DE2138222A1 - Process for the production of stretched moldings based on acrylonite - Google Patents

Description

Patent attorneys

Plpl.-Ing. R. BEETZ sen. DIpI-In g. K. LAMPiJECHT

Dr.-Jng. R.BEETZJr,
Munich 22, Steinsdorfsir. 10

034-17.356ρ July 30, 1971

Mitsubishi Rayon Co. Ltd., Tokyo (Japan)

Process for the production of stretched moldings based on acrylonitrile

The invention relates to a process for the production of stretched moldings based on acrylonitrile, the due to its low gas permeability and excellent mechanical properties and especially in the form of foils, tapes, webs, drilling or hoses and containers such as bottles and bowls.

It is known that acrylonitrile polymer or copolymer films for keeping or storing products such as foodstuffs etc. with a tendency to undesirable Changes "useful in the presence of oxygen because these foils have a very low permeability for grass, especially oxygen,

034- (0S28) I-iöHe (6)

109887/1732

ORIGINAL INSPECTED

The production of acrylonitrile polymer films is also known by a method in which the polymer is dissolved in a solvent such as dimethylformamide and the resulting solution is spread in a thin layer so that after evaporation of the solvent a thin polymer film remains. Finally, the stretching of objects that were initially unfairly shaped is known a certain temperature, e.g. the primarily formed Foil contains residual solvent and is swollen Condition is present.

In the production of polymer moldings using solvents, it is now impossible to use the molded object completely free of solvents, how to obtain ZeBo dimethylformamide «, according to the above procedure produced foils can therefore only be used to a limited extent due to the harmful effects of the remaining solvent » In addition, the use of solvents in film production causes increased costs, since the solvent used has to be recovered «For these reasons there is great interest in the Production of acrylonitrile polymer bodies from the Melt or the processing of Acrylnxtrilpolymeren in a sufficiently plastic state, with the addition of solvents to the polymer is avoided.

In general, numerous copolymers of acrylonitrile with alkyl esters of acrylic acid are accessible to melt molding. the permeability of the copolymers for gases is lower, the higher the amount of acrylonitrile units in the copolymers.

109887/1732

The permeability to oxygen of 3 types of xolien, the geiaäii of the invention from copolymers of acrylonitrile Hit liethylacrylate is in the reproduced in the following table. In addition to this, the permeability for oxygen is also used for comparison purposes 5 types of commercially available foils are indicated.

The oxygen permeability of the foil vmrde AiSSLi D 1434-50 gladly ο

PoIi e composition Oxygen-
Permeability ο
χ 1013 cc cm / cm
lake. cid. Ed
4.5
3.0
1.5 according to the
invention Acrylonitrile methyl
-acrylate-copolymer
with acrylonitrile
content of
60 wt. -4>
70 wt. Ii
80 wt. Yi 0.2
2.0
56
over 1000
over 1000 trade
common
t *
Polyacrylonitrile
Vinylidene chloride
-vinyl chloride-co-
polymer (iSalan)
Polyethylene
terephthalate
Polypropylene
Polyethylene

Made by pouring out a solution of polyacrylonitrile ' in dimethylformamide and "drying" the resulting Layer.

109887/1732

Hun are copolymers of acrylonitrile with a Alkyl esters of acrylic acid such as, in particular, methyl or ethyl acrylate for the production of Pormkodies by a melt molding process is used, but this generally involves adding a rubber or blastomer component, to improve mechanical properties, d.ru in particular reduce the brittleness of conventional acrylic copolymers. With such mixtures is now the permeability of the molded bodies produced from the polymer is increased. It is true that you can get this unwanted of the Permeability through suitable selection of the added elastomer component and reduction of the mixing ratio limit in some ways, however, with such mixtures, transparency and weatherability are the ones produced shaped bodies compared to those on their own. articles made from the copolymer.

It goes without saying, and does not require any further explanation, that foils, which are used for wrapping commercial goods should be used, in addition to the protective function for these goods, a high transparency and high gloss should have that give the packaged products an overall attractive appearance good processability in the usual packaging machines is an indispensable precondition for the good usability of the Foils.

