JPS5861138A - Radiation-bridged tubular body for titration irrigation and composition for extrudable tube - 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 is an extrudable composition that can be formed into a tubular body. ,
Low pressure low density (LP-LD) hydrocarbon copolymer, copolymer of ethylene with Ct-Cs5 monocarzanoic acid vinyl ester and small concentrations of other α-olefins, UV 1! I(U
V) A composition comprising a stabilizer and an antioxidant stabilizer.

Tubular bodies for dripping and dripping are well known. Such tubular bodies are useful for simulating a drip port, for example for watering between fruit trees or for row-planted crops. Since it was invented almost 50 years ago, instillation II* has become popular. Crops grown with dripping produce more fruit and better quality than other irrigation systems.

Generally, the drop forming tubular body has a thickness of about 1 mm to about 561 mm and an outer diameter of about 5 ntm to about 51 fR. Such tubular bodies are typically extruded from a resin composition into single and/or multiple lumen tubular bodies. In general, it is preferred that the resin composition has both extrudability and vacuum dimensional ease. It is also desirable that the tubular body have good flexibility, pressure capacity, and a smooth, shiny surface. The tubular body must also have excellent environmental stress electrical resistance. moreover,
Very useful parameters are pressure capacity and stress cracking resistance.

The dripping II general tubular body according to the prior art is made of high pressure low density polyethylene (HPLDP)-ethylene vinyl acetate (Ev
M) Exceptional blend of copolymer resins.

In particular, ZV mu-HPLDP with gv mu content of about 5%
Copolymer I - 8% gvm content and 10% HDPI
It contained a blend of high density polyethylene (HDPK) 4PLDPle copolymer having a C content and the balance being HPLDP, and LP-LD polyethylene.

However, all of the tubing materials described above have had one or more drawbacks, such as insufficient stress cracking resistance or pressure capacity at elevated temperatures. LP-LD polyethylene provides excellent drop forming tubing, but is more difficult to extrude than other materials. Also, other prior art materials used for the general purpose tubing include rubber-modified HPL
Includes exceptional film products such as D-polyethylene and ethylene-octene-1 copolymer. The latter are difficult to extrude as they have a narrow molecular weight distribution leading to melt failure during extrusion.

In order to eliminate the stress problem by creating a polymer of infinitely large molecular weight, it is known to irradiate a drop-forming tube to crosslink unsaturated bonds within the product. For example, a tubular body was subjected to electron beam irradiation to receive a total dose of 10-11 Mra. Other ingredients present in extrudable compositions typically used in drop forming tubing are UV stabilizers, agents and antioxidant stabilizers. Given that the tubular body is used outdoors and exposed to sunlight.

UV stabilizers are necessary. Carbon black is a common UV stabilizer. Further, during extrusion, it is necessary to contain an antioxidant in order to prevent decomposition of the polymer due to the generation of free radicals.

Here, the following extrudable composition was added dropwise after being crosslinked by irradiation and had excellent bursting strength at 80°C.
It has been found that it produces a tubular body for use. That is.

(1) A low-pressure, low-density, swollen hydrogen copolymer having a weight of about 80 weight cycles or more and about 97 weight cycles or less; (2) a low-pressure, low-density swollen hydrogen copolymer having a weight range of about 2 weight cycles or more and about 10 weight cycles or less.

A copolymer of ethylene and C,-Cs6 monocarboxylic vinyl ester and other α-olefins of low molecular weight and having a density of α21 to l941/cns, (3) Approximately α01 weight ≦ or more and (4) up to about (150% by weight) an anti-clumping stabilizer that allows crosslinking by radiation without destabilization.

LP-LD Hydrocarbon Copolymer The LP-LD hydrocarbon copolymer suitable for the composition for forming a tubular body of the present invention comprises ethylene or butene-1 and one or more cI@α-olefins. This includes copolymers with These copolymers have >cL910~<f:L
? 401/ex", preferably about 281/ass".

These copolymers can be prepared by the 1L tree or gas phase process well known to the 117II trade.

LP-LDjk used in the composition of the present invention! Hydrogenide codeuterium copolymers 1 to #1041/ml m, preferably 11°, have a standard mel index of 5 to about t 2 djl/main.

