JPS60236724A - Tubular blank - 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 Field of Industrial Application The present invention is applied to tubular materials.
s). More particularly, the present invention relates to a process for deforming tubular blanks containing stretchable thermoplastic polymers and the stretched tubular blanks produced by the process.

Conventional technology Patent Mizumoto's earlier patent (GB 2060469B) includes:
Feeding a substantially unstretched polymer to the inlet side of the die, applying a tensile stress to the workpiece from the outlet side of the die that is insufficient to cause tensile failure of the workpiece, and stretching the workpiece through the die. A method for solid-state deformation of an extensible thermoplastic polymer-containing workpiece is disclosed, comprising progressively increasing its plastic strain by 1jO during start-up of the process. It is an object of the present invention to provide a stretched tubular mill with improved mechanical properties, especially mechanical properties in directions other than the longitudinal direction.

That is, according to the present invention, (1) a hollow 7JD workpiece containing a stretchable thermoplastic polymer is fed from the inlet side of the die;
1) Hollow workpiece sent to the exit side of the die [Although the flea that causes tensile failure of the workpiece is insufficient, the workpiece is fixed at the die and the initial stage of the workpiece. A tensile stress sufficient to reduce the bulk cross-sectional area of the workpiece by simultaneously stretching and deforming six formers disposed inside the workpiece and having a cross-sectional area larger than the internal cross-sectional area. In addition, there is provided a method for deforming a hollow jab containing a stretchable thermoplastic polymer, comprising the step of (iii) recovering the stretch deformed hollow jab from the outlet side of a die.

The "bulk cross-sectional area" of a hollow workpiece means the bulk area of the workpiece in a direction substantially perpendicular to the longitudinal direction; It means the hollow area inside the workpiece in the direction across the upper plane. For example, the external 1 Wt.

So, for a tubular workpiece with lumen diameter or DI3, the bulk is -
υ (ゐ6゜ B The method of the present invention provides for a hollow workpiece having a cross-sectional area (preferably the same tA cross-sectional area) at least as large as the initial internal cross-sectional area of the hollow workpiece, and optionally downstream of the die. This is done by using a former placed inside the workpiece.The cross-sectional area of the former is preferably larger than the initial cross-sectional area of the hollow workpiece, since the cross-sectional area gradually increases. Advantageously, this is done using a former that increases in number.

As used herein, the term "hollow 1JO workpiece" includes tubes and cross sections that are hollow
ck) is included. This includes 11 μm billet and other longer forms of stock. In practice, continuous stocks that may be formed when carrying out the process may be utilized. These include open-ended workpieces having a substantially constant cross-section and preferably having an axis of symmetry. Examples include hollow workpieces whose cross section is circular, oval, square, rectangular, or triangular.

The stretchable thermoplastic polymer is preferably a 1'-crystalline polymer or a polymer that becomes a semi-crystalline polymer; particularly preferred polymers have sufficient strain hardening properties and a flow rate: h, stress strain rate. It is a polymer that exhibits dependent properties and stabilizes the neck formed under the desired stretching conditions. Preferred examples of such polymers include unsubstituted Tf, mono- or polyhalo-substituted (e.g. chloro- or fluoro-substituted) vinyl polymers, unsubstituted or hydroxy-substituted polyesters, polyamides, polyetherketones, etc. Examples include polyacetal. Suitable polymers include linear homopolymers of ethylene or propylene or linear copolymers with at least one comonomer, vinyl chloride polymers, vinyl fluoride polymers, vinylidene fluoride polymers, PIIB, I'l':EK, Includes homopolyoxymethylene, copolyoxymethylene, and the like.

Polyesters are obtained by the reaction of at least one polyhydric alcohol (suitably a glandular polyalcohol or diol) with at least one polybasic acid (suitably a polycarphonic acid). be. Preferred alcohols are monocyclic or aliphatic polyhydric alcohols, such as cyclohexane dimetatool or ethylene glycol, 1,3-propylene glycol or 1,
These include linear C2-C6 alkylene diols such as 4-butylene glycol (especially ethylene glycol). Preferred acids are aromatic, thy. Alicyclic or aliphatic polybasic acids, such as 0-7 thalic acid, m-phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, C5-naphthalenedicarboxylic acid or C2-dihydroxybenzoic acid (
In particular, mono- or polycarbocyclic aromatic acids such as terephthalic acid). Suitable VJJ polyesters include polyethylene 2,6-naphthalate and polyethylene 1
．． 5-naphthalate, polytetramethylene 1,2-dihydroxybenzoate, polyethylene terephthalate,
Examples include polybutylene terephthalate and copolyesters (especially ethylene terephthalate copolyester 10).

