DE1929502C3 - Molding compositions or molded parts based on selectively plasticized homopolymers and copolymers and processes for their production - Google Patents

Description

Certain thermoplastic polymers such as polystyrene and polymethyl methacrylate have known to be due to inadequate mechanical properties, especially inadequate impact strength, limited uses only. The z. Z. known best way to achieve good impact strength and The good hardness of these polymers consists in finely dispersing an elastomer in the hard resin. the Adding a certain amount of an elastomer, such as polyisoprene or polybutadiene, to a hard resin, like polystyrene, can be made by kneading the two ingredients, by mixing the appropriate aqueous Emulsions or by the so-called grafting process.

As a result of the incompatibility of the two types of polymer, the end products obtained in this way consist of a system of two phases, the mechanical properties of which essentially depend on the physical properties of the resin and the elastomer. In view of the properties inherent in rubbers of the polyisoprene or polybutadiene type, the mechanical properties of the elastomeric phase can only be changed to a very small extent by adding, for example, copolymer ABC
Copolymer ABC
Copolymer ABC
Copolymer ABC
Copolymer ABC
Copolymer ABC

+ Homopolymer A
+ Homopolymer B
-I- homopolymer C
+ Copolymer AB
+ Copolymer BC
+ AC copolymer

The molding compositions according to the invention have excellent properties due to selective plasticization phase A or phase B of the above binary or ternary mixtures. at In this selective plasticization, a plasticizer only has an effect on one of the phases A or B, the becomes noticeable by an increase in the plasticity of the phase in question, while the properties the other phase is not or practically not influenced.

The molding compounds and molded parts can be produced by making polymer mixtures from copolymers at least two different monomers and at least one homopolymer of one of the corresponding Monomers treated with a specific plasticizer, which selectively only polymers from one Affected component of the copolymer, and given

If necessary, the mixtures obtained are shaped in the usual way

According to the invention it is a matter of solving a specific problem that is related to the more general; Use of a plasticizer in homogeneous polymer systems has nothing to do with; this is because the segmented copolymers and graft copolymers are known to form multiphase systems made up of microphases, the average dimensions of which can vary between a few 100 Å and a few 1000 Å, while such separated phases do not exist in the case of random copolymers. By selective plasticization of one of these phases of the multiphase systems, namely either the disperse phase formed by one component of the copolymer or the _{closed phase formed by the other> 5} component of the copolymer, it is possible for the first time according to the invention to produce products whose properties differ from those by plasticization of a homogeneous S-polymer system are completely different. For this reason, the use of conventional plasticizers mentioned in connection with general polymerization and copolymerization processes or the products of such processes in the publications of the prior art cannot give the person skilled in the art any suggestion in the direction of the present invention, since in most cases it is random copolymers or mixtures of these random copolymers with homopolymers, as for example in GB-PS 7 34 251 and DT-AS 12 08 071, in which the problems to be solved according to the invention play no role at all, or in general only deal with them employ to add certain substances to the polymers in order to erieichtern their processing, such as DT-AS 12 29 295 and 12 61 669 and US-PS 31 92 178. Other publications mention a large number of plasticizers of the same type, without it but the specific effect only to suggest that a certain plasticizer from the specified class to a specific segmented copolymer or graft copolymer, and as has been found, actually has. This group of publications includes, for example, DT-AS 1247 014. In particular, general statements about plasticizers in reference works cannot convey the teaching of the invention to the person skilled in the art; teaching on technical action imparted to him.

Suitable plasticizers for the purposes of the invention are non-volatile, high-boiling substances which, when added to one of the polymers, increase its softness, flexibility, extensibility and breakage. They lower the glass transition temperature Tg of the polymer and can therefore facilitate its processing. Among the commercially available plasticizers, those are selected which give the polymer a softness and pliability which is maintained at low ( _{) 0} temperature and which have good heat resistance to enable the polymer to be shaped by pressing and injection molding.

