DE2436137A1 - MIXED POLYMER - Google Patents

Description

Mixed polymer
Priority: July 26, 1973 - Great Britain

The invention relates to uniform copolymers of acrylonitrile and methacrylonitrile which are suitable for the Manufacture of naturally degradable items are suitable.

It is known that polymers containing high acrylonitrile or methacrylonitrile, including those obtained by mixing with a compatible rubbery Graft copolymer containing a superstrate of the acrylonitrile or methacrylonitrile polymer made tough suitable materials for the manufacture of wrappings and containers (such as bottles, bags, Sacks, boxes, cartons, sachets and cups) are for food and medicine as they are in processed form for many gases are only very weakly permeable and, since they are highly resistant to a wide range of chemicals, excellent mechanical properties and high Have softening point. Casings made from such polymers are particularly useful for food

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and medicines because they protect the contents from the ingress of the surrounding air. Similar bottles made from the Polymers made are suitable for storing carbonated beverages because of the loss of carbonation takes place very slowly through the walls of the bottles.

Polyacrylonitrile itself is not suitable for such applications because it has poor thermoplasticity and thermal stability due to its crystallinity. In addition, articles molded from polyacrylonitrile are prone to rupture, being stressed

ρ ρ

break of often only 2 kg / mm and rarely more than 4 kg / mm,

when its bending strength is measured at 2O ⁰ C. To overcome these difficulties, acrylonitrile is copolymerized with small amounts of one or more other monomers so that its crystallinity is reduced, thereby increasing the melt flow and thermal stability in the melt and improving the impact resistance of the articles made therefrom. Polymethacrylonitrile, on the other hand, is amorphous and can be used for such purposes. Even so, it is often preferred to use a small amount of comonomer in order to improve the processability and thermal stability of the methacrylonitrile polymer. However, in order to maintain the good barrier properties (and the other good properties such as chemical resistance) of polymerized acrylonitrile and methacrylonitrile, it is generally advisable that the interpolymer contain at least 50 mol of acrylonitrile or methacrylonitrile units. The exact molar composition of an acrylonitrile or methacrylonitrile mixed polymer is selected according to the desired processability of the resin and the mechanical and release properties which the objects made from it are to have *.

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However, the use of plastic wrappings and plastic containers for food and medicine has waste problems result, which could become serious if the consumption of such items continues to increase.

Ξε is known that objects are made from a wide variety of polymers (polygamy by radical polymerization ν; orders are) are made naturally degradable in that the main monomer component of the polymer with certain ethylenically unsaturated monomers containing a ketone group, is copolymerized. It is believed that the ketone group acts as a prodegradant and the polymer chains for one Makes absorption of UV radiation accessible, whereby the chains are cut into smaller units, so that biological Microorganisms can penetrate and attack more easily.

Thus, according to the invention, there is a uniform copolymer that is suitable for the manufacture of naturally degradable articles suitable, suggested that 50 to 98 mol # acrylonitrile units or 50 to 99.9 mol- # methacrylonitrile units and 0.1 to 25 mol- ^ uniformly distributed units of one Ethylenically unsaturated ketones of the general formula

R ₁ O

CH ₂ = C - C -

wherein R represents an alkyl, alkaryl, alkenyl or aryl group having 1 to 9 carbon atoms and R represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. stands, and from 0 to 49.5 mol- # units of at least one other Contains ethylenically unsaturated monomer, the amounts being selected so that a total of 100 mol-56 come out.

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It has been shown that when the units of the Ethylenic unsaturated ketones are uniformly distributed in the acrylonitrile or methacrylonitrile copolymer, each contribution, which they contribute to improved properties of the mixed polymer, such as improved deformability in the Heat (especially compressibility) and improved thermal stability, is considerably reinforced. It will assumed that with a uniform distribution of the ketone units their "effectiveness as a prodegradant in the copolymer is also improved.