By using the die drawing method according to the present invention, a large puffer ratio, creep resistance, gas permeation resistance, and large dead fault (
To obtain products with high axial thermal conductivity (deadfold) or high axial thermal conductivity, workpieces made of linear homopolymers or copolymers of ethylene are 'tiF'
jx average P amount (Mw) is 1,0 0 0,0 0 0
Hereinafter, "50.000 to 500.0"
0 0, preferably 7 0, 0 0 0 to 4 0 0
．． It is preferable to contain a polymer with a Mw of 150, 000 to 800.
,000, preferably 250.000 to 50
It is desirable to contain 0.000 polymer.

However, the Gouy stretching process according to the invention can be applied to drawable amorphous polymers, such as polymethyl methacrylate or polystyrene hollow bodies, or drawable semi-crystalline ultra-high molecular weight polymers, such as those with a MW of about 3 .0
The forming process may be carried out more advantageously by applying it to a hollow 7J roller made of a linear homopolymer of ethylene, but in this case it is not possible to enhance the above-mentioned properties of the product.

Alternatively, the method 2 of the present invention may be applied to this kind of additive that enhances the above-mentioned properties of the product, in which case it will be less than variant 17.

The hollow nD underbody used in the method of the invention may contain fillers. Useful fibrous fillers include glass, asbestos, metal, carbon and ceramic whiskers, such as those made from silicon carbide. Examples of useful laminar fillers include mica, talc, and graphite flakes. Chalk and black fly ash may also be included.

The suitable content of the filler depends on the properties of the filler, and is usually up to 50% by weight, preferably up to 30% by weight, and especially up to 20% by weight.

The hollow workpiece is in a substantially unstretched state before being deformed.

The term "substantially unstretched state" used in this specification refers to 1
Before carrying out the drawing method of the present invention, the hollow workpiece is formed during its formation, for example, during billet molding or melt extrusion.
Or during any subsequent modeling, for example during machining, slight stretching (including stretching in a semi-molten state)
It means a state that has not been subjected to any other stretching.

If the polymer is not available and used as a hollow workpiece, the workpiece may be formed in a batch or continuous process. In either case, care must be taken to cool the workpiece at an appropriate rate to obtain a defect-free hollow 7JD workpiece.

If the hollow workpieces are to be formed in batches, for example as polymer billets, the following general method is suitable. The polymer is melted in a screw extruder, injected or extruded into a billet mold at a temperature about 30° C. above its melting point, and then cooled under high pressure, or the polymer is melted in the extruder. , injected or extruded into a cold billet mold, then held in an oven (at ambient pressure; temperature below the melting point of the polymer and above the crystallization temperature) for 4 hours, after which the heating source is switched off and allowed to cool in the oven. . The polymer may be injection molded in an air or water cooled billet mold. Preferably, polymer assimilation occurs from the bottom of the mold by gradual dipping of the mold into the cooling fluid to prevent internal voids due to shrinkage. Hollow workpieces may be formed in batch by inserting a mandrel with a suitable cross-section into a mold, usually coaxially. Alternatively, stocks with hollow cross-sections of circular or other shapes may be manufactured continuously by any method known in the art.

When the hollow workpiece is pulled through a former having a cross-sectional area larger than the internal cross-sectional area of the workpiece, a bell-shaped nose is initially formed in the hollow workpiece and stretching begins. This can be done by rotating the hollow workpiece onto the former, by inflating an elastic bag inside the nose area of the hollow workpiece, or by pulling a conical former towards the nose area of the hollow workpiece. It may be formed.

In carrying out the invention, the nose formed in the hollow workpiece is advanced to project through the lip of the gouer and is secured to tensioning means applied from the exit side of the gouer. A suitable arrangement includes a retraction device that grips the nose with a pair of serrated jaws, one end of which is attached to a hypertension cable, the other end of which is adapted to handle a rotational moment or mass. It is connected to an applied winch or load string, which applies stretching tension to the nose. Instead of cables, the pulling device may be equipped with tension transmission means 2 used in the field of metal drawing, including chains, rack and pinion mechanisms, screw mechanisms, hydraulically operated drawing mechanisms, and the like. The take-off device may further include a pair of continuously reversing friction belts, commonly referred to as key tapers (rC:ATli:1ζpILL8" is a registered trademark).

