DE1900134B2 - Relatively transparent polymer blend contng styrene - Google Patents

Abstract

Polymer blend consists of fine and coarser particles of 2 graft copolymers of styrene/acrylonitrile copolymer on rubber and matrix of styrene/acrylonitrile copolymer. Blend is relatively transparent and coarser particles impart toughness. Components are easy and cheap to prepare and process is simple and effective. For packaging foodstuffs etc.

Description

a) a graft copolymer obtained by aqueous emulsion polymerization of styrene and acrylonitrile was obtained on a diene latex, finely divided graft copolymers with small particles of less than 0.2 microns and

b) a graft copolymer obtained by mass / suspension polymerization of styrene and acrylonitrile was obtained on a diene rubber, graft copolymers with larger particles from about one to a few microns can be obtained.

This is a mixture of two graft copolymers with different particle sizes, the latter being due to the production methods of the graft copolymers. A targeted one The aim is not to use certain particle sizes. A targeted production relatively more transparent Polyblends are not possible with the known mixture.

The invention is based on the object of producing relatively transparent polyblends.

According to the invention, this object is achieved in that the mean particle size of the first graft copolymer B) is 0.7 to 2.5 microns, the second graft copolymer C) a ratio of graft price to the graft base from 50 to 200: 100, the graft bases together 0.5 to 20% by weight of the Make up the polymer mixture and the graft base of the second graft mixed polymer C) to the Graft base of the first graft mixed polymer

B) has been used in a weight ratio of 4.0 to 32: 1.

Further refinements of the invention are contained in the subclaims.

The advantage that can be achieved with the invention is to be seen in the fact that relatively transparent polyblends are created that have desirable impact properties at the same time, which makes them especially for packaging and makes other applications suitable.

When determining the particle size, a dispersion of the mixed graft polymer is produced and a photograph with the electron microscope

made of it. There should be around 200 to 1000 particles measured and counted to obtain a representative number average.

The theory is still perfectly clear. However, it is believed that the large amount of small, in high degree of grafted copolymer particles for the composition have an apparent refractive index results, which is close to the apparent refractive index of the large graft copolymer particles comes. In any case, the large particles do not make the composition opaque, even though they are in the Composition are present in amounts that will allow this in the absence of small, highly grafted Copolymer particles would make opaque. It is believed that the small amount of large Graft copolymer particles create a basic level of toughness that is achieved by the small graft copolymer particles is expanded in such a way that the gloss and tensile properties of the composition are kept at desired values. Apparently the small particles fill the rooms between the large particles and increase the toughness of the mixture and reach a certain level Homogeneity of the graft copolymer within the Matrex.

The copolymers of both the Matrex and the grafts according to the invention consist in the Mainly from an aromatic monovinyl hydrocarbon and an unsaturated nitrile, i. i.e., this Monomers make up at least 50.0% by weight and preferably at least 75.0% by weight of the copolymers the end. Most desirably, such monomers make up at least 85.0% by weight of the interpolymer and the usual commercial compositions are essentially composed entirely of such monomers when minor amounts, i.e. H. less than 5.0% by weight of other components such as Chain transfer agents, modifying agents, and the like.

Understandably, the copolymers used for the grafts should be used with the copolymers be compatible with the matrix in order to obtain good properties in this way, which the Requires presence of relatively similar monomers. In general, the additional copolymers are used the chemical composition of the copolymer of the matrix very close, so that a Matching the chemical properties is achieved, and consequently it is desirable that the conditions of the two graft copolymers are very similar to one another. It is also believed that thereby increased chemical bonding with a simultaneous improvement in chemical properties is obtained. It however, it is clear that for some applications there will be deviations in the composition of the copolymers the matrix and the pads, such as different monomers and / or ratios, may be desirable and that certain deviations occur naturally as a result of process variables can.

Examples of aromatic monovinyl hydrocarbons used in the copolymers are styrene, monoaromatic alpha-alkyl monovinyl compounds, for example

alpha-methylstyrene,

alpha-ethylstyrene,

alpha-methylvinyltoluene,

alpha-methyldialkylstyrenes and the like,

ring-substituted alkyl styrenes, for example

Vinyl toluene,

o-ethylstyrene,
p-ethylstyrene,

2,4-dimethylstyrene and the like,

ring-substituted halostyrenes, for example

ο chlorostyrene,

p-chlorostyrene,
ίο o-bromostyrene

2,4-dichlorostyrene and the like,

ring alkyl,

ring halogen substituted styrenes, for example

2-chloro-4-methylstyrene,
2,6-dichloro-4-methylstyrene and the like,

Vinyl naphthalene,

Vinyl antliracene and the like.