Such a specific plasticizer in the sense of

tA K tiHft ΐ VtalihUi £ ΛΩ /

and preferably unlimited compatibility with the polymer to be plasticized. Good tolerance the plasticizer and the phase to be treated generally avoids migration of the plasticizer in the polymer mass. A compatibility of for example at least 50% means that up to at least 50 wt .-% plasticizer, based on the polymer, can be added to a to achieve significant changes in the properties of the polymer. In other words, the proportion of the Plasticizer, based on the polymer to be modified, can be between 0.5 and 100% by weight and even reach values of up to 120 or 150% by weight or even higher values. In general, however achieved good results with plasticizer amounts of 0.5 to 50 wt .-% of the polymer to be modified. at However, low molecular weight polyvinyl chlorides have been found to have plasticizer levels of 10 to 15 % By weight lead to considerable improvements in the mechanical properties even with plasticizers, whose tolerance limit is around 20 to 25%.

In practice, another prerequisite for obtaining good results is that there should be little migration of the plasticizer in the bulk of the polymer being treated. A plasticizer which is highly compatible with the polymer to be modified in the above sense generally fulfills this requirement. Good results are obtained with plasticizers, the molecule of which is itself a polymeric macromolecule. The resistance to migration and exudation of the plasticizer is measured, for example, by keeping samples at 110 ^° C. for 24 hours and at 170 ^° C. for 3 hours. Under these conditions, in the products according to the invention, no significant change in weight and no change in structure is observed even under the microscope.

The molding compositions according to the invention advantageously consist of the homopolymers of styrene and Methyl methacrylate and the corresponding graft copolymers and segmented copolymers. When further advantageous molding compositions according to the invention are the binary or ternary systems, the based on vinyl chloride and styrene. These masses are by known methods for the treatment of Polymers with plasticizers selectively plasticized with a specific selection of the plasticizer.

It was found that for the molding compositions based on styrene and methyl methacrylate in particular Diisobutyl azelate and butyroethyl stearate are suitable according to the invention as specific plasticizers for polystyrene are. Certain plasticizers are also suitable as specific plasticizers for polystyrene in this case Polyester type, for example based on epoxidized soybean oil and polymeric plasticizers the basis of polyvinyl ethers. Mixed polymers are suitable as specific plasticizers for polymethyl methacrylate of alkylene oxides, for example copolymers of ethylene oxide and propylene oxide as well Products of the polyester type, for example based on polymeric adipates.

For molding compounds based on vinyl chloride and styrene, specific plasticizers for PVC are, in particular, hydroabietyl alcohol Ci ₉ H ₃ ICHjOH, diethylene glycol dipelargonate and N-ethyltoluenesulfonamide in the form of the o- or p-derivative or the derivative mixture. In this case, coumarone-indene resins are suitable as specific plasticizers for polystyrene.

Of course, molding compositions based on other monomers can also be used for this purpose specific Weiehmarhpr hpropct ^ llt iuorHen

5 J €

The invention offers particular advantages for thermo- products that have a very good hardness and a plastic mass. It enables the production of smooth and shiny surface and high end products that have a resin and an impact resistance. These products are suitable for an existing elastomer system, and in particular for the production of molded parts through which the mechanical properties of the elastomeric 5 presses, extrusions and injection molding.
Phase depending on the type and amount of specific plasticizer The invention is illustrated practically continuously by the following examples. The impact strength of the products was constantly changing and, as a result, certain products could be adjusted to pressed values using the Charpy method. In this way test rods were determined which had a mean cross-section, a clear, transparent or opaque profile of 0.17 cm ² .

example 1

This example illustrates the application of the plasticizer made without. The received

Invention on the selective plasticization of binary 1 ₅ results are given in Table I and indicated by circles in

Polymer systems composed of a segmented copoly- F i g. 1 shown graphically. The ordinates in

mers and a homopolymer. The impact strength expressed in cmkg / cm ^{2 and as abscissa}

binary system consists of polymethyl methacrylate se from left to right decreasing the proportions of the

(PMM 28) with a molecular weight of 40,000 and copolymers that are 50% soft with diisobutyl azelate

contains a segmented copolymer made from styrene and polystyrene, and, from right to left

Methyl methacrylate (Cop 29) with a decreasing molecular weight, the proportions of PMM in the molding compound

weight of 120,000 and one styrene content! of 42%. applied.

Tests of the polymer mass are used for comparison

Table I.

% Cop 29% PMM 28 Impact Strength Vicat Point Shore D Hardness Appearance

cmkg / cm ² ° C

O 100 1.5 OO 107 84 transparent 20th 80 3 104.5 82 transparent 50 50 111.5 68 transparent

The results of tests with a polymer composition with the copoly plasticized with diisobutyl acetate Mers whose polystyrene segment contains 50% plasticizer are given below in Table II and < also in FIG. 1 shown graphically (values represented by crosses).