The stretching tension should be of sufficient magnitude to stretch the hollow workpiece through the gouer, but insufficient to cause tensile failure of the product. That is, the stretching tension should be such that no strain at any point G on the product exceeds its breaking stress at the chain point. The best value for stretching tension is the standard LS test! can be easily determined depending on the risk. In the case of strain-hardening sweat polymers, as stretching progresses, the flow stress (flosν 5t
ress ) increases. This makes it possible to apply a larger stretching tension, increasing the plastic strain. This allows the use of larger cross-section workpieces and/or smaller diameter dies, further increasing plastic strain. Koil.

The strained polymer is roughly strengthened by the increase in It is possible to increase the distortion in a Buddhist way.

After passing the same size grippable hollow workpiece through the die, the improperly stretched 11-length portion of the nose of the workpiece is removed and the grippable extended portion is regrasped to apply a larger load. I can even hang it.

For certain polymers, a given combination of temperature, draw rate, and deformation ratio will result in a steady state process. The term "deformation ratio" used in this specification refers to the initial diameter of the hollow workpiece relative to the final cross-sectional area of the product.
means the ratio of cross-sectional areas. These parameters will vary, but for a particular polymer the die/k
A, 廿(nominal/! since the process is not isothermal)
[indicating degree of illumination] and the morphology of the workpiece, and experiment ζ
The desired deformation ratio can then be obtained by varying the stretching speed.

In the case of linear homopolymers and copolymers of ethylene, it is preferable to heat the hollow workpiece to within 60° Cu (cold/JO) below the melting point of the polymer.

It is preferable to heat this type of polymer with Mw of 50,000 to 1-50,000 to 70°C to 100°C, and the polymer with Mw of 300,000 or more to 70°C to Preferably, it is heated to 120°C.

M or 150,000 to s o o, o o o polyp I] In the case of linear homopolymers and copolymers of pyrene, the hollow processed product is heated to 20°C to 170°C, preferably 90°C.
Preferably, the temperature is heated to between 130°C and 130°C. 1t80 for homopolyoxymethylene and copolyoxymethylene
℃-170'C1 Preferably 15(]℃ to 170℃. In the case of vinylidene fluoride polymer, 80℃
~165°C is suitable. 55℃ for polyester
~110°C or 55°C to 120°C is suitable.

The temperature of the polymer may be further reduced by using a heated die and/or a temperature regulating chamber extending downstream. Certain polymers may be heated by deuterium (see European Patent No. 1rlGO084274 and US Patent No. 3364294).

Highly transparent oriented polyester mills are made from stretchable thermoplastic polyester fabrics by reducing dyeing (red).
ucing die') o) 55℃ ~ on the inlet side
By heating the workpiece to 105°C, preferably from 60°C to 90"C, and passing the workpiece through a die in the solid 1" state with a nominal deformation ratio of at least 2:1, preferably at least 3:1. Is the invention based on transformation a law? It may also be prepared in this manner.

If you are willing to sacrifice transparency, reduce the workpiece to 105
℃ thinking 5 example is 110℃ or 115℃'' is 21
It may be heated to 1 F; above this temperature the resulting product is opaque and has a low modulus.

In the present invention [this die drawing method], the drawing speed is set to 1
cm/win, 'a J,+, and in fact, stretching speeds of 5 Q on/#Iin or higher are preferred.

Both the flow end of the deformed hollow workpiece and the downstream end of the stock with the same cross section are brought into contact with a stainless steel hot plate and, after the hot plate is removed, both polymer surfaces are welded. A batch process may be converted into a continuous process by this method. Such welds should be at an angle of 45 degrees or less to the lql+ζ of the stock.

By applying the die drawing method according to the present invention to polymers that exhibit suitable strain hardening and strain rate dependence of flow stress,
The deformation ratio can be at least 64, preferably 10 or more.

According to the method of the present invention, the possible deformation ratio is 4.
:1 (PEEK), 4:1~6:1 (PI!:
'J,'-PvDF and PoIJ7 Mi1-)-7:
1-9: ]-(1'OM) and 8:1-12:
1 (polyolefin), etc.

The invention will be briefly described with reference to the accompanying drawings.