As mentioned earlier, acrylonitrile and methacrylonitrile polymers, which are used for the production of casings and containers contain at least one comonomer, to reduce the crystallinity (in the case of polymerizing acrylonitrile chains) or to reduce the processability and to improve the thermal stability (in the case of polymerized aerylonitrile or methacrylonitrile chains). Thus, the interpolymers of the present invention can be simple and uniform binary interpolymers of acrylonitrile or methacrylonitrile with up to 25 mol # ethylenic be unsaturated ketone, the latter acting both as a prodegradant and as a comonomer and the desired Brings about improvements in properties. However, it is more preferred that these improvements are mainly by incorporating one or more further comonomers in addition to the ethylenically unsaturated ketone in the polymer chain.

Other suitable comonomers for this purpose are olefins, including hydrocarbons or substituted hydrocarbons, which contain at least one functional ethylenic bond are to be understood. Particularly suitable olefins are monomers in which the functional ethylenic double

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bond is conjugated with an aromatic ring, that are So aromatic olefins such as styrene, oc-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,5-dimethylstyrene, p-methoxystyrene, p-dimethylaminostyrene, p-acetamidostyrene, m-vinylphenol, p-trimethylsilylstyrene, ar-dibromostyrene, 1-vinylnaphthalene, acenaphthylene, 3-vinylphenanthrene, 2-vinylthlophen, Indene, coumarone, N-vinylcarbazole or vinylpyridines, (such as 2-methyl-5-vinylpyridine). Of these, styrene and oC-methylstyrene, either alone or as a mixture, are preferred.

Other suitable olefins are alkenes, such as ethylene, propylene, butene-1, isobutene, pentene-1, 4-methylpentene-1, octene, octadecene, Cyclohexene and methylcyclohexene, as well as dienes such as butadiene.

Further suitable comonomers are vinyl acetate or others Vinyl ester, vinyl chloride, vinylidene chloride, vinyl fluoride, Vinylidene fluoride, hexafluoropropene, tetrafluoroethylene and Chlorotrifluoroethylene and electron-deficient vinyl monomers such as acrolein, acrylic acid and methacrylic acid as well as the esters thereof.

Small amounts of ethylenically unsaturated monomers that selected from maleimide and its N-substituted derivatives and norbornene and its derivatives can also are incorporated into the acrylonitrile or methacrylonitrile copolymer to increase the softening point to achieve.

To the properties of the acrylonitrile or. Methacrylonitrile copolymer To optimize, all comonomers present in addition to the additional ethylenically unsaturated ketone must also be present uniform in the acrylonitrile or methacrylonitrile

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polymer chain be distributed, so that the copolymers according to the invention may be referred to as "uniform interpolymers".

By the term "uniform interpolymer" in this specification is meant a copolymer in which the initially The polymer molecules formed by the reaction have substantially the same average composition as that later educated. Because of the great ease with which many monomers, especially conjugated aromatic olefins, copolymerize in the presence of a high proportion of acrylonitrile or methacrylonitrile, there is a tendency that the mixed polymer formed at the beginning of the reaction at the expense of the mixed polymer portion formed towards the end of the reaction is enriched in the comonomer. The latter, i.e. the mixed polymer formed at the end of the reaction, therefore has more of the unfavorable properties of polyacrylonitrile or polymethacrylonitrile, if precautions are not taken, the monomers (or at least the faster reacting monomer) to be introduced into the reaction medium throughout the course of the polymerization * A convenient method for doing this is described in GB-PS 1 197 721, the content of which as in the This application is intended to apply included. In this method, the heat of polymerization during the reaction measured by calorimetry., and the monomer is added according to the heat generation.

In principle, the total amount of heat developed per gram of polymer formed can be derived from the heats of the interpolymerization of the monomers or approximately from their known heats of homopolymerization. Thus the maximum amount the heat until the end of the polymerization can be predicted for each case. Likewise, the total amount of monomer, which for a 100 # yield of interpolymer of the desired composition must be added, calculate in advance

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BATH ORIGINAL

net. This also enables the amount of monomer to be added to be calculated which corresponds linearly to a measured amount of heat. Any accidental heat loss from the system or all accidental heat absorption by the system is determined by calculation and / or by experiment and during the determination of the measured heat in the invoice.

The composition of the mixed polymer formed depends very strongly on the concentration of the monomers in the polymer mixture. This gives the amount of each monomer required in the initial batch. Published data allow to calculate this sufficiently, although in some cases empirical refinements may be required until the interpolymers have the optimal physical properties, for example in a given good clarity of express pressed parts made from it.

