WO1999037700A1

WO1999037700A1 - Method for producing rubber-elastic microsuspension (graft) polymers

Info

Publication number: WO1999037700A1
Application number: PCT/EP1999/000305
Authority: WO
Inventors: Graham Edmund Mc Kee; Heiner GÖRRISSEN; Jürgen Koch; Walter Kastenhuber
Original assignee: Basf Aktiengesellschaft
Priority date: 1998-01-21
Filing date: 1999-01-19
Publication date: 1999-07-29
Also published as: EP1049732A1; DE19802094A1

Abstract

Rubber-elastic microsuspension (graft) polymers are produced by (1) dispersing a mixture of constituents A11-A13 whose entire weight amounts to 100 % and water, using a protective colloid in a dispersion of particles whose average diameter is 0.08-100 νm, whereby A11= 30-99.9 wt. % ethylenically unsaturated monomers as constituent A11, A12= 0-20 wt. % cross-linking monomers as constituent A12, A13= 0.1-50 wt. % aliphatic hydrocarbon polymers with a glass transition temperature below 0 °C as constituent A13, (2) polymerizing the droplets with a radical polymerization initiator and optionally (3) by graft polymerization of the mixture obtained in step (2) in the presence of ethylenically unsaturated monomers.

Description

- 1 -

Process for the production of rubber-elastic micro-suspensions (graft) polymers

The invention relates to processes for producing rubber-elastic microsuspension (piTOpf) polymers, such polymers and molding compositions thereof.

The microsuspension polymerization process, as described, for example, in DE-A-44 43 886 and EP-A-0 716 101, makes rubber elastic

Polymer particles, in particular graft copolymers, with a particle size of less than 50 μm are accessible. Such graft copolymers are often used for the impact-resistant finishing of polymer molding compositions, for example based on styrene and acrylonitrile. In addition, such graft copolymers are also used in these molding compositions in order to obtain a matt surface.

DE-A-44 43 886 relates to particulate rubber-elastic graft polymers which are suitable for improving the quality of macromolecular base materials and consist of a plug core with an average particle diameter of 1 to 100 μm and one or more shells. The graft polymers simultaneously increase the impact resistance of non-elastic polymers and act as matting agents.

EP-A-0 716 101 describes thermoplastic molding compositions composed of a matrix copolymer, particulate graft copolymers with an average particle diameter of 0.03 to 1 μm and particulate crosslinked copolymers with an average particle diameter of 0.05 to 50 μm. The molding compositions constructed in this way are impact modified and matted. - 2 -

Furthermore, from H. Kohkme et al. J. Applied Polymer Sei., Vol. 46, pages 1775 to 1784 (1992), to use acrylate graft polymers prepared by an emulsion / suspension polymerization process for impact modification of acrylonitrile / styrene copolymers.

It is an object of the present invention to provide rubber-elastic microsuspension (graft) polymers which impart impact resistance to polymer molding compositions, impart good mattness and color the molding compositions as little as possible.

The object is achieved according to the invention by a process for the production of rubber-elastic microsuspension (graft) polymers

(1) Dispersing a mixture of components All to A13, the

Total weight is 100% by weight

all: 30 to 99.9% by weight of ethylenically unsaturated monomers, the homopolymers of which are preferably rubber-elastic, as component All,

al2: 0 to 20% by weight of crosslinking monomers as component A12,

al3: 0.1 to 50% by weight of aliphatic hydrocarbon polymers with a glass transition temperature of below 0 ° C. as component A13,

in water using a protective colloid to form a dispersion with an average particle diameter of 0.08 to 100 μm,

(2) Polymerization of the droplets with a, preferably hydrophobic, radical polymerization initiator - 3 -

and if necessary

(3) Graft polymerization of the mixture obtained in step (2) in the presence of ethylenically unsaturated monomers.

The invention is also achieved by the microsuspension (graft) polymers thus obtained and molding compositions containing them, and their use in fibers, foils and foam bodies.

The ethylenically unsaturated monomers used as component All in process step (1) are preferably present in an amount of 55 to 99% by weight, in particular 60 to 98% by weight.

All monomers that can be polymerized with free radicals can be used. For example, monomers can be used whose

Homopolymers are rubber. Elastic. The term “rubber-elastic” here preferably means those polymers whose glass transition temperature is below room temperature (25 ° C.), preferably below 0 ° C., particularly preferably below -10 ° C. Examples of such monomers are C ₆ -, preferably C _S - alkyl (meth) acrylates, in particular n-butyl acrylate and / or ethylhexyl acrylate,

Methyl methacrylate, ethyl acrylate, styrene, acrylonitrile, butadiene and isoprene, which can be substituted, derivatives of (meth) acrylic acid such as epoxy and

Amide compounds or mixtures thereof. C- .. _g- are particularly preferred

Alkyl acrylates, especially n-butyl acrylate and ethylhexyl acrylate. Further monomers which can additionally be used as components are found in Ullman's Encyclopedia of Technical Chemistry, 4th Edition, Volume 19, pages 1 to 30 (Verlag Chemie,

Weinheim).