The alkyl substituents generally have 1 to 4 carbon atoms and can be isopropyl and isobutyl groups lock in. If desired, mixtures of such monovinyl aromatic monomers can be used be used.

2 ") Examples of unsaturated nitriles that can be used in the copolymers are acrylonitrile, methacrylonitrile, ethacrylonitrile and mixtures thereof.
Examples for; Monomers with the aromatic

jo monovinyl hydrocarbons and the unsaturated ones Nitriles that can be copolymerized are alpha- or beta-unsaturated monobasic acids and Derivatives thereof, for example acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,

j ") methacrylic acid and the corresponding esters thereof, Acrylamide, methacrylamide, maleates or fumarates, such as dimethyl maleate, diethyl maleate, dibutyl maleate, the corresponding fumarates and the like. The person skilled in the art knows that the amount of these comonomers used in

»Ο the mixed polymer can be introduced as Score will vary depending on various factors.

In addition, the monomer formulation can be a preformed polymer at the time of polymerization or contain a partially polymerized material,

4> for example a partially polymerized aromatic Monovinyl hydrocarbon or a copolymer thereof.

The copolymers of the pads contain at least 30% by weight of the aromatic monovinyl

· ■> (> monomeric and preferably at least 60% by weight of that. They also contain at least 10% by weight of the unsaturated nitrile, and preferably at least 20 % By weight thereof. They can also contain up to 50% by weight of copolymerizable monomers,

«With less than 25.0% preferred and less than 15.0% are most desirable. From the standpoint of highly advantageous technical implementation the monomer formulations contain 30 to 90% by weight, preferably 50 to 80% by weight, of des

fao aromatic monovinyl hydrocarbon and 70 bis 10% by weight, preferably 50 to 20% by weight, of the unsaturated nitrile.

The person skilled in the art knows that the polyblend by polymerizing the monomers in the presence of

hi preformed rubber is produced. It will it is generally believed that some of the polymer formed grafts onto the preformed rubber, since it is generally not possible to use the

Rubber from the polymerized mass with the common rubber solvents to extract in rubber extraction processes that are conventional be used in industry, even if a certain amount of the rubber polymer is not in actual chemical bond with the polymer may be present.

Since 100% grafting efficiency is usually not achievable, at least part of the in The presence of the preformed rubber polymerized monomers are not chemically bonded to it, so to form a matrix for the graft copolymers. This part can depend on the ratio the monomers to the rubber, the special monomer formulation, the nature of the rubber and the polymerization conditions can be increased or decreased. Generally without Inclusion of copolymers made from rubber with material from the graft polymerization reactions compounded to obtain the desired composition.

Any conventional polymerization method can be used to effect the polymerization of the ungrafted To effect mixed polymer, d. That is, processes in bulk, suspension and emulsion can be used or combinations thereof can be used. Such working methods are already known and will be also described below with regard to the graft copolymerization reactions.

The rubbers on which the copolymer is applied during the polymerization in their presence Diene rubbers are diene rubbers which can be grafted on, in which case they form the base of the graft copolymers or mixtures of diene rubbers, d. H. any rubber-like polymers (a polymer with a freezing temperature not above 0 ° C, preferably not above -20 ° C, determined according to the ASTM test D-746-52T) of one or more conjugated 1,3-dienes, for example butadiene, isoprene, piperylene, Chloroprene and the like. Such rubbers include homopolymers and copolymers of conjugated 1,3-dienes with up to an equal amount by weight of one or more copolymerizable, monoethylenically unsaturated monomers, such as aromatic monovinyl hydrocarbons, for example

Styrene,

an aralkylstyrene, such as

o-, m- and p-methylstyrene,

2,4-dimethylstyrene, the

Aräthylstyrenes,

p-tert-butylstyrene and the like,

an alpha-alkylstyrene, such as

alpha-methylstyrene,

alpha-ethylstyrene,

alpha-methyl-p-methylstyrene and the like,

Vinyl naphthalene and the like,

aromatic aromatic mono-vinyl hydrocarbons, for example

o-, m- and p-chlorostyrene,

2,4-dibromostyrene,

2-methyl-4-chlorostyrene and the like,

Acrylonitrile,

Methacrylonitrile,

Alkyl acrylates, for example

Methyl acrylate,

Butyl acrylate,

2-ethylhexyl acrylate and the like,

the corresponding alkyl methacrylates,

Acrylamides, for example

Acrylamide,
Methacrylamide,

N-butyl acrylamide and the like,

unsaturated ketones, for example

Vinyl methyl ketone,

Methyl isopropenyl ketone and the like,
κι alpha-olefins, for example

Ethylene,

Propylene and the like,

Vinyl pyridines,

Vinyl esters, for example
ι -, vinyl acetate,

Vinyl stearate and the like,

Vinyl and

Vinylidene halides, for example the

Vinyl and
Vinylidene chlorides and bromides and the like.