For example, to make 100 g of a uniform Mixed polymer of acrylonitrile and styrene the amount of Styrene to be mixed with the entire required amount of acrylonitrile in the initial batch, for copolymers calculated with various styrene contents. The results are given in the following table. (The rest of the styrene was added continuously during the polymerization).

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Styrene in the
Initially charge Acrylonitrile Styrene in
Mixed polymer 0.45 cn? 115.5 cirr 5 MoI-Ji 0.86 cn? 102.7 cn? 10 MoI-Ji 1.40 cn? 95 * 0 ciP 15 moles ^ 1.65 cn? 88.5 on? 17.5 mole # 1.94 cn? 84.0 cn? 20 MoI-Ji 2.67 cm ⁵ 75.6 cn? 25 MoI-Ji

The ethylenically unsaturated ketone that is uniformly incorporated into the acrylonitrile or methacrylonitrile copolymer is to be incorporated in a similar V / eise as it was described above for styrene, if its reactivity is high compared to that of acrylonitrile or methacrylonitrile, i.e. that part of the ketone is in the initial batch and the remainder is added continuously during the polymerization, the amount of ketone in the initial batch required to achieve the desired interpolymer composition by calculation and empirical Observation is determined. ..If, as is preferred, the acrylonitrile or methacrylonitrile copolymer at least contains another randomly distributed comonomer of high reactivity (such as styrene), then the ketone and the additional monomers added during the polymerization are combined and added as a single charge. But when the ketone has a reactivity which is essentially that of acrylonitrile or methacrylonitrile with corresponds to which it is to be copolymerized, then everything can expediently be added to the initial batch.

Examples of ethylenically unsaturated ketones that are used in the manufacture of the copolymers according to the invention can be used are methyl vinyl ketone, isopropyl vinyl ketone, n-butyl

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vinyl ketone, methyl isopropenyl ketone, ethyl isopropenyl ketone, Methyl sec-butenyl ketone and phenyl vinyl ketone.

The preferred acrylo.nitrile copolymers according to the invention contain between 66 and 95 mol ^ acrylonitrile. Those, the 80 to 95 mol- ^ (very particularly 86 to 95 mol- #, especially 86 to 90 MoI- ^) are particularly preferred, as im generally those copolymers containing more than 95 mol ^ acrylonitrile are difficult to process without decomposition under certain conditions, while a gradual decrease the acrylonitrile content below 80 MoI- ^ a reduced Strength, rigidity and resistance to chemical ' Result in an attack. The preferred methacrylonitrile copolymers according to the invention contain between 70 and 98 mol Ji, in particular between 85 and 95 mol - $>, methacrylonitrile units.

Particularly preferred copolymers according to the invention are terpolymers, the (1) acrylonitrile, (2) an ethylenically unsaturated ketone and (5) an aromatic olefin (especially styrene or ot-methylstyrene) or acrylic or methacrylic acid or one Contain esters thereof, the monomer (3) preferably in an amount of 5 to 15 MoI-J?!, In particular 8 to 12 Μ0Ι- & is present.

The mol - ^ - ratio of the copolymerized ketone units in the copolymers according to the invention is generally quite small and is usually between 0.1 and 5 mol- & preferably between 0.5 and 1 mol- ^ (in particular between 1 and 2.5 mol- #). However, E ^s is within the range of the invention, substantially larger quantities ketone units in the copolymer (for example, 5 to 25 mol #, preferably 5 to 15 mol #) incorporate and use the obtained copolymer example, as base mixture. It can be said that by diluting such a basic mixture with further

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2 A 3 6 13

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Acrylonitrile or methacrylonitrile isohpolymer (which does not contain any Contains ketone units according to the invention), so da.3 the total concentration of the ketone is greatly reduced, for example to 5 mol-2> or less, a polymer should be obtained which also has useful natural degradability.

The copolymers according to the invention can be modified as a result that you can use lubricants, plasticizers, stabilizers, optical Brighteners and fillers, such as colloidal rubber particles or glass fibers, before processing into molded articles incorporated. Their molecular weight can be controlled by using chain transfer agents such as alkanethiols, incorporated during the polymerization.