In addition, 0 to 20% by weight, preferably 0 to 15% by weight, in particular 0 to 10% by weight, of crosslinking agents can be used as component A12 in the monomer dispersion

Monomers are present. Examples of such monomers are bifunctional or polyfunctional comonomers such as butadiene and isoprene, divinyl esters of dicarboxylic acids such as succinic acid and adipic acid, diallyl and divinyl ethers of bifunctional alcohols such as ethylene glycol and butane-1,4-diol, diesters of acrylic acid and methacrylic acid with the bifunctional alcohols mentioned, 1, 4-divinylbenzene and triallyl cyanurate. The are particularly preferred

Acrylic acid esters of tricyclodecenyl alcohol (dihydrodicyclopentadienyl acrylate) and the allyl esters of acrylic acid and methacrylic acid.

Component A13 contains 0.1 to 50% by weight, preferably 1 to 45% by weight, in particular 2 to 40% by weight, of aliphatic hydrocarbon polymers with a

Glass transition temperature of below 0 ° C, preferably below -10 ° C before.

Polymers are preferably aliphatic C ₂ . ₁₀ -, preferably C ₃ . ₅ - hydrocarbons used. Examples are polybutenes, poly dienes such as polybutadiene, polyisoprene, ethylene polymers and ethylene copolymers with. Others

Olefins such as C ₃ - ₃₂ - preferably C ₃ . _I0 olefins and with dienes such as butadiene, isoprene, hexadiene, octadiene, norbornene and dicyclopentadiene as well as styrenes. Polybutene, which is a butene / isobutene copolymer, is particularly preferably used.

The molecular weight M _{n of} the polymer of component A13 is generally 250 to 750,000, preferably 250 to 400,000, particularly preferably 250 to 250,000.

The process according to the invention is preferably carried out as follows:

The liquid mixture of the components All to AI 3, which is to be polymerized to the (core) polymer, is mixed with water and a protective colloid. The polymerization initiator is either added at this point in time or only after the monomers have been dispersed, or also after the dispersion has been heated. The heterogeneous mixture becomes sheared by intensive stirring or a dispersion of minute monomer droplets in water is produced by ultrasound at high speed. Intensive mixers of any type, high-pressure homogenizers and ultrasonic devices are suitable for this. The desired particle size within the defined range can be determined, for example, by taking light microscopic images and counting the number of particles which have a specific diameter.

M-in starts the polymerization by heating the dispersion. The reaction, which is then carried out with moderate stirring, during which the droplets are no longer divided, is continued until the conversion, based on the monomers, is above 50%, particularly preferably above 85%. If no subsequent grafting is carried out, polymerization is carried out until the end of the reaction.

When the polymerization of the graft core has ended in stage 2, the reaction in stage 3 is continued in the presence of ethylenically unsaturated monomers to build up the polymer shell in a manner known per se. However, the grafting can also begin when the polymerization conversion of the core monomers is still incomplete and is above 50%, preferably above 85%. In this case, the graft shell and core form a more fluid transition compared to the sharper demarcation of core and shell polymer in the event that the core monomers are initially completely converted.

The graft polymer can have one or more shells. Different shells can have different compositions, the outermost shell should have the same or a similar composition as a matrix polymer into which the graft polymers are to be introduced.

The dispersion of the monomers is usually at a temperature from 0 to

100 ° C, preferably at room temperature. The proportion of all A12 and A13 in the mixture to be emulsified is 5 to 85% by weight, preferably 10 to 80% by weight, particularly preferably 10 to 70% by weight.

The protective colloids suitable for stabilizing the dispersion are water-soluble polymers which coat the monomer droplets and the polymer particles formed therefrom and in this way protect them from coagulation.

Suitable protective colloids are cellulose derivatives such as carboxymethyl cellulose and hydroxymethyl cellulose, poly-N-vinyl pyrrolidone, polyvinyl alcohol and polyethylene oxide, anionic polymers such as polyacrylic acid and cationic polymers such as poly-N-vinyl imidazole. The amount of these protective colloids is preferably 0.1 to 5% by weight, based on the total mass of the monomers. In addition to the protective colloids, low molecular weight surface-active compounds, for example of the anionic or cationic soap type, can also be present. In this case, smaller polymer particles are obtained. Examples of such soaps are sodium, potassium or ammonium salts of sulfonic acids and Cιo- ₃₀ C for ₁₀ - ₃₀ - fatty acids.

