJ Zydex 50 (Rigide) with number average molecular weight 6-2x103
Excellent effects can be obtained by using x 5 Q; polyethylene polymer manufactured by B.P.PHI. Chemicals Ltd.). Note that the molecular weights cited herein are those measured by gel permeation chromatography.

For high density polyethylene - preferred polymers are those with melt flow values of 01 to 16 - especially 25 to 7.5.

The morphology of the polymer also affects the natural draw ratio, and polymers having substantially constant morphology across the cross section are preferred. However, for billets used in isostatic extrusion that have relatively thick cross-sections, it is impossible to sufficiently improve the morphology by changing the rate at which the polymer is cooled from the molten state. The cooling rate generally depends on the thickness of the material and the thermal conductivity of the polymer, and can often be as slow as 01-b minutes. Cooling at faster rates generally results in an undesirable non-uniform crystal structure across the cross section. It is preferable to cool the molten polymer at a normal cooling rate depending on the surrounding conditions and select an appropriate molecular weight to obtain a uniform crystal structure. Methods for producing polymers with high natural draw ratios suitable for use in the present invention include, for example, compression molding-melt casting, extrusion, extrusion molding, and the like.

By appropriate selection of molecular weight and heat treatment, very high natural draw ratios can be obtained. Preferably, the natural stretch ratio of the polymer is 10 or more; for example, the natural stretch ratio of high-density polyethylene is 20 or more, and in some cases, a natural stretch ratio of 38 can be obtained.

In accordance with the present invention, a preferred method is to extrude the polymer through an orifice of a die, e.g. under hydrostatic pressure. For example, in the case of rod extrusion, the polymer is The ends of the billet are machined. Pressurized hydraulic fluid is introduced around the billet.
The hydrostatic pressure to extrude the polymer through the die orifice and form the extruded rod is preferably in the range of about 0.2 to 3 kilobars.

It can be seen that the orientation, ie, the physical properties, of the extruded polymer improves with increasing deformation ratio, ie, the ratio of the cross-sectional area before extrusion to the cross-sectional area after extrusion. There is a limit to the deformation ratio that can be obtained. As this limit value is approached, the extrusion speed relative to the applied pressure becomes an impractically low value. Under these conditions, even further increases in pressure would limit the extrusion rate and eventually result in product fragmentation.

The critical rhombic ratio, when the extrusion speed is reduced to an uneconomical value, is related to the natural stretch ratio of isotropic polymers. Deformation ratio up to about 10, depending on the applied polymer 10-2 Fl
) S gives good results.

At low deformation ratios, the extrudate tends to expand after leaving the orifice of the die, limiting the deformation ratio and reducing the degree of orientation. This phenomenon can be reduced by applying a tensile pulling force to the extrudate. This tensile pull-off force is usually at least 0.001 kbar;
It may be considerably greater depending on the tensile strength of the extrudate.

However, when the polymer is extruded above the deformation ratio range of 8 to 10, expansion is normal and no tensile pulling is necessary except for use to keep the extrusion product straight.

The extrusion temperature is determined to a certain extent by the type of polymer used, but is generally within 50° C. of the melting point of the polymer. The extrusion temperature of high density polyethylene ranges from 80°C to the melting point.

The process of the invention makes it possible to produce a structured polymer with physical properties not previously available - in particular it makes it possible to obtain a structured polymer with a very high elongation in one extrusion cross-section.

For example, the method of the present invention has a minimum outer dimension of 2.5 mm or more and a Young's modulus of 3.5 x 101 ON/m? It is possible to produce stretched high-density polyethylene objects having the following properties.

As used herein, Young's modulus is defined as the secant modulus when applied to an extensometer at an elongation rate of 10=-approximate elongation rate of 3X10-3 MIN'' and a temperature of 21C.

The high modulus polyethylene bodies obtained by this invention are usually transparent and can have improved thermal stability at temperatures below -100°C. These can be used as structures and are particularly suitable for making tubular objects.

The Young's modulus of the extruded polymer can be further improved by incorporating particulate or fibrous fillers into the polymer before deformation.

The present invention will be explained in more detail with reference to the following examples.

Example 1 This example is an example of manufacturing a polyethylene rod having a high elongation rate from polyethylene having a high natural draw ratio according to the present invention 4H4y.For comparison, a similar rod was manufactured from polyethylene having a low natural draw ratio. Also indicate if it is manufactured.

Rigidex 50 is a commercially available high density polyethylene with the following physical properties: Density 0.96 Weight average molecular weight 10. lX104 Number average molecular weight 6.2X10” Natural stretch ratio (1
(quenched from 60°C) 10 Tensile modulus (T': xtcntional modulus
us) 1.6X10"N/rrf, (S'F) A billet of this material is compression molded and cooled to room temperature. The specific gravity of the billet after cooling is 0973, and the natural stretch ratio of the polymer is 2.
It is 3. This billet has a semi-angle of 15° and a hole diameter of 2.
．． Isostatically extruded through a die of 54 rmn at a hydrostatic pressure of 1.3+c bar and 100°C. The tensile pulling force is 75N.

A deformation ratio of 16 was obtained, and the degree of orientation of one extruded rod was such that the birefringence was 0.060 - the tensile modulus was 2.7 x 101ON/
nl, which is about 18 times that of an isotropic material.