Extrudable LP-LD used in the extrudable composition of the present invention
Hydrocarbon copolymers are threshold materials, ie solids at wi temperatures. Extrusion grade LP-LD hydrocarbon copolymer tl offsets can also be used in the compositions of the present invention. Therefore, the term "x, p-LDjll hydrogen copolymer"
includes one or more olefins and/or copolymers of the olefin and one or more monomers up to about SOZ.

The examples include ethylene, tetrapyrene, butene-1, isobutylene, pentene-1,4-methylpentene-1, hexene-11 octene-1, nonene-1, de-7-1% unde-7- Included are such as 1% dodecene-1, silidecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1% nonadecene-1 and eicosene.

As a copolymer, one of such olefins is used.
Included are copolymers with one or more other monomers, such as one or more compounds.

Preferred copolymers are ethylene/bupylene copolymers,
Ethylene/butene-1 copolymer, ethylene/isobutylene copolymer, ethylene/benzone-1 copolymer 4, ethylene/4-methylpentene-1 copolymer, ethylene/hexene-1 copolymer, ethylene/octene-1 It is an ethylene copolymer such as 1 copolymer. Preferred ethylene copolymers include two or more of the following: propylene, butene, isobutylene, santhene-1, heno-1,4-methylpentene-1, and octene-1.
wrap around. In addition, preferred butene-1 copolymers include ethylene, propylene, hemium-1,4-methylpentene-1,
1 and off'P>-1tt comonomers.

Preferred low pressure MS degree ethylene copolymers for use in the present invention include P. J. Karo1 et al.
Filed on February 51, 1979, tsG filed on February 27, 1979
U.S. 4I Patent Application No. 8 refiled as No. 14,414
22,525 (name: Production of ethylene copolymer in a fluidized bed reactor), Q, L.

No. 892.522 (title: Impregnated Polymerization Catalyst, sl! (use for finishing and ethylene copolymerization)
This includes those that can be produced by the method described in 1. and the method for producing an ethylene hydrocarbon copolymer having the properties described above. U.S. Patent Application No. 014,414 is
This corresponds to ■-P Tsuba Patent Application No. 57t1oopsts, which was published as Public Notice No. 14645 on October 17, 1979, and No. 012,720 was published as Public Notice Section No. 4647 on October 17, 1979. This corresponds to So-P Tsuba Patent Application No. 79100?5&2. The disclosures of these publications 44458 and 46478 are incorporated herein by reference.

Other preferred low pressure paper heptad ethylene hydrogen fluoride polymers for use in the present invention are: 1. It can be produced as described in U.S. Pat. Ethylene vinyl ester copolymers, the disclosure of which is hereby incorporated by reference, are preferred for the present invention. %~〈10% by weight. Other α-olefins can also be present in small amounts in the copolymer. Ethylene vinyl ester copolymer c, about a 91 to # a
The carboxylic acid vinyl ester having a density of 40 is preferably an aliphatic saturated monocarboxylic acid ester, such as vinyl boupionate, vinyl hexanate, vinyl octanoate, vinyl dodecanoate, vinyl behenate or acetic acid. The preferred ester is vinyl acetate at a concentration of about 2% to about 55%, preferably about 25% to 55%.

UV Stabilizer The tube forming composition of the present invention contains at least one UV stabilizer. These UV stabilizers range from about aOt% to about 5%
present at a weight concentration of The UV stabilizer is one that can absorb ultraviolet light more easily than the olefin polymer in the composition or is capable of interacting with and deactivating free fusicals as soon as they form in the composition. .