The rubber may contain up to about 2% of a crosslinking agent, based on the weight of the or of the rubber forming monomers, however, the crosslinking agent may have problems in view of the above on the dissolution of the rubber in the monomers for the graft polymerization reaction, in particular for a polymerization reaction in bulk or in suspension. It can also be an excess of jo crosslinking agents lead to a loss of rubber properties. The crosslinking agent can any of the agents conventionally used for crosslinking diene rubbers, for example

j-, divinylbenzene,

Diallyl maleate,
Diallyl fumerate,
Diallyladipate,
Allyacrylate,

Allyl methacrylate,

Diacrylates and
Dimethacrylate from
Polyhydroxy alcohols, for example
Ethylene glycol dimethacrylate and the like.

A preferred group of rubbers consists essentially of 75 to 100% by weight of butadiene and / or Isoprene and up to 25% by weight of a monomer selected from aromatic monovinyl hydrocarbons, for example styrene, and unsaturated nitriles, for example acrylonitrile, or mixtures of that. Particularly advantageous substrates are butadiene homopolymer or a copolymer of 90 to 95% by weight of butadiene and 5 to 10% by weight of acrylonitrile or styrene.

Various methods are commonly used to polymerize rubber monomers, which includes bulk, suspension and emulsion polymerization. The emulsion polymerization can

bo used to make a latex emulsion, which can be used as a basis for emulsion polymerization of the graft copolymer.

The graft copolymers are prepared by adding monomers cies copolymers in the presence

b5 of the preformed rubber base polymerized are, generally according to conventional graft polymerization methods, including polymerization in Suspension, in emulsion or in bulk, where

combinations of these are also possible. In such graft polymerization reactions, the preformed Rubber pad generally dissolved in the monomers and this mixture is polymerized to to chemically bond at least part of the copolymer to the rubber base or to it to graft. Depending on the ratio of monomers to rubber base and cbn polymerization conditions it is possible both the desired degree of grafting of the copolymer on the rubber base and the polymerization of to achieve ungrafted copolymer to create part of the matrix at the same time.

The amount of the mixed polymer layer grafted onto the base for the graft copolymer Sat with large particles can range from just 10 parts by weight per 100 parts of base to 250 parts vary per 100 parts or even higher, the graft copolymers with small particles must but with a ratio of support to support of at least 50: 100, preferably of at least 70: 100 can be grafted to a high degree, the ratio also reaching 250: 100.

To minimize the need for extra equipment, an emulsion polymerization process may desirably be used to make both sizes of graft copolymer components, as well as ungrafted copolymer or crystal product for use as a matrix if required. It can be seen that an emulsion process is required to produce the small particle graft copolymer. In general, the particle sizes of the graft copolymer can be varied by varying the size of the rubber backing used. ie below about 0.2 μ, can be converted into cream form by the use of polyvalent metal salts or acidified in order to achieve the agglomeration of a number of the small rubber particles into a larger mass. During the grafting reaction, the polymerizing monomers graft onto this agglomerate and create In addition, inoculation methods can be used during the polymerization of the rubber and / or during the latex polymerization of the graft copolymer in order to vary the size of the particles produced in this way rbeitsweisen be used in bulk or in suspension ^r> <> to prepare the big Pfropfmischpolymerisatteilchen.

However, different polymerization processes can be used to make the two different Sizes of graft copolymer particles based on the particular process properties in each case to create. In practice it has proven advantageous to use an emulsion polymerization process for the production of the smaller graft particles and a mass suspension polymerization process for «> Manufacture the larger particles to use as highly spherical particles within one relatively narrow size range can be manufactured. In general, the graft copolymerization of Nature of networking and this can be increased by the choice of procedural conditions to ensure individuality to ensure the graft copolymer.

Both the large and the small particles of graft copolymer components can through Mixtures of two or more separately prepared graft copolymers with different ones Properties are created in order to vary the advantages achieved according to the invention even further. For example, the graft copolymer for the small particles can be a mixed coagulate of two different ones Graft copolymer latices with different ratios of support to support or the Graft copolymers for the large particles can be obtained from two different suspension products with varying ratios from pad to pad.