Table II % PMM 28 Impact strength Vicat point Shore D hardness Look % Cop 29 to 50% softened cmkg / cm ² "C 100 1.5 107 84 transparent 0 80 3 68 79 transparent 20 * 67 7.2 68 78 transparent 33 50 6th 68 78 transparent 50 40 4.8 65 78 transparent 60 25th 3 63 75 transparent 75 0 9 66 72 transparent 100

With the same type of polymer tests were carried out on a molding compound that with diisobutyl azelat contained plasticized copolymers, with 100% plasticizer, based on the polystyrene segment have been incorporated. The results are given in Table III below and graphically in FIG represented (values represented by triangles).

Table III % PMM 28 Blow / iihigkcil
cmkg / cm ² Vicnl point
"C Shore D hardness c Look % Cop 29 to 100%
toilet power 100
80
67
50 1.5
3
4.8
3.6 107
69
71
61.5 84
75
60
60 transparent
transparent
transparent
transparent 0
20th
33
50

The results obtained clearly show that according to the invention clearly transparent products with good Hardness and high impact strength can be obtained.

Example 2

Experiments were carried out with a polymer composition of the same type as that of Example 1. The binary system consisted of polymethyl methacrylate (PMM 24) with a molecular weight of 155,000 and a segmented copolymer of styrene and

Methyl methacrylate (Cop 21) with a molecular weight of 445,000 and a styrene content of 48%.

The styrene segment of the copolymer was plasticized with diisobutyl azelate. The amount of plasticizer was 50% based on the copolymer segment. The results obtained are shown in the table below IV indicated and in F i g. 2 graphically shown in the the impact strength values are plotted as the ordinate and the composition of the polymer mass as the abscissa are.

Table IV % PMM 24 Impact strength Vicat point Shore D hardness appearance opaque % Cop 21 to 50% opaque softened cmkg.'cm ² "C opaque 100 6th 107 84 opaque 0 85 12.6 68 80 opaque 15th 70 10.8 67 76 was plasticized, and “PMM 30th 50 7.2 61 75 50 0 - 50 55 100 Example 3 the polystyrene segment,

Experiments wt'-den with a polymer composition of the The results obtained are below in

made of the same type as that of Example 1. Table V mentioned and in F i g. 3, in which the The system consisted of "Cop 29", which stearate with butoxyethyl 30 depending on the composition (KP 23) is applied in an amount of 50%, based on the tongue of the polymer mass

Table V

% Cop 29 to 50% % PMM 24 Impact strength Vicat point Shore D hardness c Look softened cmkg / cm ² "C 33 67 4.2 71 75 transparent 50 50 6th 85 70 transparent 60 40 > 30 80 66 transparent 100 0 30th 58 60 transparent

Example 4

A polymer composition of the type described in Examples 1 to 3 was subjected to the tests. The polymer system consisted of "Cop 21" with

based on the polystyrene segment, was plasticized, and "PMM 12" with a molecular weight of 590,000.

The results are shown in Table VI below

Butoxyäthylstearat (KP 23) in an amount of 50%, 50 called and in Fi g. 4 shown graphically.

Table VI % PMM 12 Impact strength Vicni-Piinki Shcrc-D-Hiirlc Look % Cop 21 to 50% toilet power cmkg / cm ² "C 75 6th 57.5 78 opaque 25th 60 12.6 69 73 opaque 40 50 16.2 68.5 68 opaque 50 40 > 30 73.5 66 opaque ω

The above examples show that, depending on the products, their mechanical properties

wedge of the type and composition of the Copolymc- <vs by changing the type and amount of

ren, the properties of the homopolymers and the specific plasticizer are set and changed

Composition of the mixture can be a whole range can be obtained
of different, clearly transparent or opaque

Example 5

Tests were carried out with ternary mixtures containing the segmented copolymer "Cop 29" of molecular weight 120,000 with 42% polystyrene plasticized with 50% diisobutyl azelate, and as Homopolymer polymethyl methacrylate »PMM 28« (molecular weight 40,000) and polystyrene »PS 27« (Molecular weight 55,000) plasticized with 50% diisobutyl azelate.