Preferred UV stabilizers according to the present invention include carpump footer, dipenzo7enone derived intermediate in 2-human W, cyenylpenzotriazole in hydro, and the like. Other UV considered suitable for the present invention
Stabilizers include the following. 2.4-dihydro-benzophenone, 2-human tetraxy-4-methoxybenzophenone, 4-(heptyloxy)-2- and dotetraxybenzophenone, 2-hydroxy-4-(octyloxy)benzophenone, 2-hydroxy-4 -(2-
Benzophenone, 4-alkoxy-2-hydroxybenzophenone 2-hydroxy-4
-Methoxy-5-methylbenzophenone, 5-benzoyl-4-human dibenzoyl-2-methoxybenzenesulfonic acid, 2-(2-dibenzoyl-4-meth) rest IFI! , 4-methoxy-cyaenone in 2'-dihydro, 4-butoxy-2,21-dihydro-Voxybenzophenone and 2-human-dihyde such as 4-(octyloxy)benzophenone in 2,2'-dihydro xybenzophenones j2-(2H-benzotriazole-2
-yl)-p-cresol, 2-4-butyl-6-(5
-Rikuru 2M-benzo)lyazol-2-yl)-p
-Cresol, L4-di-t-butyl-6-(5-riW
2H-benzosiliazol-2-yl)phenol and 2-(2H-penzotriazol-2-yl)-4
6-G is one pentylphenol, 5-2-(2H-
benzotriazol-2-yl) phenol I [I salicylic acid 7 el, nalicylic acid p-($%翫5-tethomethylbutyl) 7 el, resorcin monobenzoate,
7-El esters such as bis(p-nonyl 7EL) terephthalate and bis(p-LL & 5-tetramethylbutyl) 7EL Isophthalate ibis(2,2'-thiobis-4-(t1145-tetramethylbutyl) ) phenoxy] nickel and (2,2'-thiobis(4-(tt
L! -tetramethylbutyl)phenol)7)(2-)
) butylamine) nickel compounds such as nickel.

Antioxidant Stabilizer The tube forming composition of the present invention contains at least one antioxidant for the olefin polymer.

These antioxidants are present in a stabilizing effective amount.

Such amount is approximately (10
02~α5. Preferably, the weight range is about (105 to α12). Antioxidant stabilizers that can be used in the compositions of the present invention include polyolein stabilizers commonly used in olefin polymer-based tubular extrusion compositions. All of the antioxidants are mentioned. These materials include e.g.
Such that it can provide antioxidant protection at processing temperatures of the order of 5° C. to 54 S”C or higher.

Such antioxidant stabilizers include t-butylene diphenylcyclohexane, di-p-hydroxyphenylcyclohexane, t-butylcyclohexane, t-butylcyclohexane,
-Cresol, 2.6-di-butyl--cresol, λ46-tri-t-butylphenol,! -(45
-di-t-butyl-4-trixphenyl) tetrapionic acid octadecy I%I, tetrabis[methylene 5-(s
'es'-17-4-butyl-4'-human diphenyl) tetrabionate] methane, t45-) listyl-2
,4,4-)Lis(翫5-di-t-butyl-4-human-oxybenzyl)benzene, Tris(45-di-1-butyl-4-and-doxybenzyl)isocyanate, t4
5-) Lis(4-t-butyl-5-human ax-2,6
-Simethylpencil)-$45-)Ryazine-2,46
-(I Hy 5 H #5M) trion, bis [to 3-
Bis-4-1 and de-affected C-s'-t-butylphenyl)
Butane #) tallycol ester, bond formation between phenol and formaldehyde, reaction product between phenol and methylene 1tl-methylenebis(4-human tetraxy-to-5-1-butylphenol).

2.21-methylenebis(4-methyl-4-t-butylphenol), 2.4-(2-t-butyl-4-methy5
t-6-methylphenyl)-decresol, phenylethyl bitetracatechol, 7-ethyl isog gastric pilpi aj1
Tecol, tL5-)lis(21-methyl-5'-t'
-butyl-4-human diphenyl)butane in W, 2.2-
Methylenebis[6-(α-methylshitahexyl)-4
-methylphenol], 5-tramethyl-2,4,
4-) Lis(S'e5'-di-t-butyl-4-human tetraxybenzyl)benzene and 111F phenol s z 2 +-thiobis(4-
Methyl-4vt-butylphenol), 44'-thiobis(3-methyl-4-t-butyl7el).

Sulfur-containing compounds such as distearylthiodibuta, dilaurylthiodiglobione, polymerized t2-dihyde-2,2,4-)samethylquinoline, and 6-ethylquinoline.
2-dihydro-2,2,4-)limethylquinone and 6
Examples include quinoline compounds such as -dozosyl-t2-dihydro-2,2,4-)limethyl-monoline.

Preferred primary anti-saponification stabilizers used in the compositions of the present invention are the five quinoline compounds mentioned above. These allow crosslinking by radiation and still act as thermal stabilizers.