Although now the special usability of foils in packaging machines on the respective processing conditions depends, the usability is essentially determined by the mechanical properties of the film, such as strength, Toughness and stiffness determined, the best possible mechanical

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- to properties, such as, in particular, toughness for packaging purposes iia with a view to protecting the too packaged goods as well as to prevent damage the envelope or «, the packaging bag during the "The packaging process is of great importance.

Stretched films are also suitable for special wrapping processes useful, in which a strong shrinkage of the film at high temperature is exploited «

The aim of the invention is a process for the production of stretched outer bodies from synthetic resin with acrylonitrile units as the main component, which has low permeability, attractive appearance and excellent mechanical Properties such as toughness and strength »

The erfindungsgeraäße method developed for this purpose is characterized in that a primary molded article of a copolymer of 55 to 85 percent by "- ^c / i acrylonitrile unit s and 15 to 45 wt _o - ^ς> alkyl acrylate units of at least one of the alkyl esters of acrylic acid, whose alkyl groups have 1 to 4 carbon atoms, in which the alkyl acrylate content can be replaced by at least one other copolymerizable luonomer, with an elongation ratio of at least 1.5 in at least one classification and at a temperature of 65 ⁰ to 16O ⁰ G in the practical absence of solvents for the copolymer is stretched »

The amount of the other with acrylonitrile and alkyl acrylate copolymerizable monomers is less than that of the alkyl ester of acrylic acid and their sum is 15 to 45 Gewo-> o of the copolymer.

The essential features of the invention are figured out the following description will emerge in more detail.

VJ-

As indicated above are various copolymers of. Acrylonitrile with acrylic acid esters of lower alcohols with 1 to 4 carbon atoms, such as ethyl acrylate, can be melt-molded »In particular, copolymers with a low acrylonitrile content are easy to process in the melt» If, however, the acrylonitrile content of the copolymer is less than 55 % , this corresponds to The resulting stretched shaped body no longer fulfills the aim pursued by the invention, not only with regard to gas permeability but also with regard to the mechanical properties and thermal dimensional stability of the said standard body.

If, on the other hand, the acrylonitrile content of the copolymer exceeds 85 grains, the melt processability of the copolymer in the absence of solvents becomes much worse and the production of the primary molded article, such as an uncovered film or web, which is then to be stretched, is due to thermal decomposition or tfelierung of Gopolymeren virtually impossible "copolymers with more than 85 Gfew _e - / i acrylonitrile therefore do not meet the more erfindungsgemäS intended purpose.

It has also been found that half of the acrylic acid alkyl ester portion of the copolymer with acrylonitrile contents within the range defined above can be replaced by another monomer copolymerizable with acrylonitrile and acrylic acid alkyl ester. _s ienn the business

1-9 3387/1732

hold of the other monomer in the copolymer over 45 wt. is, the resulting copolymer is for the achievement of the object of the present invention in view of Appearance and melt processing unsuitable as the copolymer composition then tends to to become inconsistent "

As the number of carbon atoms of the alkyl group of the acrylic acid alkyl ester increases, the melt processability of the copolymer is improved, but the thermal dimensional stability of the molded article is decreased and the oxygen permeability increases. Accordingly, the alkyl group preferably contains 4 or fewer carbon atoms "Preferably, the thermal softening temperature of the primary molded article at 6O ⁰ G or above.