Free radical formers are suitable as polymerization initiators, in particular those which are soluble in the monomers and which preferably have a half-life of 10

Have hours when the temperature is between 25 and 150 ° C. For example, peroxides such as dilauroyl peroxide, peroxosulfates, tert-butyl perpivalate and azo compounds such as azodiisobutyronitrile are suitable. Various initiators can be used to produce the graft core and the graft shells. The amount of initiators is generally 0.1 to 2.5% by weight, based on the amount of monomers.

Furthermore, the reaction mixture can contain buffer substances such as NaH ₂ PO ₄ or Na

Contain citrate / citric acid to adjust the pH to remain essentially constant. In addition, molecular weight regulators are generally used in the polymerization, in particular of the monomers which form graft shells - 7 -

such as ethylhexyl thioglycolate or dodecyl mercaptan added.

The polymerization temperature of the monomers for the production of the core is generally 25 to 150 ° C., preferably 50 to 120 ° C. The shells are generally grafted onto the core at a temperature of 25 to 150 ° C., preferably 50 to 120 ° C. The lower limit values of these ranges correspond to the decomposition temperatures of the polymerization initiators used in each case.

The polymer particles obtained in step (1) preferably have a medium one

Particle diameter of 0.08 to 10 μm, in particular 0.1 to 6 μm.

The monomers used for grafting in step (3) are preferably selected from styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, (meth) acrylic acid esters or mixtures thereof.

The invention also relates to an M-crosuspension (graft) polymer which can be prepared by the process described above.

This microsuspension (graft) polymer is suitable for the production of molding compounds or for the treatment of leather, textiles or paper.

A corresponding molding composition according to the invention contains components A to D, the total weight of which is 100% by weight

a: 0.1 to 80% by weight of at least one microsuspension (graft) polymer, as described above, as component A,

b: 20 to 99.9% by weight of a polymer matrix, for example of polyamide, polyester, polyoxymethylene, preferably a polymer of styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, (meth) acrylic acid esters or Mixtures thereof as component B,

c: 0 to 50% by weight of fibrous or particulate fillers or their mixtures as component C and

d: 0 to 30% by weight of further additives as component D.

Preferred quantitative ranges are 1 to 75% by weight for component A, 25 to 99% by weight for component B, 0 to 40% by weight for component C and 0 to 25% by weight for component D. Quantities from 2 to 70 are particularly preferred

% By weight for component A, 30 to 98% by weight for component B, 0 to 30% by weight for component C and 0 to 20% by weight for component D.

The particulate graft polymers according to the invention serve mainly as additives to brittle thermoplastic macromolecular base materials

(Polymer matrix) of component B. On the one hand, this improves their impact strength, on the other hand, due to diffuse reflection (scattering) of the light on the large particles, molding compositions with reduced surface gloss and correspondingly matt molded parts are obtained. Furthermore, the addition of the graft polymers means that the molding composition is not colored, or is colored only very slightly, yellow.

The molding compositions are suitable for the production of fibers, films or moldings.

The rubber-elastic particles are incorporated into the melt of matrix B, so that the molding composition formed is composed of thermoplastic matrix B and the graft polymer particles dispersed therein.

Preferably, the outermost shell of the particles is compatible or partially compatible with the polymer of matrix B. For this purpose, the outer graft shell can consist of the same or as similar a material as the base polymer. - 9 -

For example, if the outer shell is to be relatively hard, intermediate shells made of a less hard material can be recommended. Furthermore, the first hard grafting shell can be followed by a shell made of soft material, for example the core material, as a result of which the properties of the thermoplastic molding compositions prepared from B and the graft polymer particles A and the moldings produced therefrom can often be further improved. The relationships between the nature of the two components in the molding compositions and the material properties correspond, moreover, to those known for the base material and graft polymers, which are characterized by

Emulsion polymerization can be produced.

This also applies to base materials B other than those mentioned, for example polyesters, polyamides, polyvinyl chloride, polycarbonates and polyoxymethylene. In these cases, compatible and partially compatible graft shells can be identified by some

Determine preliminary tests easily.

Compatibility is understood as miscibility at the molecular level. One polymer is considered to be compatible with another if the molecules of both polymers are statistically distributed in the solid state, i.e. if the concentration of a polymer along any vector neither increases nor decreases. Conversely, it is considered incompatible if two phases are formed in the solid state, which are separated from one another by a sharp phase boundary. Along a vector that intersects the phase interface, the concentration of one polymer suddenly increases from zero to 100% and that of the other from 100% to zero.