The diagram in Figure 5 shows the results obtained. Points A, B, C at the tips of the triangle each represent the components Cop 29, PS 27 and PMM 28. The numbers in the graph indicate the impact strength in cmkg / cm ² divided by the coefficient 6.11. The diagram shows that maximum impact strength is obtained with a mixture of the following composition:

50% PMM 28,

25% PS 27, with 50% diisobutyl azelate

softened,
25% Cop 29, whose PS phase is with

50% diisobutylazelate is plasticized.

In this diagram, the hardness limit is dash-dotted entered, and the solid curve separates the opaque and clear transparent mixtures.

Example 6

The same system was used as in Example 5, but in this case the polystyrene phase was plasticized with 100% by weight diisobutyl acetate. The results obtained are shown in FIG. 6 shown. The point A represents the copolymer "Cop 29" with a molecular weight of 120,000 and 42% polystyrene, which is plasticized with 100% diisobutyl azelate. The point B represents the polystyrene "PS 27" with a molecular weight of 55,000, the is plasticized with 100% diisobutylazelate. Point C represents the polymethyl methacrylate "PMM 28" with a molecular weight of 40,000.

In Fig.6 it can be seen that the maximum of Impact strength is less pronounced than in the systems of Figure 5 and in the mixtures that are richer in PMM 28. Compared to FIG. 5 it should also be noted that the zone in which the Mixtures are clear, is larger. In contrast, the hardness limit lies more towards the tip C of the triangle postponed.

Example 7

The same system was used as in Example 5, but instead of diisobutylazelate an equivalent amount of butoxyethyl stearate is used as a plasticizer, with a degree of plasticization des Polystyrene "PS 27" of 50% by weight was obtained.

The results obtained are shown by the Annarc diagram in FIG. Point A represents the copolymer "Cop 29" with a molecular weight of 120,000 and 42% polystyrene "PS 27", 90% by weight of which is waxed with butoxyethyl stearate. The point β represents the polystyrene "PS 27" with a molecular weight of 55,000, which is 50% plasticized with butoxyethyl stearate. The point C represents the polymethyl methacrylate "PMM 28" with a molecular weight of 40,000. In comparison of FIGS. 5 and FIG . 7 shows that changing the type of plasticizer shifts the zone in which the molded parts are clearly transparent and the hardness limit.

_s examples

Experiments were carried out with a further ternary system that consists of the following components duration:

1) segmented copolymer of styrene and methyl methacrylate (Cop 21) with a molecular weight of 445,000 and 48% polystyrene, which was plasticized with 50% diisobutyl azelate (point A of FIG. 8).

2) Styrene homopolymer (PS 5) with a molecular weight of 420,000, 50% diisobutyl azelate plasticized (point B of FIG. 8).

3) Methyl methacrylate homopolymer (PMM 24) of molecular weight 155,000 (point C of Fig. 8).

The numbers in the diagram in FIG. 8 give as well

as with the previous ternary diagrams, the values of the impact strength of the various selectively plasticized polymer blends. The dash-dotted curve represents the hardness limit of the mixtures, and the solid curve separates the zone of the clear, transparent mixtures from the zone of the opaque Mixtures. In this example, the molecular weights of the three components (copolymer, PS, PMM) increased with unchanged content of specific plasticizer (50% diisobutylazelate).

In this case, too, a reduction in the transparency zone can be observed, but the increase is beneficial the molecular weights result in a systematic increase in the impact strength, like a comparison from F i g. 8 with F i g. 5 shows.

Example! 9

A ternary system was used, which is similar to the one shown in Example! 8 was essentially analogous, in which, however, butoxyethyl stearate (KP 23) is used as a plasticizer instead of diisobutyl azelate would. The results obtained are shown in the ternary diagram of FIG. This system contained

1) segmented copolymer (Cop 21) of Example 8, in which, however, the polystyrene with 50% KP 23

was plasticized (point A of Fig. 9);

2) Styrene homopolymer (PS 25) with a molecular weight of 172,000, plasticized with 50% KP 23 (Point β of Fig. 9);

3) Homopolymer of methyl methacrylate "PMM 12" with a molecular weight of 590,000 (point C of Fig. 9).