Figure 1 shows the device θ cut in the radial direction along the force direction.
FIG.

FIG. 2 is a detailed side view of the die in a configuration in which at least a portion of the die lumen is recessed.

FIG. 3 is a side view of a hoop made of net and deformed as described in Example 2.

FIG. 4 is a detailed side view of the die with at least a portion of the die lumen in a diverging configuration.

FIG. 5 is a detailed side view of a die with a fixed die lumen configuration.

In FIGS. 2, 4 and 5, at least a portion of the die-former configuration defines a reduced cross-sectional area relative to the flow path of the deformed hollow workpiece.

The illustrated device consists of a reducing die (11) with a half angle of 15° and a maximum reduction ratio (ideal deformation ratio) of 2.68, and an oven (2) located upstream of the die, with a tapered leading edge. Mandrel with f51 oligoposterior edge (4) and night (3)
(diameter 21.'81 nJlr, length 10 cm) is held by a rod (6) (diameter 16 mm) i in the non-tapered die outlet (7) (length 1 cm).

The take-off show (8) is connected to a winch (not shown) downstream of the reducing die.

In the experiment, one end of the extensible thermoplastic polymer hollow workpiece (9) was machined to form a nose, and the workpiece was then held at 100° C. around the mandrel and rod. The machined end is inserted into the oven and maintained at 100° C., protrudes from the outlet of the die, and is gripped with a take-up jaw to apply a load. The load is applied slowly at first so that the plastic strain of the billet increases progressively to cause tensile failure. After the stretching starts, a constant stretching speed can be obtained by applying a constant stretching load.Hereinafter, the present invention will be explained with reference to Examples.

Examples Example 1 Ethylene copolymer (commercial product Ma from Ps Co., Ltd.)
rlcx 47100: 0.7-Cl-1=Cl
-12 groups 71000 C atoms, 1.4- CL13 groups/1
00OC atom, Mw205.500. Mn 18,00
0, M/Mn 11.4) into a billet mold (220°C) with an internal diameter of 3 inches and peeled under pressure at ambient temperature for 15 hours to form a void-free billet (length 700mm) was manufactured.

This billet is drilled with an inner diameter of 25 mm, the outer surface is machined with an outer diameter of 63 mm, and one end of the billet is drilled with an inner diameter of 4 mm.
The nose (length 100 mm) was formed by performing machine M7J loe in which the outer diameter was successively increased to 0 mm and decreased to 52 mm (2 mm). frus conical
to-conical) The half-vertical angle of the valleys on the surface is 7). The resulting hollow billet is attached to the aforementioned device,
The billet was left in a device heated to 100°C for 2 hours to bring it out of thermal equilibrium, and the protruding nose of the billet was gripped by a clamp on the exit side of the die, and the billet (ioo°C) was stretched. Speed 10 #W/sin, tension approx. 4C) OK
Under wt conditions, stretch until the fully stretched polymer changes the position of the clamp.

This process was repeated until material drawn from the bulk of the billet emerged from the exit side of the die. After the final displacement of the clamp, stretching speed 190 my/it+, tension 1
Stretching was resumed under conditions of 400 gwt, and virtually all of the billet was stretched to an outer diameter of 40.5 gw and an inner diameter of 32.2 gwt.
A stretched ethylene copolymer tube with an actual deformation ratio of 5.5 was obtained.

This tube was cut to a length of IOam to make a hoop. When these hoops were deformed in a vertical direction using a vise, it was found that before the hoops were destroyed, the distance between the jaws of the vise was tar, which was approximately 24 mm. Distortion occurred. Even after destruction, the hoop retained its shape, and the cracks did not spread to the inner surface of the hoop.

Even when a portion of the hoop was deformed by adding a net blade one inch away from the center of curvature of the hoop, the inner surface of the hoop did not break and exhibited plastic flow.

More quantitative tests demonstrating the increased ductility of tubes made according to the present invention were conducted as follows.

A flexible comb stopper was inserted into the test tube prepared as described above. The com plug is compressed by two pistons installed axially opposite each other and capable of sliding inside the tube.
child. Using a circumferential scale, the maximum change fls in the circumferential dimension of the tube before destruction was added by 1ll1.

The force applied to the piston was taken as a measure of fracture stress.