There are smooth transitions between the two extremes. They are characterized in that a phase boundary is formed, but this is not clear. At the interface, there is mutual partial penetration of the two phases. The concentration of one polymer therefore takes along one - 10 -

Phase crossing vector more or less quickly from zero to 100% and that of the other polymer more or less quickly from 100% to zero. In this latter case, one speaks of partial compatibility, as it often occurs in technically important polymers.

Examples of partially compatible polymers are the pairs of polymethyl methacrylate / copolymer from styrene and acrylonitrile, polymethyl methacrylate / polyvinyl chloride and polyvinyl chloride / copolymer from styrene and acrylonitrile, and the three-phase system polycarbonate / polybutadiene / copolymer from styrene and acrylonitrile.

More information on the concept of compatibility of polymers and in particular the so-called solubility parameter as a quantitative measure is, for example, the Polymer Handbook, ed. J. Brandrup and EH Immergut, 3rd edition, Wiley, New York 1989, pp. VII / 519-VII / 550 refer to.

For graft modification, the graft polymers according to the invention are generally used in amounts of 0.1 to 80, preferably 1 to 75, particularly preferably 2 to 70, especially 3 to 45% by weight, based on the amount of their mixture with the base polymer. Shaped bodies made from such mixtures are highly light-scattering and therefore particularly matt to opaque.

If a matting effect with still high transparency is desired, concentrations of 2 to 10% by weight of the graft polymers are recommended. Since only a relatively small increase in impact strength would result at these low concentrations, conventional, fine-particle rubber-elastic modifiers can be used in the usual amounts for this, minus the amount of the graft polymer according to the invention used as a matting agent.

In addition, opaque polymers which already contain modifying agents which make impact resistant, for example styrene modified with polybutadiene, - 11 -

Acrylonitrile copolymer (ABS), styrene-acrylonitrile copolymer (ASA) modified with polyalkyl acrylate, or styrene-acrylonitrile copolymer (AES) modified with ethylene-propylene-diene polymer (EPDM) can be matted by using the graft polymers according to the invention.

The particles according to the invention achieve a matting effect without noticeably impairing mechanical properties, as can be observed with conventional matting agents such as chalk or silica gel.

The protective colloids used in the production of the core polymers have, because of their higher molecular mass and greater space filling of the molecules, much less effort than the low molecular weight emulsifiers to migrate to the surface of the plastic. High molecular protective colloids are therefore far less likely to exude from a molded part!

In addition, the molding compositions modified with the particles according to the invention and the moldings produced therefrom have the advantages of improved printability and so-called antiblocking properties, ie the surfaces of the moldings “roughened” by the particles do not adhere to one another. This effect, which is due to adhesion, is known, for example, from plastic films. Films containing particles according to the invention and layered on top of one another in a stack can be separated from one another without any problems, in contrast to films which do not contain such particles.

Preferred fibrous or particulate fillers of component C are

Carbon fibers or glass fibers, such as E, A or C glass fibers are used. These can be equipped with a size and with an adhesion promoter. Glass beads, mineral fibers, whiskers, aluminum oxide fibers, mica, quartz powder and wollastonite can also be added as fillers or reinforcing materials.

The molding compositions can also contain additives of all kinds as component D. - 12 -

contain. Examples include lubricants and mold release agents, pigments, anti-hammers, dyes, stabilizers and antistatic agents, all of which are added in the usual amounts.

The molding compositions according to the invention can be prepared according to known methods

Mixing processes are carried out, for example, by incorporating the particulate graft polymer into the base material at temperatures above the melting point of the base material, in particular at temperatures of 150 to 350 ° C. in conventional mixing devices. From the molding compositions according to the invention, films, fibers and moldings with reduced

Produce surface gloss (mattness) and high impact strength. The polymer components do not separate in the films, fibers and moldings.

The invention is explained in more detail below with the aid of examples.

Examples

Component A13 used:

Indopol ^® L-65 and Indopol ^® Hl 00 and H300 are isobutylene-butene copolymers from Amoco. The products have the following molecular weights Mn, measured by gel permeation chromatography (see Bulletin 12-23, "Amoco Polybutenes,

Physical Properties ").

Indopol L-65 Mn = 435

Indopol H-300 Mn = 1330

Particle size distribution measurements

Particle size distribution was determined with a Elzone ^® 280PC device from Particle Data, Elmhurst, Illinois, United States. The D (50) value is given for the following tests. The D (50) value is the value at which 50 volume percent of the particles are larger and 50 volume percent of the particles are smaller than this value.