In an advantageous combination of polymerization processes in bulk and in suspension, the monomers, rubber base and catalyst as well as other optional components are introduced into a suitable reaction vessel and then polymerized in bulk by taking them for a period of about 1 to 48 hours and at a pressure from 0.07 to 7.03 kg / cm ² are heated to a temperature of about 75 to 125 ° C until some of the monomer, generally about 15.0 to 50.0% by weight thereof, has polymerized, conventional agitation during the reaction to aid heat transfer. The time required for this partial polymerization varies depending on the catalyst, the pressures and temperatures used and the specific monomers and their ratios. In general, it is preferred to conduct such a prepolymerization process to convert from about 20.0 to 35.0 percent by weight of the monomer.

Any free radical generating catalyst including actinic radiation can be used. A suitable catalyst for the polymerization of the monomer is preferably introduced, for example the conventional monomer-soluble peroxy and perazo compounds and redox systems. Examples for catalysts are

Di-teri-butyl peroxide,

Benzoyl peroxide,

Lauroyl peroxide, Oelyl peroxide,

Toluyl peroxide,

Di-tert-butyl diperphthalate,

tert-butyl peracetate,

tert-butyl perbenzoate,

Dicumyl peroxide,

tert-butyl peroxydisopropyl carbonate,

2,5-dimethyl-2,5-di- (tert-butylperoxy) -hexane,

2,5-dimethyl-2,5-di- (tert-butylperoxy) -hexyne-3,

tert-butyl hydroperoxide,

Cumene hydroperoxide,

p-menthane hydroperoxide,

Cyclopentane hydroperoxide,

Diisopropylbenzene hydroperoxide,

p-tert-butylcumene hydroperoxide,

Pinane hydroperoxide,

2,5-dimethylhexane-2,5-dihydroperoxide

and the like, as well as mixtures thereof.

The catalyst is generally used in an amount ranging from 0.001 to 1.0 weight percent and preferably on the order of 0.005 to 0.5% by weight of the polymerizable material, which is of the Monomers and the desired polymerization

depends on the process.

The syrup created by the partially polymerized formulation is then mixed with water in the presence of a suspending agent, for example the acrylic acid / acrylate copolymers described in U.S. Patents 29 45 013 and 30 51 682. Additional dispersing aids can also be added to obtain the desired suspension of the syrup in water. The suspending agent is preferably added to the water, although it can also be added to the monomers ab initio or during the initial polymerization. This suspension is agitated and heated to a temperature of about 75 to 200 ^° C. for a period of time from 1 to 48 hours in order to obtain essentially complete polymerization of the monomers therein. Such a further polymerization is preferably carried out at a temperature of about 100 to 170 ^° C. for a period of 1 to 20 hours, depending on the catalyst used and its amount. After practical completeness of the polymerization reaction any unreacted monomers or volatile residue components are stripped off and the polymer beads are recovered by centrifugation, washed and 2 ^r> dried.

Alternatively, the monomers and the rubber pad can initially be suspended in water and the entire polymerization reaction can be carried out in suspension. In each procedure jo additional monomers, catalyst, and other components are desired in the polymerizable formulation can be introduced at various stages of the polymerization process.

In the emulsion polymerization are r> the monomers and the rubber base using suitable emulsifiers, such as fatty acid soaps, alkali metal or ammonium soaps of high molecular weight alkyl or alkaryl sulfates and sulfonates, like mineral acid salts of long chain aliphatic amines and emulsified in water. Emulsifiers which have been found to be particularly useful are sodium oleate, sodium palmitate, sodium stearate and other sodium soaps. In general, the emulsifying agent is provided in amounts of τ> about 1 to 15 parts by weight per 100 parts by weight of the monomers and water is provided in an amount of about 1 to 4 parts per part of the monomers and also in larger proportions, if greater dilution is required, provided. ίο

If desired, an aqueous latex formed in the emulsion polymerization of the rubber backing can provide the aqueous medium into which the monomers are incorporated with or without additional emulsifying agents and the like. However, the v> rubber may also be dissolved in the monomers and the mixture emulsified, or a latex may be prepared separately therefrom.