An important use for the copolymers according to the invention is as a resin superstrate of a graft copolymer with a Rubber substrate. . Another possible use is as a resin component (which does not contain rubber) of a mixture with a compatible graft copolymer that is a rubber substrate having. Graft copolymers are suitable for such mixtures, a polybutadiene substrate and a superstrate of acrylonitrile / isobutene mixed polymer (as in GBPS X · 14 ^ 5 4o8) or made of a uniform acrylonitrile / styrene copolymer with a high percentage of acrylonitrile (as described in GB-PS 1 185 J506). However, the superstrates of such graft copolymers are preferably uniform copolymers of the present invention. A graft copolymer or mixture as described is generally tougher than the untreated one copolymer according to the invention and therefore has, for example, a higher impact resistance. The elastomer im However, graft copolymer or in admixture somewhat reduces the impermeability and rigidity of the composition. It is important, when blending the instant copolymers, to use a graft copolymer that is compatible therewith.

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borrowed when the desired level of toughness can be obtained target. Preferred graft copolymers for blending with the uniform copolymers of the present invention are those having a superstrate of approximately the same composition as the uniform interpolymers.

The invention is illustrated in more detail by the following example.

EXAMPLE

The production of a uniform ternary mixed polymer from acrylonitrile styrene and methyl vinyl ketone with molar ratios of 81.4: 10.9: 7 * 7 was obtained using the device carried out as described in Fig. 1 of GB-PS 1,197,721.

The initial batch consisted of 1,400 ml of distilled water, 589.8 ml of acrylonitrile, 36.0 ml of styrene, 41.8 ml of methyl vinyl ketone, 2.0 ml of n-octyl mercaptan, 1.7 g of sodium dodecyl benzenesulfonate and 1.9 ml of 10 ^ iger sulfuric acid. The air was removed and the mixture was heated until it had a temperature of 56.5 ⁰ C. The polymerization was then initiated by adding 2 ml of a solution containing 5 g of ammonium persulfate per 100 ml of water and 1 ml of a solution containing 1 g of sodium metabisulphite per 100 ml of water. The temperature rose rapidly to 69.5 ° C. It was necessary to moderate the reaction during the following 10 minutes by adding small amounts of sodium dimethyl dithiocarbonate. ■

After the temperature began to rise, a mixture of 80, 4 ml of styrene, 0.97 ml of methyl vinyl ketone and 2.0 ml n-octyl mercaptan is introduced in a linear fashion to the initial charge at the rate of polymerization so that, after the polymerization was over (corresponding to the polymerization of the entire Acrylonitrlls), the total amount

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of the styrene (80.4 ml) in the feed was added. The temperature was kept between 61 and 64 ° C. by adding a total of 2 ml of ammonium persulfate solution. After 5½ hours, after 65 % of the feed had been added (equivalent to a 65% conversion), the reaction gradually slowed down. The reaction was then stopped by adding a mixture of 0.2 g sodium hydroxide, 0.4 g tetrasodium pyrophosphate, 0.6 g sodium formaldehyde sulfoxylate and 50 ml water.

To isolate the mixed polymer, the latex was coagulated from the reaction vessel using 4 liters of an aqueous solution of magnesium sulfate heptahydrate (it contained 1 g per 100 ml of water) at 80 ° C. The obtained polymer was washed three times by stirring in distilled water at 70 ⁰ C, and then washed once with distilled water at 90 ° C and finally rinsed with methyl alcohol and dried in vacuum oven at 80 ⁰ C.

A portion of the polymer was at 200 ° C in a plate with the dimensions 10.2 cm χ 5.1 cm χ 0.52 era pressed (applied with a pressure of 20 tons during 5 minutes), whereupon the Sehlagfestigkeit at 20 ⁰ C was measured on an unnotched sample cut from the compact.

The impact strength (unnotched specimen) was measured with a specimen of 0.9 cm wide and 0.2 nwi thickness determined horizontally (with the narrow surface facing up) on two supports, which were j5.8 µm apart, rested. The sample became central On the wider surface it was pushed by a horizontally moving pendulum * which fell from> 0 cm, whereby the energy was greater was when it was required to break the specimen. From the the remaining energy of the pendulum was calculated as

which was required to break the specimen. This then divided it by the effective area at the break point. The resulting value (expressed in kJ / cm) represented the energy that was required to create a crack in the material to create.