Primary quinoline antioxidants can be used separately or in various combinations Other additives The composition of the present invention is a combination of LP-LD hydrocarbon copolymer 1 ethylene and C1-CIO monocarboxylic acid vinyl ester. In addition to the polymer, UV stabilizers and secondary antioxidants, other adjuvants commonly used in olefin polymer-based tubular extrudable compositions can be included. Such other adjuvants include fillers, pigments, lubricants, modifiers, and similar materials.

Fillers that can be used in the olefin polymer-based extrudable compositions of the present invention are those commonly used with such polymers. The filler is used in an amount equivalent to about 1 to 20 weights based on the weight of the olefin polymer. Such fillers include materials such as titanium dioxide, clay, diatomaceous earth, diatomaceous earth, and other materials known in the art.

The lubricants commonly used in extrudable compositions based on olefin polymers are those commonly used with such polymers. The lubricant is used in an amount corresponding to about an α02 to α5 weight range of lubricant based on the amount of olefin polymer. Examples of such lubricants are fatty acid amides such as stearamide, oleamide, pehenamide and lauramide. Other lubricants include salts of calcium, zinc, titanium and Group 1 or Group I metals of stearate. Preparation of Extrudable Compositions Extrudable compositions may be prepared by a number of methods well known to those skilled in the art. I can do it. One method is that the components are p
In another method, the ingredients are blended using a Banbury batch mixer combined with a 7-allele bar and 5-screw extruder and melt pump. The ingredients are mixed in a Banbury mixer for about 1 to 5 minutes, and then mixed at a temperature of about 25℃ to about 185℃.
The extruder is extruded from the extruder melt pump using a barrel temperature of about 175°C and a die temperature of about 175°C.

In yet another method, the ingredients are compounded in a Banbury integrated batch mixer, fed in melt to a -screw extruder, and pelletized under water. That is, the ingredients are
Banbarimi I? The resin is mixed for about 15 to 5 minutes in a mixer, usually using three cycles, two cycles separated by a short non-processing cycle that only cuts the resin. It is then cooled at a temperature of about 50°C to about 190°C and extruded through an extruder using a barrel temperature of about 180°C. At the end of the extruder is a perforated die plate where rapidly rotating blades cut the extrudate passing through the die plate to form pellets. These pellets are then used to extrude tubular bodies.

The equipment used to form drop-forming tubular bodies from the compositions described above basically varies in length from a length/diameter (L/D) ratio of 16 to 1 to a length/diameter (L/D) ratio of 52 to 1. D ratio and consists of a standard extruder that can take any diameter required depending on the desired production rate as is well known in the art. The extruder must be equipped with some form of Archimedean screw, whether a barrier type, such as a Madotsuda mixing screw, or a standard conventional type. However, a zigzag mixing screw is the preferred screw. In addition, the extruder can be used at temperatures ranging from 125°C to 280°C.
It should be possible to set the temperature steplessly in degrees Celsius and have barrel cooling capacity.

The polymer is fed into the extruder in pellet form and is melted by a hot barrel and shear forces (i.e., mechanical dissipation in the form of heat from the screw) to melt it and deliver it in a molten state to a die. .

In the method for forming a tubular body for the surface of a tubular body by extrusion of a profile, a polymeric tubular body molding composition is melted and then extruded through an annular die. The die is about α25111m or more and about &Q 11
less than 1 m11, preferably more than about uso'tssm
Has a die gap of 90 grooves m or less. The polymeric tubular molding composition is extruded at a melt temperature of about 50 DEG C. to about 240 DEG C. The extrusion is carried out in an annular configuration in a horizontal or downward direction. The annular extrudate is usually drawn down to the desired dimensions;
It is then cooled in a vacuum sized tank with water inside. The annular extrudate is generally drawn down to the desired dimensions by vacuum sizing methods, techniques well known to those skilled in the art.

This technique uses a vacuum sizing sleeve to size the tubular body. This sleeve was in the bath,
It cools and assimilates the tubular body into its proper shape.

The tubular body is then drawn off at a constant speed by a multi-contact drawing device and then wound onto rolls for rinsing. A multi-contact pulling device provides the necessary tension to provide the desired wall thickness. This is also well known in the art.

While the inside of the tubular body normally remains exposed to atmospheric pressure, the outside of the tubular wall has negative pressure due to the vacuum sizing method, so the tubular body is pulled against the vacuum sizing sleeve. , which gives its final shape.