Various water-soluble free radical polymerization initiators are conventionally used for emulsion polymerization of the rubber monomer, including conventional peroxy and perazo catalysts, and the resulting latex can be used as the aqueous medium with which the monomers of the <> ^r > Mixed polymer are mixed. In this way, the rubber polymerization catalyst can function in whole or in part as a graft polymerization catalyst. However, additional catalyst can also be added at the time of the graft polymerization. Examples of suitable peroxy catalysts are the alkali metal peroxides, persulfates, perborates, peracetates and percarbonates, and also hydrogen peroxide. If desired, the catalysts can be activated with the formation of redoxy systems. In addition, it can be advantageous to introduce an oil-soluble catalyst, as has been described, for example, above with regard to the polymerization processes in bulk / emulsion. However, other free radical generating catalysts can be used, such as actinic radiation.

The emulsion mixture is then polymerized in an inert atmosphere at temperatures in the range from 20 to 100 ° C. with agitation. Pressures of 0.07 to 7.03 kg / cm ² can be used and the monomers and / or additional catalyst can be added partially or continuously during part of the course of the reaction. The polymerization is continued until practically all of the monomers, ie more than 90% of the monomers, have reacted. The remaining monomers and other volatile components are then distilled out of the latex, which is then dehydrated, washed and dried.

The particle size of the emulsion plug can be determined by inoculation, emulsifier concentration, agitation, Rubber size, coagulation methods and the like can be varied. It can also be agglomeration of the particles are applied to the size of the rubber latex particles or the graft copolymer particles to increase.

For the purposes of the present invention, the average particle size is based on the number average of the particles of the multiple sizes in each graft copolymer. It will be with the Electron microscope made a photograph of a dispersion and the particle size from 200 to 1000 Particles determined to obtain an average particle size.

As mentioned above, the one rubber graft has an average particle size of 0.01 to 0.25 µ, with greater than 75% of the particles in the range of 0.005 to 0.30. The preferred Compositions have an average particle size in the range of about 0.10 to 0.20 microns.

The other rubber graft has an average particle size in the range from 0.70 to 2.5 μ, with greater than 75% of the particles being in the range of 0.6 to 2.6 microns in terms of size. If the As the average particle size increases within the above range, the weight percentage increases the rubber grafting with a large particle size, which is necessary for comparable impact strength, however, the ratio between the two graft components is more critical. In addition, there is an increase in the average particle size above 2.0 μ the tendency that the highly effective The interaction of the large and small particles becomes minimal and the gloss is excessive is diminished and other properties begin to be adversely affected. When the particle size of the large graft copolymer particles decreases below about 0.9 μ, that of them takes for comparable Impact strength required amount increases rapidly and it becomes more difficult to achieve the optimal balance of Maintain properties. As a result, at

the compositions according to the invention a graft copolymer in the form of large particles used with an average diameter not less than about 0.7μ. In the preferred compositions becomes a graft copolymer in the form of large particles with an average particle size from about 0.9 to 1.4μ is used, with greater than 75% of the particles in the range of 0.8 to 1.5μ.

The two graft copolymers can pass through within the ungrafted copolymer matrix different methods can be mixed. The preferred methods are the graft copolymers blended by extrusion or roller milling treatment, with or without Addition of additional ungrafted copolymer, depending on the amount of ungrafted copolymer in the feeds that provide the rubber grafts and that in the mix desired total rubber graft content depends. Alternatively, a mixed latex can be used Grafts of various particle sizes are made and coagulated together to form crumbs create the rubber grafts of the desired two particle size ranges in the desired Proportions included.

In general, the blends can contain from 0.5 to 20.0 percent by weight of the two combined rubber pads contain. When increasing the total amount of rubber, the ratio of larger parts Grafting to total grafting is kept constant, the Izod impact strength generally decreases Composition too, in addition, the viscosity of the mixture increases rapidly and the yield strength, which Tensile strength on failure and the tensile modulus decrease. If the amount of rubber is the same The ratio of large-particle graft copolymer to small-particle graft copolymer increases occurs a certain increase in turbidity, however, there is a decrease in proportion to improvement put a limit to the gloom through a loss of impact properties. The amount of rubber that the composition may contain also depends on the application. In a contact application, for example as a paper coating where a thin layer of the composition is to be applied are those higher amounts of rubber, i.e. 10 to 20% satisfactory. However, if the composition has a thickness should have over several hundredths of a millimeter and / or when not in a contact application Should be used, rubber concentrations are below 10% for satisfactory transparency in a Desired ratio of large to small particles that is optimal for impact properties. As a result the preferred mixtures contain about 2.0 to 10.0 % By weight of the rubber base.