The lionomers, by which the acrylic acid alkyl ester can be replaced up to 1-iäifte, include aromatic vinyl compounds such as styrene, unsaturated esters such as ethyl methacrylate, halogenated vinyl or vinylidene compounds, v / ie vinyl chloride and vinylidene chloride, gyanide, vinyl or vinylidene compounds, such as kethacrylonitrile and ethylene glutaronitrile, vinyl esters such as vinyl acetate and vinyl ether. When acrylonitrile is copolymerized with diethyl methacrylate (alone), meltable and stretchable copolymers with excellent mechanical properties can be obtained,

The primarily molded articles made from the above copolymers are preferably produced by melt molding in the manner described below. It is there

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It is desirable that the copolymer have particular meltability for the proper performance of the Sehmelzfon process. Sin I-iaß for the flow properties of the molten copolymer is the amount of molten copolymer which flows out or is extruded through a fine opening at a certain temperature under a defined pressure. A method for measuring this so-called melt index is specified in ASTM D 1238. In the method according to the invention, the melt index of the molten copolymer is determined essentially according to the ASTM standard mentioned, although some measurement conditions have been changed, namely the outflow of the molten copolymer is determined at a temperature of 20O ⁰ C and a load of 21.6 kg .

When the article primarily molded from the copolymer is made by a melt molding process it is desirable that the melt index of the copolymer determined by the above method should be at least 1.5 g / 10 min and is preferably at least 2.5 g / 10 min. When the melt index of the copolymer is smaller than the above lower limit, melt molding of the copolymer without undesired thermal decomposition (the cause for excessive discoloration of the copolymer and the formation of infusible G-el) would be practically impossible.

There is no corresponding limitation in the process for producing the copolymer which can be used according to the invention. This copolymer can be prepared by any conventional aqueous system polymerization, such as suspension polymerization, Emulsion polymerization or dispersion polymerization can be made well.

109887/1732

When the primary molded article is produced by melt molding, it is desirable that polymerization conditions suitable for obtaining a copolymer having a molecular weight consistent with desired melt properties be selected, or suitable chain transfer agents such as mercaptans, _{or the like}

To produce the primarily shaped objects, such as, for example, poles, films, webs or pipes or hoses, a method can then be used in which the above-defined copolymer Z ₀ B ₀ through an annular or gap-shaped nozzle of a melt extruder at practical Absence of solvent for the copolymer is melt-extruded ₀ In this process, care must be taken that the primarily shaped object should not have such a thermal history that the copolymer in the shape of the primarily shaped object has become infusible before the secondary processing such άμΓΟίι stretching has taken place, "as explained below This means that the primary-molded article is said to be preferably to temperatures above 240 ⁰ C and preferably to temperatures above 235 ⁰ C -depending exposed.

As is well known, there is an acrylonitrile-containing Polymers and especially with the copolymers according to the invention, the difficulty that the polymer or copolymers become discolored and infusible when heated to too high! temperatures »

Investigations by the applicant have shown that a

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- ίο -

Oopolymer with 80 Grew.-Yes acrylonitrile units and 20 G-ev /.- ij methyl acrylate units, which has an Öchnielindex of 52 g / 10 rain at 200 ⁰ O and a load of 21.6 legs, when heated to 23O ⁰ O for about 30 minutes or to 240 ⁰ O for 15 minutes can be made infusible by the formation of cross-links ₉ The higher the temperature to which the copolymer is heated, the shorter the time for its cross-linking.

There is no limit to the thickness of the primarily shaped objects that can be used according to the invention. In view of the ease with which the primary molded article can be obtained and its use for manufacture However, the primarily molded article has a stretched shaped body preferably a thickness of 4 mm or less and in particular foils or webs with a thickness of 1 mm or less is useful.

The primarily shaped object produced in this way is brought to a temperature of 65 to 160 G and preferably from 70 to 150 ⁰ O and is mono-axially or multiaxially stretched to a predetermined stretching ratio of at least 1.5 in one or more stages »

When the primarily shaped article to be stretched has a temperature which is below the selected stretching temperature is, the stretching process after appropriate heating of the object using a for this Purpose of a suitable heating medium or heater. When the primary molded one obtained by melt molding Object is stretched immediately thereafter, this stretching can be done at a time when the temperature

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of the melt-molded object has sunk so far that the preselected stretching temperature is reached «

With an expansion ratio below 1.5 (based on the original dimensions of the primarily shaped object) the effects of the stretching process are so inadequate that the purpose intended according to the invention is not achieved is achieved. When the draw ratio is 1.5 or more, the desired properties of the drawn body can be obtained by appropriate definition of the stretching conditions including the stretching ratio and temperature, number of Corner steps and stretching direction taking into account the Yerarbeitbanceit be achieved in the stretching process "

According to the invention, the stretching process takes place at a temperature not below 65 ° G> because the primarily shaped object tears or breaks when stretched at a lower temperature or is partially cold-drawn, which results in a non-uniformity and poor quality of the stretched molded body brings.