The drawdown ratio at the outer diameter, defined as the inner diameter of the bushing divided by the outer diameter of the final tubular body, should be less than or equal to 2 to 1. The wall thickness drawdown ratio, defined as the die gap divided by the thinnest wall thickness of the final tubular body, should be no greater than 15 to 1 for a good quality tubular body. In some cases, the tubing can be perforated, for example by exposure to a laser beam, and then irradiated to crosslink the polymeric tubing.

Physical Properties of Drip Layer Tubes As previously mentioned, physical properties of particular significance for the successful use of thermoset drip layer tubing include stress cracking resistance and fracture resistance, particularly at elevated temperatures. It is % characteristic. For the latter, the bursting properties at 80°C are particularly important. Excellent environmental stress cracking resistance (E8CR) and II-temperature and 8
Tubes with failure IN properties at 0° C. are generally very satisfactory for drip shoulder tubular applications worldwide.

The drip irrigation tubing of the present invention was found to have excellent E8CR and improved burst characteristics at 80°C. E8CR
This prevents the tubular body from breaking in the field when subjected to other mechanical stress due to insertion fittings or from sharp pinching of the tubular body. This JI is used to tighten tubular bodies together.
The method commonly practiced in JI is to fit the tubular body into a barbed joint.

The dripping filament is usually installed on the ground in arid or semi-arid regions, where the temperature of the tubular body is rather high in the summer, for example up to about 80.degree. Since the inside of the tubular body is still under pressure, the tubular body must have a pressure-bearing capacity at 80°C. The internal pressure is created by water in the pipes being metered out by the individual pumps.

Usually, the drip rinsing tubular body is a double chamber tube having a main chamber and a small chamber. The main chamber portion of the tube maintains the pressure. Because only a small number of holes are drilled in the chamber portion of the tube, the pressure therein does not substantially decrease. The O drip crushing tube used to meter the water into the pressure cover 7' in the chamber must have a very good bursting strength or bursting stress. This is measured as the hoop stress, which is the actual stress in the wall of the tubular body, and is calculated by multiplying the outer diameter of the tubular body minus the wall thickness by the pressure, which is the actual stress in the wall thickness.
Defined as divided by times the value. a certain 7
- Dripping tubing formulations that no longer exhibit breakage times under stress are generally presented as better materials for this particular application at a given humidity. Dripping thirst faJ
Since the 4I tubular body is exposed to high temperatures only during the extremely hot part of the day (part of the day, i.e. during the period of use), the bursting properties of the tubular body at 80°C are improved even for a few hours. This corresponds to more than a few days of use. Regarding the tubular body for the dripping shoulder of the present invention, the bursting strength characteristics are as follows:
No breakage was obtained after about 500 hours at a 7-p stress of 400 pal. 40 at 80℃
A tubular body having a failure time equal to or greater than the SOO time at a 7-p stress of G pal is generally considered to be a good tubular body. The drip crushing tube of the present invention not only achieves the aforementioned maximum requirements for burst strength properties, but in fact far exceeds such maximum requirements.

Crosslinking of extruded tubular bodies Crosslinking of extruded tubular bodies can be accomplished by a variety of methods, including, but not limited to, ionizing and non-ionizing radiation, and chemical bonding by covalent, ionic, and other types of bonding. Contains crosslinking.

One chemical crosslinking method consists of contacting the extruded tubing with a crosslinking agent in the presence of a free radical catalyst. Examples of the crosslinking agent include compounds such as 1,4-butylene dalycol diacrylate, tesira ethylene glycol diacrylate, polyethylene glycol diacrylate, and methylene bisacrylamide. Typical free radical catalysts are azoisobutyrinitrile, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and the like. Besides free radical catalyzed chemical crosslinking, other methods can also be used. These methods are well known to those skilled in the art and include the use of peroxide catalysts. ionizing radiation. As used herein, the term "ionizing radiation" means radiation having sufficient energy to cause electronic excitation and/or ionization in polymer molecules, but not enough energy to affect the behavior of the constituent atoms. No radiation means. Preferred convenient sources of ionizing radiation include r-ray producing radioisotopes such as C@@Oβ(m 11 Y), waste nuclear fuel elements, X-rays such as those produced by conventional X-ray machines, Fundaday 7 accelerators, linear Electrons generated by means such as electron accelerators, resonant transducers, etc. Ionizing radiation suitable for use in the present invention is
Generally, it has energy levels ranging from about α05 M@V to about 20 M@V.