Since the achievement of a balance of properties is desirable and since the size of the large particles generally have the most pronounced influence with a constant total rubber content on properties, the preferred compositions contain a smaller ratio of the Large particle graft to the small particle graft when the size of the large particles increases.

In general, the graft copolymers are present in a ratio that is somewhat related to the desired one Degree of transparency and the total amount of rubber in the formulation, as well as the size of the large ones Graft copolymer particles varied. As mentioned above, the weight ratio falls Rubber base of the small-sized graft copolymer to the rubber base of the large-sized one Graft copolymer in the range from 4.0 to 32.0: 1.0. When the amount of rubber in the composition is increased, the ratio is desirably increased toward the higher end of the range by obtain satisfactory transparency. In the preferred compositions, a ratio of about 15.0 to 30.0: 1.0 applied.

Of course, depending on the intended application and its nature, the composition optional components can be added, such as dyes and pigments. In general, the Incorporation of stabilizers and antioxidants necessary to prevent degradation of the graft copolymer and often to avoid the mixed polymer of the matrix. The stabilizers and

2 (i Although antioxidants can be used at the time of final mixture, but in general it is most advantageous to incorporate this To incorporate components into the graft copolymers after their formation, so as to avoid any degradation or

2j tendency to oxidize during processing and the Keep storage minimal.

The process according to the invention allows the two graft copolymers to be prepared separately and also the separate production of the matrix mixing

J ₁ I polymerizats, wherein the several components can be stored for long periods of time and are only mixed if necessary to form the desired composition. In this way, the rubber concentration, the transparency and the

Γ) Balance of properties by choosing easily variable percentages of the multiple components can be varied.

The following examples, which relate to preferred embodiments, are intended to further the invention

ίο illustrate but not limit. All parts are based on weight, unless otherwise stated.

example 1

Part A:

To 250.0 parts of a butadiene / acrylonitrile mixed polymer latex (93: 7), the 45.0% solids and about Contains 3.25 parts of rubber protection soap as an emulsifier, 330.0 parts of water, 1.0 part of rubber

• -, (i given protective soap and 0.3 parts of potassium persulfate.

From 112.0 parts of styrene, 48.0 parts of acrylonitrile and 1.3 Divide terpinolene, a mixture is prepared, which continuously over the course of about 6 hours to the Emulsion is added while the reaction vessel

-, -> is placed under polymerization conditions.

During the Polymerisationsablaufes the temperature at about 65 to 8O ⁰ C and the pressure at about 0 to 1.05 kg / cm ² are maintained, the total cycle lasting about 8 hours. Same additions of each

0.5 part of protective rubber soap is added to the polymerizing mixture 3 hours and 4 hours after the start of the cycle. Additional persulfate catalyst is added in 5 equal amounts of 0.13 parts each after periods of 1.2 ¹ A, 3 ¹ / 2.4 ³ A

h ^r i and 6 hours added. It is found that the latex contains a graft copolymer with a ratio of pad to pad of about 80: 100 and a particle size (number average) of 0.13 μ.

19 OO

Part B:

A second graft copolymer latex is produced using a butadiene / styrene rubber underlay (90:10). 50.0 parts of a mixture of styrene and acrylonitrile monomers (80:20) are added in the course of 1 'to a latex which contains 100.0 parts of rubber and about 6.0 parts of soap and 0.2 parts of potassium persulfate. / 2 hours given. During the course of the polymerization, the temperature is in the range from 50 to 70 ^° C. and the pressure is in the range from 0 to 1.05 kg / cm ² . After the end of the polymerization, it is found that the graft copolymer has a ratio of pad to pad of about 37: 100 and a particle size of about 0.05 μm (number average).

Part C:

12.5 parts of a soluble butadiene rubber will be dissolved in 26.5 parts of acrylonitrile and 61.0 parts of styrene. For this purpose, a mixture of 0.07 parts of tert-butyl peracetate, 0.05 part of di-tert-butyl peroxide and stabilizers are added. The mixture is stirring heated to about 100 ° C. As a chain transmission center! terpinolene is added.

At 30.0% conversion of the monomers, the partially polymerized syrup is dispersed in 120.0 parts of water, 2.0 parts of styrene and, as a suspending agent, 0.3 part of a copolymer of 95.5 mol% acrylic acid and 4.5 mol% % 2-ethylhexyl acrylate m with a specific viscosity of about 4.0, determined in a 1.0% solution in water at 25 ° C., can be added. The resulting suspension is stirred and heated to polymerize the remaining monomer, cooled, centrifuged, washed and dried to recover the grafted copolymer in the form of small, spherical beads. The ratio of pad to pad is about 0.9 to 1.0: 1.0 and the particle size is about 1.0 μ.