For comparison, another commercially available high-density polyethylene with the following physical properties: tlostalen OU
This test was repeated using R: Density 094 Weight average molecular weight 3.5-4X106 Number average molecular weight
1.00.000 or less natural stretch ratio
4 Tensile modulus 1.2X108N/i (isotropic) The maximum deformation ratio obtained is 5.0, the birefringence tangent is 0.040, and the tensile modulus is 1.2XIO''N/d. This shows that even if the degree of molecular orientation is achieved, if polyethylene with a natural stretch ratio of 6 or less is used, the rigidity will not be improved.

Example 2 This example illustrates the production of high tensile modulus extrudates from polyethylene polymers and copolymers.

A billet of polymer is melt cast and slowly cooled to room temperature at a rate of 101-10°C/min. This billet l- was prepared by the method described in Example 1 at 100°C under hydrostatic pressure at O,001
Extrude at a rate of cm/min. The results are shown in Table 1. The natural stretch ratio is measured by stretching a sample cut from a sheet cooled from the melt at a rate of approximately 1°C/min.

It can be seen from the above table that the ethylene homopolymer gives very high results in the draw ratio, and the ethylene copolymer Rigidex 2000 gives a low result because it has side chains.

Example 3 This example is an example of producing an extruded product having a high tensile modulus from a polyoxymethylene polymer.

Two types of polymethylene homopolymers, Delrin (1) e
lrin) 500 and Delrin 150 (both Du.
(manufactured by Bonn) was compression molded into a rod shape at 200°C and cooled at a rate of approximately 1°C/min. Furthermore, this rod is made into a billet using equipment,
Extrude at 163° C. under hydrostatic pressure.

The extrusion speed was 0.025 cm/min, and the die hole diameter was 1. , 8
The mrb semi-angle is 15°. The results are shown in Table 2.

Specific embodiments falling within the technical scope of the present invention will be illustrated below.

1. A method for producing an oriented polymer, which comprises subjecting an orientable polymer having a natural stretch ratio of 1.6" to a solid-state deformation treatment.

2. Solid-state deformation treatment is carried out by isostatic extrusion” - Note 1
Method described.

3. The method according to 1 or 2 above, wherein the BoIJmer is a substantially linear polymer.

4. Using a vinyl polymer as the polymer” - note 1
The method described in ~3.

5. The method described in 1 to 4 above, wherein high density polyethylene is used as the polymer.

6. The method described in 1 to 4 above, wherein polyoxymethylene is used as the polymer. ' 7 The polymer has a weight average molecular weight of 5o·ooO~150.
7. The method according to any one of the above items 1 to 6, wherein

8 The polymer has a number average molecular weight of 5.000 to 15.000
8. The method described in 1 to 7 above.

9. When the specific force (M n ) of the weight average molecular weight Fz to the number average molecular weight (Mn) of the polymer is 104, Mw
/ Mn 5 or less, MW/Mn when Mn<104
15 or less, the method described in 7 to 8 above.

10. The method according to 5 or 6 above, wherein the polymer has a melt flow value of 01 to 16.

11. The method according to any one of 1 to 10 above, wherein the polymer has a substantially constant morphology across the cross section.

12. The method described in 1 to 11 above, wherein the polymer is heated to a temperature above one melting point before forming into a solid rhombus, and then cooled.

13. The method according to 12 above, wherein the polymer is produced by compression molding, melt casting, extrusion or extrusion molding.

14 1 to 1 above, wherein the polymer has a natural stretch ratio of 10 or more
13. The method described in 13.

15 polymer under hydrostatic pressure of 02 to 30 kbar,
1 to 1 above extruded through a die or IJ
The method described in 4.

16. The method according to any one of 1 to 15 above, wherein the polymer is deformed to give a deformation ratio of 10 to 25.

17. A method as described in 1 to 16 above, which is operated substantially as described in Example 1.

18 Fruit! 1. The method of claims 1 to 16 above, operated as described in Examples 2 or 3.

19. A method for producing an oriented polymer substantially as described in 19.

20 A coordinating polymer produced by the methods 1 to 19 above.

0 21, minimum outer dimension 0.25 mm or more, Young's modulus 3X1 (
IN/m? A stretched high-density polyethylene object comprising:

22 Polyethylene has a weight average molecular weight of so and oo.

22. The polyethylene object of claim 21 above, having a molecular weight of 150,000 to 150,000.

23 Polyethylene has a number average molecule its, ooo ~ 1
5.000.

24. The polyethylene object according to any one of 21 to 23 above, which has a number average molecular weight m (Mn) of polyethylene of 15 or less.

25 Melt flow index of polyethylene 0
．． 1-16, the polyethylene object described in 21-24 above.

26 Minimum outer dimension 2.5 mm or more, YAG ratio 3. Mowing 0
26. The polyethylene object according to any one of 21 to 25 above, having a power of 1 ON/d or more.

27. Actually, wages - Polyethylene objects that fall under the above.

28. Stretched polyoxymethylene object having an f&minor outer dimension of 0.25 mmR and a tar/reflection rate of IXI 01ON/tri or more.

29 Polyoxymethylene objects substantially as described above.

Patent applicant: National Research Development Corporation 228-

Claims (1)

[Claims] ], A high-density polyethylene stretched product having a Young's modulus of 3×10 1 ON/g or more obtained by extrusion in a solid phase. 2.I x 101ON/d obtained by extrusion in solid phase
A stretched polyoxymethylene body having a Young's modulus of the above.