The circumferential dimension of the tube before breaking due to the breaking stress 3QMI'a expands by 4.6%, f. British 1st country special πrcB2060
The circumferential dimensions of the same polymer tube prepared as described in No. 469B &
Destroy with a +3iJ i will expand by 13% and 1. Therefore, the tube produced according to the method of the present invention has the beauty [
It exhibits a ductility that is about three times higher than that of tubes prepared according to the method described in the patent specification.

Example 2 A transparent tube made of isotropic amorphous polyethylene terephthalate of a predetermined length (KZO company city (υV product i)
8.5 mm, outer diameter 25mm) was pretreated in a zero-order manner before stretching. This tube was attached as a high pressure air line stopper. θ above hot water at 95°C] In a mold, heat the inner JU part of the duplex and heat it for 10 minutes while it is hot.
The tube was inflated once by introducing air at 0 p, s, i into the tube. The air pressured tube was quenched by immersion in a water bath (ambient temperature). Release the air pressure and saw the formed bubble along its red neck to obtain two tubular billets with bell-shaped ends.

The obtained billet was passed through the mandrel and die shown in Figure 4 (
The frustoconical part of the mandrel [the half-angle for increasing the α diameter from IBmm to 35 mm +JD is 15, and the half-angle of the die is approximately 13'] was attached to a device that had been increased [+ifi]. The billet is heated to 75°C and this lR: (79
The temperature was maintained for 1 hour to achieve thermal equilibrium.

At low drawing speeds (typically 1 cm/min) noisy stick-slip occurs and the resulting duplex has irregular and thick walls (1,2 my+).
Outer diameter 36M). However, the stick-slip disappears when the product is stretched at a stretching speed of 3 Q on / mi.
A transparent and smooth tube (outer diameter 27M) was obtained with n. When the drawn material is wrapped around the mandrel, the tube retains a larger outer diameter when it is rapidly cooled. For example, when the drawing speed is 55 on/min, the outer diameter of the wall is 33 mm.
! A transparent and smooth tube with a power of 5 mW was obtained.

Qualitatively, the stretched product is very strong and does not easily fold. It is not possible to further stretch the longitudinally cut strips at ambient temperature. However, the circumferential strip cannot be stretched almost 100%.

Example 3 Thick wall thickness 2j (~ plastic 11 V C tube (IC
1 company's city 1 loss product Po1yorc BS 3505 cL
7 i 32 inner diameter, 42 outer diameter) was stretched before the following pretreatment.

Metal cylindrical tapered nose (diameter 32 mm, length 30 mm)
Form a bell-shaped end at one end of the tube by moving the cylinder that holds the
A conical section (half apex angle 15°) leading to 4 mm, length 7° was heated to 150°C. The tube is initially at room temperature, but the deformed end receives heat from the heating cylinder. This softens the tube and makes the tapered cylinder 15
anO) Even if it is long, it will be pushed into the tube and the end will expand. Taper the tube for one piece /'I'i), then remove the taper (
This operation can be made more easily by applying tapered fleece and removing the front end of the tube. ) The billet with bell-shaped ends thus formed was heated to 95° C. in an oven and stretched using the mandrel and die apparatus shown in FIG. Use one with a diameter of 60mm and a hole diameter of 42am,
The mandrel used was a cylindrical neck with a diameter of 32 mm and a length of 60 mm, a semivertical angle of 15 θ, a conical extension part, and a length of 5 mm (with a diameter of 58 mm and an η-shaped outer part). Two.

The mandrel is disposed coaxially with the tie at its neck or inside the die, and its conically expanding portion is disposed substantially outside the die and downstream of the die, with its constriction meeting the downstream end of the die. The expanded conical part of the mandrel is arranged so as to be formed between the - and the flow. The tube wall thickness is 5. O
The constriction of the point that shrinks from tnm to 3.7M is deformed P
Adjust and control the vC tube flow. The mandrel was equipped with a hole for a cartridge heater, and when the mandrel was moved, the heater was used to heat the mandrel to 95° C. prior to starting the mandrel. It took 1-2 hours for the billet, oven and mandrel to reach thermal equilibrium. The inside of the billet was greased and slightly smoothed. Next, the expanded end of the billet was grasped and stretched at a stretching speed of 70 an/hin and a stretching force of 3.
The billet was stretched under the condition of 50 kg.

The obtained stretched product had a glossy, uniform, and strong tube shape (outer diameter 61 mm, pore diameter 55 ays).