Part D:

The latex of Part A is mixed with the latex of Part B in a ratio of 943: 57 and the combined latex is coagulated, washed and dried to obtain crumbs. This united Latex offers certain advantages in terms of impact resistance when an emulsion graft copolymer, which is relatively low grafted with which high graft material is provided.

Part E:

The crumbs of the combined latices from Part D, the bead product from Part C, and styrene / acrylonitrile crystal copolymer (67:33) are mixed in various amounts to create a range of compositions having various rubber concentrations. A number of test pieces are produced therefrom by injection molding of pieces (A) with a thickness of 1.45 mm and by compression molding of plates (B) with a thickness of 0.38 mm.

These coupons are then taken for turbidity measurements (ASTM D 1003) and readability measurements subject. In the readability test, the imprint is approximately 4.76 mm in the colors black and red applied. A card bearing the imprint is placed on the surface of the facing away from the viewer molded specimen is moved until the imprint can be clearly read and the distance from the The surface facing away from the cartel is measured. The results of the tests on several Compositions are summarized in Table I below.

Tabel

Specimen United Suspensions SAN rubber Gloom. % B. Removable latex pearls crystal 20.0 kcit (Part D) (Part C) Weight% A. 27.5 cm 1 10 90 4th 47.1 29.0 5.97 2 17.5 - 82.5 7th 66.4 32.5 3.48 3 25th - 75 10 75.5 42.1 2.21 4th 8th 6.4 85.6 4th 64.0 45.5 4.44 5 16 11.2 72.8 7th 80.1 60.5 1.90 6th 20th 16 64 10 87.1 63.7 0.787 7th - 32 68 4th 90.6 68.5 0.635 8th - 56 44 7th 97.0 70.5 0 9 - 80 20th 10 98.7 0 10 - - 5 94.1 0

*) This is a formulation of the latex from Part B and SAN crystal, mixed to a rubber concentration of 5%.

From the above test results it can be seen that the highly grafted latex of Part D in In its undiluted state it is very transparent, but loses its transparency when mixed with a crystalline Styrene / acrylonitrile copolymer of essentially the same composition is mixed to reduce the rubber content to levels required for most packaging applications be used. Conversely, the suspension or large-part graft copolymer is also at 4.0 % By weight of rubber is essentially cloudy and the small-particle low graft copolymer is at a rubber concentration of 5.0% cloudy. if

ω), however, the large-part graft product with the in high Measure grafted copolymer is combined in the manner according to the invention, so are relative obtain transparent compositions which are highly suitable for many packaging applications.

f> ^r > net as they allow viewing of the product and full perception of the colors of the product. Since the copolymer, which is grafted to a large extent, is in and of itself not satisfactory

Provides impact properties, this allows the setting the compositions made to measure to meet the requirements of the field of application while there is still relative transparency

Example 2

To demonstrate the balance of properties of the compositions according to the invention and the effect of varying the rubber ratio of the large and small particle graft copolymers becomes a number of compositions produced by the graft copolymers of parts A, B, C and D of Example 1 with a styrene / acryloni-

10

tril crystal copolymer with two different Molecular weights are mixed, the first having an average molecular weight of about 100,000 to 120,000 and the second has an average molecular weight of about 50,000 to 50,000 own. Various compositions are in the form of sheets with a thickness of 0.76 mm and with A composition is extruded to a thickness of 0.33 mm by compression molding into a plate with a Thickness of 0.76 mm transferred

The results of the tests on several compositions are shown in Table II below compiled

Table II

Specimen 0.76 mm 3.5 7.5 0.76 mm 2.3 5.0 0.33 mm - 0.33 mm - - shaped 435 - - foil 75.1 94/6 foil 83.4 94/6 foil - foil 81.3 - 0.76 mm 78.3 63.8 51.0 41.1 plate High Grafting (Part A) 21.4) 600 14.3 *) 642 18.2 9.7 7.5 17.35 7.5 Low Grafting (Part B) - 556 - 611 1.0 0.5 80/20 - 92/8 Suspension grafting (part C) 22.2 10.2 12.0 8.0 SAN crystal (high molecular weight) 2.18 2.18 - 752 620 SAN crystal (low molecular 239 230 68.7 752 536 weight) 39 33 4.4 14.9 Rubber,% w / w 5.0 3.18 Ratio of small-sized rubber 84/16 too large-sized rubber Yield strength, kg / cm ² 492 Tensile Strength at Failure, kg / cm ² 527 Tensile elongation,% 7.8 Izod impact strength, cmkg / cm notch Drop tear strength, cm kg / cm Turbidity,%

*) This high graft copolymer contains only 33% rubber.