The stretching process according to the invention takes place at temperatures up to 160 ° C., since a stretching process at even higher temperatures leads to a deterioration in the properties of the produced body, even if the stretching ratio is very high. Within the range 65-160 ⁰ O of the orientation effect at a given stretch ratio is higher in general, the lower the stretching temperature. Accordingly, in the practical implementation of the method according to the invention, the stretching eraper ature is taking into account the feasibility of the rear operation and the required for the correct shape body. appropriately determined or adjusted

109887/1732

Many stretching methods can be used to practice the invention applied - "'earth, Jinige examples are given below. For stretching a primarily in the form of a ϊΌϋe or web shaped object into a shaped body In a similar form, both batch operation and continuous operation are possible. in the In the former case, the side parts of the molded object are clamped in clamping jaws or clamping devices fastened and the clamped material by evenly increasing the distance ZAvischen the clamping points stretched. Stretching in more than one direction can take place in one or more stages »In the latter In this case, a so-called tentar process can be used. This process comprises 2 steps, wherein in one stage using a set of suitably arranged forging rolls in the longitudinal direction and in the other is stretched transversely to it with a set of clamping jaws, which are arranged so that the distance ζγ / ischen them increases. When the primarily molded article is in the form of a continuous tube or hose, is a so-called "pipe or hose process"?; endable. In this process, with the help of the internal pressure, a Stretched flow medium that is blown into the pipe. To generate or maintain a suitable internal pressure the stretching zone is usually made up of 2 pairs of pinch rollers disconnected. When such a pipe or hose process is used, the stretched shaped body is obtained in the form of a tube or hose, from which foils or webs can be produced by appropriate slitting.

It is also possible to manufacture containers, such as bottles, by simultaneously shaping and stretching the primarily shaped

109887/1732

An object, for example, using a so-called "blowing process" specified temperature range suitable In this "process is the draw ratio, viewed over the entire object, not uniform. I ¹ Ur latter method, the primary molded article are produced by a so-called ₀ casting polymerization"

The stretched molding can warmebehande.lt under various conditions as necessary for achieving certain properties are i "For example, the stretched i'omikörper by a liiärmebehandlung at temperatures of 120 ⁰ g or more given a high thermal dimensional stability are" Bine strong shrinkage for Useful for packaging purposes, can be imparted by heat treatment at a temperature below 12O ⁰ O «

Those in the form of Jolien, tracks, ribbons or certain Containers with complex shapes produced stretched Shaped bodies are because of their low permeability for gases, high transparency and high gloss as well excellent mechanical properties very useful.

If necessary, the stretched shaped body according to the invention can be used also a surface treatment, for example with printable agents, anti-static agents or lubricants be subjected to »The subject so treated

01887/173

can be used as packaging or wrapping material for different Goods find use. Sr can also be used together with other materials for wrapping Xomposit-Llaterial form / u

The molded article may eventually be t-shaped Contain additives, such as stabilizers for V'arms and light, Antistatic agents, lubricants, inorganic or organic dyes, such as paints or pigments and fillers and it can be colored, for example, by printing or coloring before or after sticking.

In the following, the invention is based on specific Examples are explained in more detail in these examples contained length specifications in "ropes" are on based on weight »

example 1

In a stainless steel polymerization reactor was a lionomer mixture of 60 ropes acrylonitrile and 40 parts of methyl acrylate with 0.55 ropes of n-octyl mercaptan introduced together with 200 parts of deionized Yfasser and 2 parts of "Pelex OTP" (emulsifier from Kao Atras Qo ", Japan).