This deformation corresponds to an expansion of 1.6 x (7,) i in the hoop direction and an elongation of 1.05 x in the longitudinal direction.

According to another aspect of the invention, the deformed hollow workpiece according to the invention may be further processed (for example by slitting and/or rolling into sheet stock).

[Brief explanation of drawings]

FIG. 1 is a schematic side view of the device taken radially along the longitudinal direction. FIG. 2 is a detailed side view of the die with at least a portion of the die lumen converging. FIG. 3 is a side view of a hoop shaped and deformed as described in the Examples. Fig. 4 is a detailed 0 (11) diagram of a die in which at least a portion of the die lumen has a diverging form. Fig. 5 is a detailed tl side view of a die in which the die lumen has a constant form. (1) is reduced song die, [21 is oven, (3
) is the mandrel, (4) is the trailing edge, (5) is the front, (
6) is a rond, (7) is a die exit [1], (8) is a take-off tube, (917 is a hollow processed product, and (10) is a stretched tube.

Claims (1)

[Claims] ],, (11. A stretchable thermoplastic polymer-containing hollow workpiece is supplied from the inlet side of the die, and (II) a hollow workpiece is fed to the exit side of the die. The workpiece has a cross-sectional area larger than the initial internal cross-sectional area of the die and the workpiece, although the content is too large to cause tensile failure of the workpiece. A tensile stress of 7 minutes is applied to reduce the bulk cross-sectional area of the workpiece by simultaneously passing through the former disposed inside the beaten workpiece and deforming the workpiece by stretching. 2. The method according to item 1, wherein the polymer-containing hollow material is a semi-crystalline polymer. 3. 2. The method according to claim 2, wherein is an unsubstituted or hydroxy-substituted vinyl polymer, an unsubstituted or hydroxy-substituted polyester, a polyamide or a polyacetal. 4. The polymer is a linear homopolymer of ethylene or propylene. or a linear copolymer of ethylene or propylene and at least one comonomer. 5. The polymer has an Mw of 50.000 to 500.0000.
] The method according to item 4, wherein the polymer is a linear homopolymer or copolymer of ethylene. 6. The method according to item 5, wherein the hollow processed product is heated to a temperature lower than the melting point of the polymer by 60°C. 7 The polymer has a Mw of 150,000 to 800,000
5. The method according to claim 4, wherein the linear homopolymer or copolymer of propylene is a linear homopolymer or copolymer of propylene. 8. The method according to item 7, wherein the hollow workpiece is heated to 20°C to 170°C. 9. The method according to item 3, wherein the polymer is polyoxymethylene. 10 9th step of heating the hollow workpiece at 80°C to 170°C
The method described in section. 11. The method according to item 3, wherein the polymer is a vinyl fluoride polymer. 12 The first step of heating the hollow pressurized object to 80°C to 165°C
The method described in Section 1. 13. The method according to item 3, wherein the polymer is a polyester. 14. The method according to item 13, wherein the hollow pressurized object is heated to 55°C to 120°C. 15. Items 1 to 1 containing hollow pressurized objects or fillers
The method described in Section 4, Chair 7t. 16. The method according to any one of items 1 to 15, wherein the hollow pressurized material is in a substantially unstretched state before being deformed. 17. The method according to any one of Items 1 to 16, wherein the hollow pressurized object is an open-end stretched product having a substantially constant cross-sectional area. 18. The method according to item 17, in which the hollow power rod has an axis of symmetry. 19. The method according to item 18, wherein the hollow workpiece has a circular, oval, square, rectangular or triangular cross section. 20 A former having a cross-sectional area at least as large as the initial internal cross-sectional area of the hollow pressurized object is disposed in the interior of the hollow pressurized object downstream of the die by the die machining point 1'1\. The method according to any of Item 19. 21. The method according to any one of paragraphs 1 to 20, wherein the die is heated. 22. The method according to paragraphs 1 to 21, wherein the stretched thermoplastic blank is passed through a heated chamber downstream from the die. 23. The first term, the second term, is used to stretch the hollow pressurized material through the die with a solid mesh at a nominal deformation ratio of at least 3:1.
The method described in any of Section 2. 24. The method according to item 23, wherein the stretching speed is 50 cm/min. 25. The method described in either paragraph 23 or 24, which is carried out continuously. 26. A stretch-reinforced polymer material produced by the method according to any one of items 1 to 25.