Irradiation of the uncrosslinked lid assembly can be carried out in air, vacuum, or various gaseous atmospheres. Any conventional method for contacting the polymer with ionizing radiation can be used. Preferred methods are known and readily understood by those skilled in the art.

The following examples are illustrative of the invention and are not intended to limit its scope.

Example 1 Production of polymer resin Low-pressure low-density ethylene-butene-1 copolymer is made of W, Mu,
South African Civil Patent Publication No. 79-01 of Mr. Fras*r et al.
The properties of the 0-ethylene-butene-1 copolymer produced by the method disclosed in No. 365 (published on September 22, 1980, name: Process for producing films from low-density ethylene hydrocarbon copolymers) are as follows. 〇 density determined by ABTM D-1505
The disc sample that was slowly cooled (15°C/min) was
2B, prepared according to condition C. Density is 9/cps'
Record as.

Melt index (Ml) is ABTM D-12
18, determined according to condition E. It is 190℃ and 30℃
Measured at 5 kPa and recorded as jF/10m1m.

The flow index (HLMI) is ABTM D
-1258, measured under condition F. That's SOS
Measured in OkPa and recorded as #/10m1m.

Melt 7 Reh ratio (MFR) was calculated as 70-index/melt index.

- The binding modulus was determined using Mu8TMD-8512.

Stress crack resistance was measured by the following method. 7 tube samples
It was aged for 4 hours at 0°C, then inserted into a protruding fixture with a strain of 15≦, and placed in a 10 volume aqueous solution of 41/l of ethylene oxide at 50°C.

Yield strength, elongation rate and tensile strength at break are ABTM
D-1928, measurements were made on ivy compression molded disk samples according to conditions CGC. Properties were tested by A8TMD-658.

Long-term burst properties were tested by Mu19TMD-1598.

Short-term breakthrough l&! The characteristics (rupture between 11 and 11) are as follows: Mu8TMD-1
599.

To test the crosslinking rate ≦ after irradiation, the crosslinked polymer is heated to boiling decalin. 0, consisting of soaking and then measuring the amount of extraction.
The remaining part is considered to be the crosslinked part.

Thus, the ethylene-butene-1 copolymer had the following properties: melt index of α55, MFR of 65, and compound density of 0.920.

Ethylene vinyl acetate copolymer was used. This copolymer had a vinyl acetate content of 28% and a melt index of 575. Additionally, polymerized 12-dihydro-2,2,2-)limethylquinoline, which is a carboxylic acid and an antioxidant, was also used.

Preparation of Extrudable Compositions The following compositions were compounded using a Banbury miller and dropped as a melt into an extrusion hopper for feeding into an extruder as described above. Three extrudable compositions were prepared and the esthetic properties of these compositions are summarized in the table below.
Shown below.

Table ■ Composition LPLDPIC (vt%) 87.4 82.4 9
2.4EVA (vt%) an 1 (LQ density E
llZbl&”) α9388 α937
8 α9386 tensile strength (psiXlo)
2-96 2.75 2.76 Yield strength (p
siXlo) t59 t42
t69 elongation at break (%) 858 8
08 726* The masterbatch consisted of the following composition. Melt index of α2 and α921
Tubular reaction 1 HPLDPE with density of 65% and 451
Carbon black 55 with the maximum particle size of Wi.

The extrudable composition was extruded using the profile extrusion method described below.