Compartment exchange of those contained in the polymerization reactor air through nitrogen, 0.1 part of potassium persulfate was added to the reactor and the reaction mixture to Polymerization heated to a temperature of 65 ° 0, After completion of the polymerization, the resulting Polymers with the help of a small length of aluminum chloride . coagulated according to the conventional coagulation method,

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separated from the aqueous reaction system with water washed and dried

The dried polymer was tableted with a conventional extruder at a cylinder temperature of 200 ⁰ O and a Harzteniperatur of 190 G ⁰

The polymer tablets had a melt index of 58.1 g / 10 min at 200 ^° C. and a load of 21.6 kg. They were in an iOlienblasvorrichtung with a cylinder of 30 mm diameter with an annular nozzle located at the head of the cylinder with an outer diameter of 65 mm and a gap width of 0.5 mm at a cylinder temperature of 200 ° 0, a ütisentemperatur of 190 ⁰ G and a Resin temperature of 195 ° G melted and formed into a film at a blow ratio of 2 at a winding speed of 4 di / min (primarily molded object). The resulting unfair film had a thickness of 70 μm.

The foil was divided into rectangular test specimens with a length of 10 cm and a width of 5 cm cut. These test samples were placed inside a heating oven A llonoaxial stretching apparatus housed at a predetermined temperature clamped. The stretching apparatus could be operated from outside the furnace on the corresponding Distance between the two clamping parts for fixing of the test sample and taken out of the heating furnace. The test samples were uniform for 30 minutes heated for a long time to the various temperatures given in Table 1 and then at a stretching speed stretched from about $ 200 / min to the different stretching ratios also given in the table.

109887/1732

The resulting stretched films had the properties shown in Table ^1. 1

For lending purposes are in the table below 1 also specifies the properties of an unstretched film (control),

Table 1

Stern conditions Elongation
Relationship
nis 2.0 Strength and stretch
at the yield point strain
(tf) 7.3 3.5 ditto for breakage
or tearing strain
(^) Tempe
rature
(O ₀ ) control 2.7 Firm
speed
(kg / mm2) 4.5 6.9 4.0 Firm
speed
(kg / mni ^) 68 75 2.7 6.5 4.0 4.3 16 75 2.1 8.6 no flow quantities
ze observed 7.7 10 80 3.0 dito 11.9 11 90 14.5 25th 90 5.5 15th 8.0

Example 2

In the same way as in Example 1, a Go-

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polymer produced and tabletted "" The oopolymer tablets had a melt index of 21 g / 10 min at a temperature of 200 ⁰ O and a load of 21.6 kg Thickness of 80 μ formed-In the same way as in Example 1 from this film, test specimens were simultaneously biaxially stretched using a biaxial stretching apparatus housed in an oven at the various stretching temperatures and ratios given in Table 2 Pairs of clamping jaws or clamping points arranged in the right wimcel to each other for plaguing the hacking samples, which could optionally be set to the desired distance from outside the oven. The resulting biaxially stretched films had the properties given in Table 2 »

Table 2

Stretching conditions I. 90 Horizontal bar
behaves
nis in
Along
direction Horizontal bar
fade away
nis in
Transverse
judge ui 1.7 strength
and stretching in
Longitudinal direction Deh
tion strength
and stretching in
Transverse direction Deh
tion
W. Temp »
( ⁰ O) 90 control 2.2 ; "Firm
speed
_lg (kg / mm2) 100 Firm
speed
(kg / mm2) 20th • 90 1.7 2.3 - 7.0 69 7.0 57 2.1 .13.2 34 9.6 24 2.5 11.1 23 10.3 20th 13.4 10.1

109887 / -732

Example 3

Using the same process as in Example 1, an unstretched film with a thickness of 70 μ was produced from a tabletted copolymer of 80 % acrylonitrile and 20% ethyl acrylate, which had a melt index of 5.2 g / 10 min (at 200 ⁰ G under a load of 21.6 leg) had »

The film was prepared to a stretch ratio of 2.0 using the same apparatus as in Example 1 longitudinally stretched raonoaxially at different temperatures given in the table. The unstretched one and stretched polie had the properties shown in Table 2.