This value was found to be 28 kJ / m.

Similar samples underwent UV exposure in a polymer exposure unit subjected for 7, 14 or 21 days before the impact strength was determined on unnotched specimens, This unit contained a combination of equal numbers of 20 watt fluorescent sun lamps and black 20 watt lamps, with the samples spaced 10 cm apart around the lamps (the circular arrangement served to achieve uniform irradiation).

2 The impact strengths of the unnotched samples were 9 * 2 kJ / m

(7 days), 2 kJ / m ² (14 days) and 1.8 kJ / m ² (21 days).

Samples of a similarly prepared uniform copolymer of acrylonitrile and styrene (containing 87.5 mole # acrylonitrile and 12.5 mole # styrene, but none Methyl vinyl ketone) were used in the same exposure unit treated during the same time as the above samples. It became the following fourth for impact resistance

2 2

obtained on unnotched samples: 21 kJ / m (7 days), 25 kJ / m

(14 days) and 20.5 kJ / m ² (21 days).

The above test results show that the invention Mixed polymers apparently through a chain break UV radiation are very accessible, which results from the drastic loss of impact resistance. The copolymers that did not conform to the present invention did not show such accessibility.

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This accessibility confirmed to Kettendurchtrennun ^ WUI Depending by a further Verbuch, in which a film ve η O, ^C 5 mm thickness of the above ternary mixed polymer from Aerylonlti-Ll, styrene and methyl vinyl ketone J22 hours UV light, in which The above polymer exposure unit was exposed, and zv.ar together with a similar film, which had been made from the above-mentioned mixed polymer of acrylonitrile and styrene (containing no KethyI-vinyl ketone). The reduced viscosity of the ternary mixed polymer (measured on a 0.5 sequence (w / v) solution in dimethylformamide at 25 ° C.) was reduced from an initial value of 1.47 to a final value (after exposure) of 0.6o. In contrast, the initial reduced viscosity of the mixed polymer which did not contain methyl vinyl ketone remained unchanged at 0.73.

D *. ~ Ü * ». M.H! CKE. do,.

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ORIGINAL

Claims (1)

Claims 1. Uniform copolymer which is suitable for the production of naturally degradable objects, characterized in that it contains 50 to 98 mol- $ acrylonitrile units or 50 to 99.9 mol- # methacrylonitrile units, 0.1 to 25 lAol% uniformly distributed units of an ethylenically unsaturated ketone of the general formula R ₁ 0 wherein R represents an alkyl, alkaryl, alkenyl or aryl group having 1 to 9 carbon atoms and R represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and 0 to 49.5 molar units of at least one contains further ethylenically unsaturated monomer, the total amounts adding up to 100 mol-fo. 2. Uniform copolymer according to claim 1, characterized gees indicates that / 0.5 to 3 mol $ units of said ketone contains. J. Uniform interpolymer according to claim 1 or 2, characterized characterized in that it contains 80 to 95 mole acrylonitrile units. 4. Uniform copolymer according to one of claims 1 to 3, characterized in that it is 70 to 98 mol $ methacrylo contains nitri! units. 509807/1056 f). Uniform mixed polymer according to one of Claims 1 to k, characterized in that it is a ternary mixed polymer of (1) acrylonitrile (2) an ethylenically unsaturated ketone and (3) an aromatic olefin or aoryl or methacrylic acid or an ester thereof . 6. Uniform copolymer according to claim 5> characterized in that that there are 5 to 15 MoI- ^ units of styrene as contains aromatic olefin. 7. Uniform copolymer according to any one of claims 1 to 6, characterized in that it is the superstrate of a Is graft copolymer with a rubber substrate. 8. Use of the uniform interpolymers according to a dor claims 1 to 7 for the learning of packaging materials. * KWm ANWÄLTE Κ FiNCICE, DIPl.-iNG.mOHk Mft-MO. S. STAWOI 5 O 9 B O 7 / i