Example 3

A blend is prepared by adding 21.4 parts of a highly grafted, small particle graft latex containing 33% rubber with 3.5 parts of the Suspension graft copolymer of Part C of Example 1 and 75.1 parts of the low molecular weight SAN copolymer from Example 2 are mixed. The resulting composition contains 7.5 Wt .-% rubber and has a rubber ratio of small parts to large parts of 94: 6.

This composition is extruded in the form of a sheet material with a thickness of 0.635 mm and the resulting sheet material is then vacuum formed into 450 g cups weighing 10 g. The wall thickness is determined to be 038 mm Resulting cups are transparent with a milky appearance and an imprint is through them readable at long distances. If colored foods are placed in them, keep them their attractiveness and colors and content are completely visible through the walls of it.

809 545/29

Claims (6)

Patent claims: 1. Polymer mixture of a thermoplastic copolymer A) of predominantly at least one vinylaromatic hydrocarbon and at least one ethylenically unsaturated nitrile and two graft copolymers with different particle sizes from a polymer of an aliphatic 1,3-diene as a graft base and predominantly one monovinylaromatic hydrocarbon and one Ethylenically unsaturated nitrile as a graft, namely a first graft copolymer B) which - based on the number average - has an average particle size of 0.8 to 2.0 microns, with at least 75% by weight of the particles in the range from 0.7 to 2.1 microns, and a second graft copolymer C) which - based on the number average - has an average particle size of 0.01 to 0.25 microns, with at least 75 % by weight of the particles in the range from 0.005 to 0 , 30 microns, the graft copolymers having a ratio of graft price to graft base age from 10 to 250: 100 parts by weight and make up 1.0 to 70% by weight of the 2 ^r > total weight and the second graft copolymer makes up 70 to 97% by weight of the graft copolymers, characterized in that the mean particle size of the first graft copolymer B) is 0.7 to 2.5 m microns, the second graft copolymer C) has a ratio of graft price to graft base of 50 to 200: 100, the graft bases together make up 0.5 to 20% by weight of the polymer mixture and the graft base of the) ^r > second graft copolymer C) to the graft base of the first graft copolymer B) has been used in a weight ratio of 4.0 to 32: 1. 2. Polymer mixture according to claim 1, characterized in that the graft base of the Graft copolymers contains at least about 75 wt .-% conjugated diene. 3. Polymer mixture according to claim 1, characterized in that the vinylaromatic carbon 4 ^r > hydrogen and the unsaturated nitrile make up at least 75% by weight of the thermoplastic copolymer A) and the graft price of the graft copolymers B) and C). 4. Polymer mixture according to claim 1, characterized ίο characterized in that the second graft copolymer C) has a ratio of graft price to graft base from 70.0 to 200.0: 100.0. 5. Polymer mixture according to claim 1, characterized in that da3 is the first graft copolymer B) an average particle size of about 0.9 to 1.4 microns and the second graft copolymer C) have an average particle size of about 0.10 to 0.20 microns. 6. Polymer mixture according to claim 1, characterized in that the graft base of the second graft copolymer C) to the graft base of the first graft copolymer B) has been used in a weight ratio of 15.0 to 30.0: 1.0. b ^r > The invention relates to a polymer mixture composed of a thermoplastic copolymer A) from predominantly at least one vinyl aromatic Hydrocarbon and at least one ethylenically unsaturated nitrile and two graft polymers with different particle sizes from a polymer of an aliphatic 1,3-diene as the graft base and predominantly one monovinyl aromatic hydrocarbon and one ethylenically unsaturated Nitrile, namely a first graft copolymer B), which - based on the number average - has an average particle size of 0.8 to 2.0 microns with at least 75% by weight of the particles in the Range from 0.7 to 2.1 microns, and a second graft copolymer C), which - based on the Number Average - Has an average particle size of 0.01-0.25 microns with at least 75% by weight of the Particles range from 0.005 to 0.30 microns with the graft copolymers having a ratio of Graft price to graft base of 10 to 250: 100 and 1.0 to 70% by weight of the total mixture make up and the second graft copolymer makes up 70 to 97 wt .-% of the graft copolymers. From Be-PS 6 73 030 mixtures are known from