Table 3

uneven
te PoIi e stretched poIie 80 100 120 150 Tensile strength
speed (kg / nm2) 6.8 Stretching temperature ( ⁰ O) 11.3 11.0 10.0 8.0 Elongation at break
(*) 10 22nd 30th 30th 22nd

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Example 4

The same gopolymer tablets as in Example 2 were formed into a tube having a thickness of 100 µm and an outer diameter of 65 µm using the same film forming apparatus as in Example 1 without blowing air into the tube. This tube or "the Sehlauch was passed through a pair of rollers or pairs of rollers, the or cdi a distance of about 150 did from each other (s)," The rollers were driven independently and the downstream roll had a special channel or groove for Blowing air into the pipe passing through. Before it passed the upstream roller, the tube was ^{brought to a temperature of about 80 0} O on the outer circumference by an electric heater, formed into a cylinder under the pressure of the air blown through the channel after passing the upstream roller, and then by a second electric heater heater heated to about 90 ⁰ O "the tube was stretched at a stretch ratio of 2 in the tube longitudinal direction by controlling the rotational speeds of the rollers, and further at a draw ratio of about 2, a in Rohrquerriehtung by the JMillung of the heated by the second heater tube by raising the Air pressure in the pipe immediately after passing through the second heater. The resulting stretched hose had a thickness of 20 to 25 W. The unstretched and stretched hose had the strength and elongation values given in Table 4 in the longitudinal and transverse directions of the hose .

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Table 4

Longitudinal direction of the
Hose fracture
strain
(fr) Hose cross -
direction Fracture-
strain
A » unstretched
hose Tear
strength
(kg / niia ² ) 23 Tear
strength
(kg / mm2) 2Ό more stretched
hose 6.6 53 6.2 61 14.5 11.4

Example 5

From 70 parts of acrylonitrile, 20 parts of ethyl acrylate and 10 parts of diethyl methacrylate, gopolymer tablets were prepared by the same process as in Example 2. The copolymer had a melt index of 15 g / 10 min at 200 ^° C. and a load of 21.6 kg.

The copolymer tablets were formed into a web with a thickness of 100 μm with the aid of an extruder with a cylinder of 25 mm diameter and a Ϊ-nozzle with a gap opening of 0.2 mm width and 5 cm length. The resulting unstretched sheet was stretched in the web longitudinal direction with a stretch ratio of 2.5 at 100 G ^0. The stretched web had a thickness of 60 to 70 u. The unstretched web had a tensile strength of 6.5 kg / mm and an elongation at break of 35 /, while the corresponding values of the stretched web were 13.0 kg / mm ² and 20 ? » lay.

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Example 6

A pelletized copolymer of 80 parts of acrylonitrile and 20 parts of ethyl acrylate with a Schinelz index of 19.5 g / 10 min at 200 ⁰ O and a load of 21.6 kg was formed into a polie with a thickness of about 200 μm by a blow molding process the copolymer melted and extruded at a temperature of 200 ⁰ C. The resulting unstretched pile was cut into test specimens 8 cm long and 4 cm wide. The test samples were stretched using a manual stretching device at 100 ⁰ C and a draw ratio of 4 at a stretching speed of 300 ji / RNIN monoaxially. The stretched samples were fixed on a metal frame with no dimensional change { and heat-treated in a constant temperature bath whose treatment temperatures shown in Table 5 were maintained for 30 minutes.

Table 5 shows the shrinkage values of the samples heat-treated at the specified treatment temperatures at a temperature of 100 ° 0., the shrink temperature door, where the heat treated samples show $ 10 shrinkage and the ultimate tensile strength and elongation at break of the heat treated samples.

The stretched samples were ärmeschrpfνerhaiten from the relation between heating temperature and shrinkage ™ of the sample determined at a heating rate of 2 ° G / min. The tensile strengths and elongations at break were determined in a tensile test according to ASTM D 882-54T.

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213B222

! Table 5

Heat treated
lung temperature
rature
(° 0) Shrink
fungus
100 ° G
( ^c / 5) temperature
at 10 ^ 3
shrinkage
(° 0) Tear
strength
(kg / mm ² ) fracture
strain
(*) no 41 78 17.80 7th 100 23 89 17.00 10 120 7th 106 16.40 16 150 6th 120 13.00 16 180 4th 130 11.20 24

Example 7

Of 80 parts of acrylonitrile and 20 parts of a copolymer was prepared Hethylaerylat · This copolymer had a (SLAs) -iibergangstemperatur of 94- ⁰ O and a melt index of 19 "3 g / 10 min" - The copolymer was prepared using a Folienblasvorrichtung to a EoIIe shaped and having a thickness of 200, said melted the copolymer and was extruded at a temperature of 200 ⁰ C, the resulting unstretched film was measured with a Reekverhältnis of 3 at a temperature of 100 ⁰ C or 150 ⁰ O at a stretching speed of 500 $ / min stretched monoaxially. The stretched films were 2 minutes at temperatures of 100 ⁰ C, 120 ° or 150 0 ⁰ C under tension heat treated "Table 6 shows the heat shrinkage of the heat-treated films obtained after the same heating

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method in air as in Example 6 was measured. In the The table also shows the tensile strength and elongation at break in the stretching direction (determined in accordance with ASTLi D 882-64T).

Table 6

Horizontal bar
tempe-
rature
'( ⁰ O) Heat dissipation
action
tempera-
door
( ⁰ G) tempera
ture at
Shrink
function sbe-
start
( ⁰ G) tempera
ture at
completely «,
Shrink
fung
( ⁰ O) Tear
firm
speed
(kg / mnr) fracture
deh
tion
. (50 100 100 72 130 14.00 18th 100 120 72 190 15.40 24 100 150 90 180 13.00 16 120 120 95 170 12.40 20th 120 150 125 180 11.50 H 150 150 116 200 10.20 20th

The "temperature at full *" specified in the table above constant shrinkage "is the temperature at which - based on the elongation imparted to the unstretched film during stretching ~ a 90 to 100% shrinkage of the film was established =

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Example 8

The same unstretched l'olie as in Example 7 was cut into test specimens of 8 cm in length and 4 cm in width, and the specimens with a corner ratio of 3 - and a stretching speed of 5Ü0 ye / stretched in their longitudinal direction under stern conditions as given in Table 7. The stretched samples were treated under the conditions given in Table 7

The heat shrinkage properties of the stretched and heat-treated samples and the stretched but not?; poor treated samples are given in Table 7 «

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-? 2fji jcj. · -. -λ «* ,: a

(Table 7

\ Treatment
Ν. or ο
\ Unters «
Per- \.
ben \. Horizontal bar
tempe-
rature
( ⁰ G) Heat 3c
handy fu
ment 1 hrump-
ng at
00 ° 0
(S) Tempe
rature
at
1Of ₀
Shrink
fung
(° o) Disintegrating
tear
fe-
stig-,
- Iceit
(kg / mm ' fracture
deh
tion
W.
² ) stretched
and
warmth
acted
foil 100 120 ⁰ G
Dimen
sions
^ firmly 6th 112 15.50 17th ' Foil,
only ge
stretches 100 150 ° 0
Dimen
sions
fixed 4th 130 12.00 22nd 100 18O ⁰ O
Dimen
sions
fixed 2 140 10.20 26th 100 15O ⁰ O
Dimensio
a tight
then
12O ⁰ O Tue
dimensions
not fixed 0 145 10.50 28 150 150 ⁰ C
Dimen
sions
' fixed 4th 122 11.50 20th 150 15O ⁰ O
Dimensio
a tight
then
15O ⁰ O Tue
dimensions
not fixed 0 140 9.80 23 100 no 40 84 17.20 16 150 no j 40 96 - 12.10 22nd