The produced beret products! (NRM) 2.5 in. 16 with docked mixing screw, barrel cooling means and stepless temperature control from 125°C to >500"°C
The extruder was fed into the hopper of an extruder with a L/D ratio of 193°C, 199°C and 20°C, respectively.
Three barrel zones at 4℃, one extrusion head at 204℃'! and one die zone of 204°C. The extruder screw rotates at 45 RPM to approximately 324 rpm.
hr production rate 1. y:. The molten polymer was then fed directly to a through spider tape die to form an annular extrudate. The inner diameter of the die was approximately s 1 mm, while the outer diameter of the bottle was approximately 25 mm in diameter. The resulting extrudate was then drawn down using a vacuum sizing method to approximately 1718 beak outside diameter and approximately 15 mm ID@thickness. The vacuum sizing tank was equipped with a brass sizing sleeve having a length of approximately 5TM diameter of the N tubular body. The sleeve was perforated to allow a vacuum to create a negative pressure to draw the extrudate into the sleeve. Cold water fixes the extrudate to this diameter @vacuum sizing tank used a vacuum of 2-6 isHI. The tank was 6 ft long with a multi-contact drawer lid arrangement to pull the extrudate at a constant speed and produce a constant wall thickness. The tubular bodies were tested with a delay of at least 2 days ◇ The 5fa composition shown in Table ■ was extruded into tubular bodies as described above, counter pressure tested before and after 10 Mrad IDWi injection, and stress cracking resistance as well as short term and I! It was tested for period bursting strength. The results are summarized in the table below.

Table I Instant burst strength (psi) before irradiation 157s
1550 1795 Instant burst strength after irradiation (pli)
1800 1745 1850 Long-term pressure test at 80℃ (kr) 400 psl before irradiation 216 12
4 After 125 irradiation 4001*Amount >561
2 >128 2824 irradiation key 520 psl
) 320B > 1840 52 after 4760 irradiation
0 pal >8008 >5485 6
696 Crosslinking rate after irradiation (%) 57
56 4B No Appreciable Damage J Table 1 below summarizes the extrusion equipment conditions.

Table ■ Band 1 (”C) 193 195 1
952(”C) 199 19
? 1993 (“C) 20
4 204 204 head (”C)
204 204 204 die (”
C) 204 204 204 Material temperature ("C) 200 1515
200 amps 110
1α6 1α6 RPM
45 45 45 head pressure (psi)
1000 975 1100 Speed ('?/
hr) 52,6 52.5 52
．． 6ゝGo'/

Claims (1)

[Scope of Claims] (1) (a) A low-pressure, low-density hydrocarbon copolymer having a weight ratio of about 80 or more and a weight of about 97 or less.佽) Approximately 2 weight or more and approximately 10f [ff11 or less. A copolymer of ethylene and C1-Cs* (F-nocallic acid vinyl ester and a small concentration of other α-olefins, with a density of α91~(L?4#/m”). an ultraviolet light stabilizer having a weight of about 101 or more and not more than about 3 by weight, and (d) a non-destabilizing (antioxidant stabilizer capable of crosslinking by radiation) about aSO by weight or less. An extrudable composition suitable for forming a tubular body by extrusion. Polymer or ethylene-octene
1. The composition according to claim 1, comprising one copolymer or a combination thereof. (3) Ethylene vinyl ester copolymer is #2s~
Claim 1 consisting of an ethylene vinyl acetate copolymer having a vinyl acetate content of 55% by weight! fill! Composition of item 1. (4) The composition according to claim 1, wherein the ultraviolet stabilizer is carbon black having a particle size of 1◎Oμ or less. (5) Extruding the extrudable composition into a tubular shape in a single-screw extruder with a barrel temperature of about 150°C to 240°C, and electron beaming the extruded tubular body to receive a total dose of about aOS to about 40 Mrad. Approximately 1 by subjecting to irradiation
1 mm to about 581 vortex thickness and about smm to about 51
In producing a thermosetting tubular body having an outer diameter of mm,
As an extrudable composition. ←) A low-pressure, low-density hydrocarbon copolymer with a weight ratio of about 80 or more and less than about 97. A copolymer of vinyl phosphate and a small concentration of other α-olefins, with α9
(c) an ultraviolet light stabilizer having a density of about (L(M) by weight or more and about 5 by weight), and (d) about (L(L)) having a density of about a composition consisting essentially of a low pressure low density polyethylene having a melt index of about a55, a compound density of about a950 and a melt ratio of about 65. 7 than the extruder head pressure required to extrude the product
11-A method for producing a thermosetting tubular body, characterized by operating at a low extruder head pressure. (6) Manufactured by the method described in claim 5 and having a 7-pressure stress of 400 psi at 80°C of about 36
Over 12 hours! Approximately 8008 at 20 pml hoop stress
A cross-linked thermosetting tubular body for drip-forming parts that has a bursting strength of more than 3 hours.