The D (10) and D (90) values are defined similarly accordingly. - 13 -

example 1

The following batch was stirred under nitrogen with a Dispermat at 7000 rpm for 20 minutes. The Dispermat was from VMA-Getzmann GmbH, D-51580 Reichshof and provided with a 5 cm tooth lock washer.

Approach:

1132.8 g water

166.7 g PVA solution in water (PVA: degree of hydrolysis 88 mol% and has a viscosity as a 4% solution in water at 20 ° C. of 8 mPa / s according to DIN 53015 - Mowiol ^® 8-88 from Hoechst )

816.7 g of n-butyl acrylate

16.7 g dihydrodicyclopentadienyl acrylate

33.3 g Indopol ^® L-65 (4% wt.) 6.25 g of dilauryl

Three of these batches were emulsified and mixed.

100 g of these emulsions were placed in a moderately stirred (250 rpm) glass flask under nitrogen at 65 ° C. and polymerized. The remainder of the emulsion was metered in over a period of 250 minutes. Polymerization was continued for 60 minutes. After that

281.1 g of water and 171.8 g of a 10% Mowiol ^® 8-88 solution in water in the

Approach introduced, followed by 1288.5 g of styrene and 429.5 acrylonitrile, the

The monomers were added as a feed of 150 minutes. After that was

Polymerized for 120 minutes. Average particle size d (50) = 2.2 μm

Example 2

Example 1 was repeated, but with Indopol ^® H 300 instead of Indopol ^® L-65. The D (50) value was 2.4 μm. 14 -

Example V - comparison

Example 1 was repeated, but without the indopole polymer.

The graft polymers of Examples 1, 2 and V3 were incorporated into a polymer matrix (48 parts by weight of graft polymer and 52 parts by weight of polymer matrix) made of poly (styrene and acrylonitrile) of 67:33. The copolymer had a viscosity number of 80 ml / g, determined according to DIN 53726 at 25 ° C., 0.5% by weight in dimemylformamide. The blends were produced by introducing the rubber dispersion into the copolymer. The impact strength according to DIN 53453 at 23 ° C and the color and surface properties of standard small bars were then assessed visually. The results are shown in the table.

table

Propφolymer from notch ^ h toughness, color "(1) surface ^* (2) example Kj7raHeϊ 220 ^o e melt temp, and 6ö ^β C FormtBtrrp

23 ° C

1 19 less yellow than V3 matt

2 24 less yellow than V3 matt

V3 11 more yellow than 1 and 2 half matt

Judged on standard small sticks, sprayed at 280 ° C and 60 ° C mold temperature.

Claims

- 15 patent claims

1. Process for the production of rubber-elastic microsuspension (graft) polymers

(1) dispersing a mixture of components All to A13, the total weight of which is 100% by weight,

all: 30 to 99.9% by weight of ethylenically unsaturated monomers as component All,

al2: 0 to 20% by weight of crosslinking monomers as component A12,

al3: 0.1 to 50% by weight of aliphatic hydrocarbon polymers with a glass transition temperature of below ° C as component A13,

(2) Polymerization of the droplets with a radical polymerization initiator

and if necessary

2. The method according to claim 1, characterized in that component C 8- ₈ alkyl (meth) acrylates are used.

3. The method according to claim 1 or 2, characterized in that as a comm - 16 -

Component A13 polybutene is used, which can be a butene / isobutene copolymer.

4. The method according to any one of claims 1 to 3, characterized in that the monomers used in step (3) are selected from styrene, α-

Methylstyrene, acrylonitrile, methacrylonitrile, (meth) acrylic acid esters or mixtures thereof.

5. The method according to any one of claims 1 to 4, characterized in that component A13 has a molecular weight M _n of 250 to 750,000.

6. Rubber-elastic microsuspension (graft) polymer which can be prepared by a process according to one of claims 1 to 5.

7. Use of a microsuspension (graft) polymer according to claim 6 for

Manufacture of molding compounds or for the treatment of leather, textiles or paper.

8. Molding composition containing components A to D, the total weight of which is 100% by weight

a: 0.1 to 80% by weight of at least one microsuspension (graft) polymer as claimed in claim 6 as component A,

b: 20 to 99.9% by weight of a polymer matrix as component B,

d: 0 to 30% by weight of further additives as component D. - 17 -

9. Use of molding compositions according to claim 8 for the production of fibers, films or moldings.

10. Fibers, films or moldings from a molding composition according to claim 8.