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• Example 9

The same unstretched film as in Example 8 were in test samples of 8 cm long and 8 cm wide cut, and samples with a stretch ratio of 2 in the longitudinal direction and transverse direction at a temperature of 100 ⁰ G, and a stretching speed of 500 $ / stretched min equilateral biaxially . The stretched samples were heat-treated at the temperatures given in Table 8 with fixed dimensions for 15 minutes. Table 8 shows the temperatures for initial shrinkage and 30% shrinkage as well as the tensile strength and elongation at break of the unstretched and stretched samples,

Table 8 '"

Heat dissipation
action
temperature
(First floor) Measuring
rich
tion tempera
ture at
Shrink
qualification
start
( ⁰ G) tempera
ture at
30 ^c / i
Shrink
fung "
( ⁰ G) Tear
firm
speed
(kg / mm ² ) fracture
deh
tion
(5b) control along
across 72
73 95
96 16.00
15.00 37
35 100 along
across ■ 72
74 120
122 14.40
13.00 38.
30th 120 along
across 76 ·
78 144
146 13.20
12.50 32
30th

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The above properties were determined using the same methods as in Example 7,

As can be seen from the table, the sample heat-treated after stretching is capable of heat shrinkage within a wide temperature range from low to high temperature and can therefore be broken as a severely shrinking film "

Comparative example

Test samples which had been produced from the same unstretched film as used in Example 8 were stretched at a temperature of 6C ⁰ C or 170 ⁰ G under the same conditions as in Example 8. At a temperature of 60 °, stretching was difficult because of frequent tearing and necking of the film, and uniform stretched films could not be achieved. 2ei 17O ⁰ C had the stretched I ¹ Hn a relatively low tensile strength of 7.50 kg / mm and a relatively high elongation at break of 35>. That is to say, if the primarily shaped object is stretched at temperatures outside the range defined according to the invention, unfavorable results are achieved.

109887/1732

Claims (1)

1 ο / Process for the production of a stretched molding f acrylonitrile-based, characterized in that a primarily shaped object from a G o polymer of 55 to 85 wt. <> - / <> acrylonitrile units and 15 to 45 wt have up to 4 carbon atoms, in which the alkyl acrylate content is up to half by at least one other copolymerizable monomer. can be replaced, with an elongation ratio of at least 1.5 in at least one direction and at a temperature of 65 to 160 ⁰ G in the practical absence of solvents for the copolymer " 2 "The method according to claim 1, characterized in that the primarily shaped object is produced by melting the copolymer at a temperature not above 240 ⁰ G and then shaping the melt through a nozzle ο 3o method according to claim 1, characterized in that the stretched molding continues to be subjected to a heat treatment at a temperature not below 120 G » 4. The method according to claim 1, characterized in that the stretched molding is further subjected to a heat treatment at a temperature below 120 ⁰ G. 5o method according to claim 1, characterized in that 109887/1732 of the primary-molded article has a softening temperature of not lower than 60 ⁰ O. 6ο method according to claim 1, characterized in that the other with acrylonitrile and alkyl acrylate copolymerizable lionomer by a compound from the group of styrene, LIethyl methacrylate, vinyl chloride, vinylidene chloride, methacrylonitrile, Methylene glutaronitrile, vinyl acetate and vinyl ether is formed » 7o method according to claim 1, characterized in that that the copolymer has a melt index (determined according to " ASTM D 1238 but at 200 ⁰ G and 21.6 kg load) of at least 1.5 g / 10 min has " 8o method according to claim 1, characterized in that that as stretched molded bodies i'olien, webs, tapes or Pipes or hoses as well as containers such as bottles or Bowls are made « 9ο method according to claim 1, characterized in that that the stretched moldings are shaped by a tentering process » 1Oo method according to claim 1, characterized in that that in particular the stretched Ioria body produced from acrylonitrile and alkyl acrylate by a pipe or hose process be generated"