The numbers in Fig.9 represent the impact strength of

It can be seen that these values are higher

can be used as the values with that in Fig. "

shown ternary system can be obtained. the

Use of butoxyethyl stearate (KP 23) as

specific plasticizer in this case has the

(.0 complete suppression of transparency / .onc /.111

Consequence. Only the essential "Cop 21" remains clear

transparent (point A of the triangle).

Example 10

This example concerns selective plasticizing of a polymer mixture which comprises a polystyrene (PS) -Polyvi · nylchlorid (PVC) -GraftmischpolymeVcs and a Vi

contains nyl chloride homopolymer. According to the invention, the selective softening is carried out on the disperse Phase, in this case made on the PVC phase. In this way, impact-resistant polymer products are obtained.

The starting point is a graft copolymer that is produced by deactivating an anionic polystyrene of molecular weight 145,000 with a polyvinyl chloride of molecular weight 72,000 was. By fractionation it was found that the graft copolymer of 91% polystyrene and 9% Polyvinyl chloride. It should be noted that analogous graft copolymers are replaced by cationic Plugs can be obtained.

The above-described graft copolymer of polystyrene and polyvinyl chloride was admixed with 5% by weight of the above-mentioned vinyl chloride homopolymer. The polymer mixture to be treated was obtained on this basis. For the selective plasticization of the PVC phase, a polymeric plasticizer was used, which consisted of a polyester based on sebacic acid and is commercially available. The impact strength is measured on molded parts which have been produced by pressing the polymer mixtures at a temperature between 160 and 165 ° C. With a: 100% amount of plasticizer, based on the PVC in the polymer mixture, molded parts were made with a! Impact strength of 7 cmkg / cm ^{2 was} obtained.

7 blue drawings

Claims (5)

Patent claims: 1. Molding compositions or molded parts, consisting of segmented copolymers or graft polymers at least two different N .omeres and at least one homopolymer of one of these monomers, characterized by a content of a specific for the polymer of one monomer of the copolymers and with this in an amount of at least 20% compatible plasticizer, but the polymer of the other monomer is essentially not affected. 2. Molding compositions or molded parts according to claim 1, characterized by a content of one specific plasticizer to be used in an amount of at least 50% with the plasticizer to be plasticized Polymer of one monomer is compatible. 3. molding compositions or molded parts according to claim 1 or 2, characterized in that they are binary Type include and consist of a segmented copolymer or graft copolymer at least consist of two different monomers and a homopolymer of one of these monomers. 4. molding compositions or molded parts according to claim 1 or 2, characterized in that they are used for ternary type and at least one segmented copolymer or graft copolymer consist of two different monomers and the homopolymers of these monomers. 5. Process for the production of molding compositions and molded parts according to Claims 1 to 4, characterized in that characterized in that one polymer mixtures of copolymers of at least two different Monomer and at least one homopolymer of one of the corresponding monomers with a specific plasticizer treated, which selectively only polymerizates from one component of the copolymer influenced, and optionally the resulting mixtures deformed in the usual way. wise their molecular weight is changed. Another disadvantage of this z. Mixtures currently available their opacity, since in numerous applications clearly transparent plastics with good impact strength are required. The invention was based on the object of providing molding compositions in the form of opaque or clear transparent moldings have a very good hardness, a smooth and shiny Surface and have high impact strength. The solution to this problem is molding compositions or molded parts which consist of segmented copolymers or graft copolymers of at least two different monomers and at least one homopolymer of one of these monomers and are characterized by a content of one specific for the polymer of one monomer of the copolymers and with this in one Amount of at least 20% compatible plasticizer, which, however, has essentially no effect on the polymer of the other monomer. A method for the selective plasticization of segmented copolymers or graft copolymers is described in DT-OS 19 29 503. The molding compositions can advantageously be of the binary type and consist of a segmented copolymer or graft copolymers of at least two different monomers and one homopolymer consist of one of these monomers, d. H. from a mixture of the copolymer AB and a homopolymer one of the types A or B (homopolymer A or homopolymer B). The molding compounds can also belong to the ternary type and consist of at least one segmented copolymer or graft copolymer two different monomers and the homopolymers of these monomers exist, d. H. from a mixture of the copolymer AB, the homopolymer A and the homopolymer B. Furthermore, more than two types of monomer units can also be present in the molding compositions by for example the copolymer contains monomer units A, B and C. In this case they are in the binary The following types of molding compounds are possible: