DK142768B - Process for preparing a heterogeneous, sequence emulsion polymerized acrylate polymer. - Google Patents

Description

(tir \ Rg, OD PUBLICATION 142768 DENMARK "" lnt c, i c os f 262/24 (21) Application No. ^ 52, / 67 (22) Filed on 26 J8J1. 19 ^ 7

Mfl (24) Running day 26. Jail »19 ^ 7 ν '(44) The application presented and _

the disclosure notice published on I y · J SU. I yo I

THE DIRECTORATE OF ^ J

PATENT AND TRADE MARKET (30) Priority requested from it

Feb 9 1966, 526038, US

(71) ROHM AND HAAS COMPANY, Independence Mall Meet, Philadelphia, Penn = sylvania 191Ο5, US.

(72) Inventor: Charles Francis Ryan, 197 Willow Drive, Warminster, Penn = sylvanla, US.

(74) Plenipotentiary in the proceedings:

Th. Ostenfeld Patent Office. A / s._ (54) Process for preparing a heterogeneous, s eleven erulsions = polymerized aerylate polymer.

The present invention relates to a process for preparing a heterogeneous, sequence emulsion polymerized copolymer comprising a first-stage C2-6 alkylerylate polymer and a subsequent step alkylmethaerylate polymer.

From the description to U.S.A. Patent No. 3,041,309 discloses the preparation of similar copolymers by emulsion polymerization in two stages, forming in the first step a rubbery, optionally crosslinked alkylerylate polymer, while in the second step a methyl methaerylate polymer is seeded. The copolymer thus prepared is stated to have physical properties ranging from rigid rubber to hard resin and to be used in the manufacture of shaped articles, either as such or in admixture with rigid styrene interpolymers to obtain products with particularly good outdoor resistance. The known copolymer polymer is further stated to be suitable as a reinforcing agent in certain rubber products and as impact strength modifier in hard, rigid vinyl chloride polymers.

It has now unexpectedly been found that by replacing the last step of the known two-step process with three or more specially selected steps, one can provide a copolymer which, in addition to being suitable for generally the same purpose as the known copolymer, has a special combination of properties that makes it particularly useful for film making.

This is achieved by the invention by (a) polymerizing a first-stage monomer system emulsified in water, which first-stage monomer system primarily comprises a C2-6 alkyl acrylate and from 0.1 to 5% by weight, relative to the other monomer (s) of a cross-linking monomer, the monomer system being such that the polymer product contains at least 80% by weight of C₂2_ alkyl acrylate units and is a rubbery copolymer having a glass transition temperature not exceeding -20 ° C, (b) sequentially setting the resulting aqueous system three or more subsequent step monomer systems, each consisting of at least 80% by weight of C 1-4 alkyl methacrylate optionally in admixture with C 1-6 alkyl acrylate, and sequentially polymerize each of the subsequent monomer systems under conditions which cause association of the polymer molecules formed for particles formed in the previous step or steps, wherein each subsequent step monomer system comprises a g a progressively smaller amount of C₂gg alkyl acrylate and a progressively greater amount of C ^ _4 alkyl methacrylate than the monomer system of the preceding step, and the last-stage monomer system is such that the final-stage polymer has a glass transition temperature of at least 60 ° C, whereby the first-stage polymer constitutes 10 75% by weight of the final copolymer product and the subsequent step polymers constitute 90-25% by weight of the final copolymer product.

The acrylate copolymers prepared by the process of the invention are solid thermoplastic materials which, like the above-mentioned, known copolymers, can be used as impact strength modifiers and processing auxiliary materials in vinyl chloride resins, acrylic resins, styrene resins and other resinous materials; in addition, however, the acrylate copolymers in question are particularly well suited for the production of films and sheets, especially cohesive films which can be applied to various substrates, e.g. by rolling lamination of such a film (or using other prior art), especially on exterior cladding materials or other building products to provide a protective and decorative layer thereon.

The present copolymers, hereinafter referred to by the general term "polymers", are prepared by carefully controlled polymerization carried out in emulsion. In the first test step, a caustic-like uniform crosslinked copolymer is formed by emulsion polymerization of at least one C2-8 alkyl ester of acrylic acid with a small amount of a crosslinking monomer and 0-20% by weight of one or more non-crosslinking comonomers. The polymerization can be carried out using 1-3% by weight of a suitable emulsifier based on the weight of the first stage monomer, and an initiation system, preferably of a redox nature. The copolymerization is usually carried out under such reaction conditions as to produce a first-stage medium to large particle size latex, usually between ca. 400 and approx. 2000 Angstrom in radius. Next, in the presence of the latex produced during the first process step, a mixture containing at least 80% by weight of at least one C1-4 alkyl methacrylate, such as methyl methacrylate, and at least one C2-6 alkyl acrylate is polymerized with at least one other non-crosslinking comonomer. This polymerization is carried out under such conditions that the chains are linked to and / or intimately linked to the poly (alkyl acrylate) cross-linked chains from the first process step. During this second process step additional initiating agents may be added, but no further emulsifier is usually needed, since the polymerization in this step must be carried out so that no new additional particles are produced. Preferably, the monomers used in the second process step are gradually added. After completion of the second process step polymerization, a mixture of a C1-4 alkyl methacrylate and a C2-6 alkyl acrylate is added and then polymerized in the presence of a second process step latex, thereby obtaining an association between and / or intimate connection between the third process step or phase and the pre-made two-stage latexes. Preferably, the monomers are added gradually during the third process step. Here, too, it is not necessary to add emulsifier, since the polymerization must be carried out so that no new additional particles are formed in the main case. However, it is often necessary to use more initiator. By the fourth process step, the monomer mixture preferably contains an adhesion-promoting monomer such as methacrylic acid. Preferably, the monomer used during the last process step is gradually added and polymerized rapidly, thereby obtaining a fixation and storage on the pre-formed latex of the final phase.

The multi-stage sequence emulsion polymerization can be carried out at temperatures between ca. 0 to 125 ° C, and preferably between 30 and 95 ° C. The polymerization medium may contain, in accordance with known practice, a chain transfer agent such as tertiary dodecyl mercaptan, secondary butyl mercaptan and normal dodecyl mercaptan, especially to limit, when desired, the molecular weight of phases or process steps containing alkyl methacrylate. The free radical initiator can be used in effective amount, which varies depending on the monomers, temperature and mode of addition, but is usually about 0.001 - 2.0% by weight at each polymerization step, based on the weight of the monomer portion by up to a maximum of approx. 5% by weight based on the total weight of the monomer portions at the second process step. The resulting solid thermoplastic polymeric product may be isolated from the emulsion by evaporation, by appropriate coagulation and leaching, such as by salt coagulation, by freezing, etc., or may be isolated, e.g. by spray drying.

With respect to the first step reaction components, the alkyl group in the alkyl ester of the acrylic acid may be a straight or branched chain. Polymers formed at the first process step must have a glass transition temperature (Tg) of -20 ° C or below (eg -30 ° C, ^ 40 ° C, etc.). The other non-crosslinking comonomers which may be used to form the optional residue of first-stage reactants (as described above) may be any non-crosslinking monovinylidene monomer interpolymerizable with the alkyl acrylate such as e.g. vinylidene chloride, vinyl chloride, acrylonitrile, vinyl esters, alkyl methacrylic acid esters, styrene, ring alkyl styrenes such as o-, m- and p-methylstyrenes, α-alkyl styrenes such as α-methylstyrene. A crosslinking bi- or polyfunctional monomer is used during the first process step to crosslink alkyl acrylate monomers in an amount of between 0.1 and 5% by weight based on the other monomer (s), preferably between 0.5 and 1, used. 5% by weight. The crosslinking monomer should conveniently have the ability to crosslink the alkyl acrylate in a uniform manner. Cross-linking monomers of this ability are those which are uniformly incorporated into the polymerization reaction product and are independent of the reaction course. In other words, the rate of consumption thereof is virtually the same as that of the primary monomer present, the alkyl acrylate. It is therefore preferred to use as an crosslinking monomer an alkylene glycol diacrylate such as ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate and propylene glycol diacrylate. Other crosslinking monomers such as divinylbenzene, divinyl adipate or diallylphthaiate may also be used. As used herein, the term "polyfunctional cross-linking monomer" is understood to mean difunctional or bifunctional cross-linking monomers, i.e. monomers containing two reactive groups in the polymerization, and cross-linking monomers containing more than two reactable groups in the polymerization.

The crosslinked, rubbery, first-stage product constitutes 10 -75% by weight of the final copolymer product, with the remaining weight, i.e. 90% to 25% by weight is distributed among the polymers of the subsequent steps.

As an example of the gradually decreasing amount of alkyl acrylate, the second process step may contain approx. 10 to approx. 60% by weight of alkyl acrylate, the balance of 90-40% being alkyl methacrylate; the third process step may contain approx. 5-40% by weight of alkyl acrylate, the remainder, 95-60%, being alkyl methacrylate. At the fourth stage of the process, 0 to approx. 20% by weight C2-6 alkyl acrylate and 80-100% by weight C1-4 alkyl methacrylate. Typically, each subsequent process step will contain approx. 1/10 to approx. 3/4 of the amount of alkyl acrylate, e.g. butyl acrylate, which is used in the immediately preceding process step.

A major limitation on the nature of the final or hard step is its glass transition temperature (Tg). The glass transition temperature of the polymer produced at the last process step must be at least 60 ° C. Preferably, the last process step monomer contains a smaller amount, i.e. up to 20, usually 1-20 parts per 100 parts of last-step ester monomers, by an adhesion promoter containing acid groups. Examples of these are α, β-unsaturated acids such as acrylic acid, methacrylic acid, as well as unsaturated dicarboxylic acids such as maleic acid and fumaric acid.

At each of the subsequent process steps, a portion of the alkyl methacrylate or alkyl methacrylate-alkyl acrylate mixture may, up to a maximum of about 20%, is replaced by one or more non-cross-linking comonomers which can be interpolymerized therewith. Such comonomers include e.g. vinylidene chloride, vinyl chloride, acrylonitrile vinyl esters, styrene, ring alkyl styrenes such as o-, m- and p-methyl styrenes, α-alkyl styrenes such as α-methyl styrene.

As stated above, the rubbery cross-linked first stage product constitutes approx. 10 to approx. 75% by weight of the final copolymer product. The rest, i.e. 90-25% by weight may be evenly or evenly distributed on the other process steps, although it is preferred that no single process step product is present in an amount less than 1/5 of the total weight amount of the remaining process steps. products (ie all but the first).

c 142768

ISLAND

A particularly convenient balancing of the properties of the final copolymer product is achieved when the polymerization is carried out in four steps, the second stage monomer system containing 10-60% by weight of at least one C2-6 alkyl acrylate and 90-40 of at least one C1-4 alkyl methacrylate, third stage monomer system. 5-40 weight percent of at least one C 2-8 alkyl acrylate and 95-60 weight percent of at least one C 1-4 alkyl methacrylate, and the fourth stage monomer system contains 0 to about 20% by weight of at least one C2-6 alkyl acrylate and 80-100% by weight of at least one C1-4 alkyl methacrylate.

Hereby, it is preferred that the fourth stage monomer system additionally contains 1-20% by weight based on the total weight of the acrylate and methacrylate monomers, of α, β-ethylenically unsaturated monocarboxylic acid and / or an ethylenically unsaturated dicarboxylic acid.

The presence of such a carboxylic acid has, as explained above, an adhesion-promoting effect.

Although any of the C are methyl methacrylate units. The starting materials required for this are particularly readily available and preferred physical properties are obtained for the finished product.

Many different of the commonly known emulsifiers can be used for the emulsion polymerization of acrylates and methacrylates. It is desirable to use a small amount of emulsifier, preferably less than 1% by weight based on the total weight of the polymerizable monomers used at all process steps. Useful emulsifiers include common soaps, alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate, alkylphenoxypolyethylene sulfonates, sodium lauryl sulfate, salts of long chain amines, salts of long chain carboxylic acids and sulfonic acids, etc. In general, the emulsifiers must be compounds containing hydrocarbon groups of 8-22 carbon atoms bonded to highly polar solution groups such as alkali metal and ammonium carboxylate groups, sulfate half-ester groups, sulfonate groups, phosphate partial ester groups and the like.

The polymerization medium at each process step preferably contains an effective amount of a suitable oil-soluble, water-insoluble, free-radical-forming polymerization initiator which is activated either thermally or by an oxidation-reduction (or redox) reaction. Preferred initiators are those resulting from redox reactions, thereby obtaining an efficient polymerization at moderate reaction temperature. Examples of suitable initiators or combinations thereof are cumene hydroperaxide sodium sodium tabisulfite, diisopropylbenzene hydroperoxide sodium formaldehyde sulfoxylate / tertiary butyl peracetate sodium hydrosulfite, cumene hydroperoxide sodium formaldehyde sulfoxylate. Water-soluble initiators may also be used but are less desirable; examples of such initiating agents or combinations are sodium persulfate, potassium persulfate sodium formaldehyde sulfoxylate.

The physical appearance of the polymeric product produced by the sequence emulsion polymerization of the invention, e.g. in the above-described 4-step process, a rubbery, uniformly cross-linked first-stage product or phase is attached or intimately linked to a number of subsequent phases or stages. By microscopic examination and from data of minimum film-forming temperature, it appears that gradual transition forms from first-stage product to fourth-stage product are obtained by applying the phases from the inner side to the outer side or the surface of the polymeric particles. Each subsequent step is associated with the existing latex by combining at least some penetration, encapsulation or layering. Where it for example. in the case of a 4-stage polymerization product, the second stage is associated with or intimately connected to the first stage with only a light stratification, while the third stage is associated with or intimately connected to a second stage material of greater stratification, and the fourth step, ie the final or hard phase, is associated with or intimately associated with third stage material with substantially more layering and with relatively little penetration of the previous third stage material. These transition-stage effects are believed to be due to the particular combination of properties of the polymeric product, especially when used as a film material. Thus, when the polymeric product is used for film formation, this material has excellent elongation properties and at the same time excellent resistance to blocking. Extruded and blown films made from the polymers in question typically have at least 35% elongation (and up to 90%), making it possible to produce film laminates that can be bent and machined over sharp edges without in any way damaging them. Furthermore, these films have excellent resistance to blocking, i.e. decreased tendency for adhesion, e.g. film-film and film-metal samples show a resistance to adhesion at temperatures up to 65 ° C and above.

142768 δ

In addition, films of σοροlymers made by the process of the invention can be applied to non-metallic substrates such as wood fiber boards, asbestos cement, plywood, as well as timber and roofing materials. It will often be appropriate to cover the substrate in advance. or the substrate with an adhesive, especially in the case of metallic substrates, although the films as listed below can be laminated directly to aluminum with or without the use of external adhesives. The films are not limited in their use to special adhesives, as any commercially available metal-plastic adhesive or non-metal-plastic adhesive may be used. Examples of suitable adhesives are organic solvent solutions of terpolymers of methyl methacrylate, ethyl acrylate and methacrylic acid in the weight ratio of 55-65 parts of methyl methacrylate, 35-39 parts of ethyl acrylate and 1 to 5 parts of methacrylic acid or those of the trade name Armstrong Cork Company under the trade name "J-1199". adhesives containing a vinyl chloride vinyl acetate copolymer, an acrylic polymer and an epoxy resin in an organic solvent such as toluene and methyl ethyl ketone.

Films and sheets prepared from the polymers obtained by the process of the present invention may vary in thickness between 0.0072 cm and 0.360 cm and preferably between 0.0072 and 0.072 cm. Generally, such films are prepared by extrusion and blowing techniques of a kind known per se, e.g. at temperatures between ca.

185 and approx. 260 ° C. The films can also be made by compression molding. In the case of clear films, it is not necessary to add additional ingredients. If color or opacity is desired, the films may be formulated to contain fillers, pigments, dyes and stabilizers. Fillers that can be used are e.g. ground and precipitated calcium carbonate, barites, diatomaceous earth, various clay soils. Examples of pigments that can be used are titanium dioxide, cadmium red, chromium orange and chromium yellow, phthalocyanine green and blue.

The heterogeneous multi-stage polymers obtained in accordance with the invention can be used, as indicated above, to improve the machining and impact properties of vinyl chloride resins and styrene resins as well as acrylic resins and other resinous materials by mixing them. Such mixtures typically contain 75-95% by weight of the resin or resinous material and 25-5% by weight of the multi-stage heterogeneous polymer.

The multi-stage heterogeneous emulsion polymer prepared according to the invention includes four-stage, five-stage and up to six or multi-stage products, suitably has melt index values between 0.01 and 20, and preferably between 0.75 and 3.5. The melt index is the number of grams of polymers that will flow through a 0.19 cm aperture at 200 ° C and a pressure of 14 kp per minute. over 10 minutes under the test conditions set forth in ASTM D 1238-57 T. The polymers also conveniently have minimum film forming temperatures (MFTs) of approx. 75 to approx. 100 ° C.

The process according to the invention will be further elucidated in the following by examples and tables, where all parts and percentages are parts by weight and percentages, unless otherwise stated.

Example 1

Preparation of four step heterogeneous polymer and film thereof.

To a reaction vessel equipped with a stirrer, thermometer, nitrogen purging device, monomer addition and reflux inlet opening was added 1000 parts of deionized water, 41.6 parts of a 10% solution of sodium octylphenoxypolyethoxysulfonate emulsifier (containing two ethylene oxide acetic acid groups) , 139 parts butyl acrylate, 1.39 parts 1,3-butylene glycol diacrylate and 0.12 parts diisopropylbenzene hydroperoxide. The mixture was degassed vigorously with nitrogen for 90 minutes at 30 ° C, and while degassing over the surface was continued, a solution of 0.015 parts of sodium sulfoxylate formaldehyde in 20 parts of water was gradually added and the polymerization of the first-stage monomers was carried out for substantially completion over about 30 minutes. . 30 minutes. The reaction mixture was then heated to 85 ° C, at which time a solution of 0.14 parts of sodium sulfoxylate formaldehyde in a small amount of water was added, followed by gradual addition at 85 ° C over 1 hour of a mixture of 0.28 parts of diisopropylbenzene hydroperoxide, 55 , 4 parts butyl acrylate and 83.2 parts methyl methacrylate. After the monomer addition was complete, the mixture was stirred for 30 minutes at 85 ° C and the polymerization of the second-stage monomers proceeded to complete completion.

The third process step proceeded under conditions similar to the second process step. After adding a solution of 0.14 parts of sodium sulfoxylate formaldehyde in 20 parts of water, a mixture of 14.1 parts of butyl acrylate, 125 parts of methyl methacrylate, 0.277 parts of diisopropylbenzene hydroperoxide and 0.35 parts of n-dodecylmercaptan was added over 1 hour. After the monomer addition was complete, the temperature was maintained at 85-90 ° C for 30 minutes and the third stage of the polymerization was completed. Then, a solution of sodium sulfoxylate formaldehyde 10 142768 (0.277 parts in 1 part water) was added, then at 85-90 ° C over 1 hour a mixture of 2.77 parts butyl acrylate, 136 parts methyl methacrylate, 5.5 parts was added. methacrylic acid and 1.1 parts diisopropylbenzene peroxide and 1.39 parts t-dodecyl mercaptan. After the addition was complete, the reaction temperature was maintained at 85-90 ° C for 1 hour and the polymerization of the fourth-stage monomers was completed. The emulsion was then cooled and the polymeric product was isolated from the emulsion by adding equal volume of water containing 5% sodium chloride, then filtering and drying carefully in a vacuum oven. The polymer product had a melt index of 0.8.

The polymer was extruded and blown to 0.0072 cm thick film. The 2 free films had the following properties: Tensile strength 361.9 kg / cm machine 2 direction (M), 388.5 kg / cm in transverse direction (T), extension 51% M, 2 2 43% T, modulus of elasticity 18,830 kg / cm M, 20,930 kg / cm T (according to ASTM-D 882-64T).

The film was laminated to aluminum and the properties of the laminate measured. The dry adhesion was excellent and the machinability properties judged as the laminate's ability to withstand cracking by strong bending were also excellent, as was the case for the impact strength at temperatures as low as -18 ° C. There was no blocking of flat-to-flat or flat-to-back film laminates at 60 ° C and only minor blockage of flat-to-flat laminates at 82 ° C, while the pressure resistance at these temperatures was also excellent.

The film can be laminated directly to aluminum, i.e. without the use of external adhesives, in which cases good dry adhesion is obtained. When external adhesives are used, a particularly excellent wet and dry adhesion, such as e.g. by applying the substrate to the commercial agent under the trade name "Armstrong J-1199". The film can be pigmented and filled with fillers. Furthermore, it should be noted that the use of 15% TiO 2 or other pigment gives a film of somewhat lower impact strength at -18 ° C, but the properties of films laminated to steel or aluminum are still excellent.

Example 2

Preparation of Five-Step Copolymer

To a reaction vessel equipped with a stirrer, thermometer, nitrogen purging device, inlet port for monomer addition, reflux was added 1000 parts of ionized water, 33.3 parts of a 10% solution of sodium octylphenoxypolyethoxy sulfonate emulsifier (containing 2 ethylene oxide acetic acid), 0.11 parts , 111.2 parts butyl acrylate, 1.11 parts 1,3-butylene glycol diacrylate and 0.096 parts diisopropylbenzene hydroperoxide. The mixture was degassed with nitrogen and as the surface gasification continued, a solution of 0.012 parts of sodium sulfoxylate formaldehyde in 20 parts of water was gradually added thereto, and the copolymerization of the first-stage monomers was completed in about 10 minutes. 30 minutes. The reaction mixture was heated to 85 ° C, at which time a solution of 0.11 parts sodium sulfoxylate formaldehyde in 20 parts water was added, followed by gradual addition at 85 ° C over 1 hour of a mixture of 0.275 parts diisopropylbenzene hydroperoxide, 66 , 7 parts butyl acrylate and 44.5 parts methyl methacrylate. After the monomer addition was complete, the mixture was stirred for 30 minutes at 85 ° C and the polymerization of the two-stage monomers was completed. Third steps were carried out with a solution of 0.11 parts of sodium sulfoxylate formaldehyde in 20 parts of water, a mixture of 44.5 parts of butyl acrylate, 66.7 parts of methyl methacrylate and 0.275 parts of diisopropylbenzene hydroperoxide, which was added over approx. 1 hour. After the monomer addition was complete, the temperature was maintained at 85-90 ° C for 30 minutes and the third-stage polymerization was completed. A fourth process step was performed by addition under conditions similar to the third process step. After addition of 0.11 parts sodium sulfoxylate formaldehyde in 20 parts water, a mixture of 11.1 parts butyl acrylate, 100.1 parts methyl methacrylate, 0.275 parts diisopropylbenzene hydroperoxide and 0.28 parts n-dodecyl mercaptan at 85-90 ° C was added. of approx.

1 hour, and the polymerization was completed in a further 30 minutes. Then 0.222 parts of sodium sulfoxylate formaldehyde in 20 parts of water were added, and a fifth process step involved gradually adding 2.25 parts of butyl acrylate, 109 parts of methyl methacrylate, 5.5 parts of methacrylic acid, 1.1 parts of t-dodecylmercaptan and 0.88 parts of diisopropylbenzene. at 85-90 ° C over 1 hour. After the addition was complete, the reaction mixture was maintained at 85-90 ° C for an additional 1 hour and the polymerization of the fifth step monomers was completed. The emulsion was cooled and the polymeric product isolated by coagulation with saline, then the product was filtered and dried. A free film formed from the polymer product had properties similar to those obtained by the four-step polymer product of Example 1.

Example 3

By using ethyl acrylate instead of butyl acrylate in Example 1, a polymer product having the same general properties as the product of Example 1 is obtained. The only notable difference between the properties of the two products is that the product prepared according to Example 1 had slightly better physical properties at low temperature, but conversely it had a little less resistance to solvents (gasoline).

Example 4

Similarly, the use of 2-ethylhexyl acrylate instead of butyl acrylate in Example 1 yielded a product which was slightly softer but had better physical properties at low temperature.

To obtain a product having the same properties as the product of Example 1, it was found that generally lower concentrations of 2-ethyl-hexyl acrylate than of butyl acrylate were used.

Example 5

Repeating Example 1 but using isopropyl or isobutyl methacrylate, the only difference to the product of Example 1 was that the product produced was slightly softer.

Using the method of Example 1, a variety of four-stage polymeric products were prepared; the ratios of the monomers constituting these products are listed below in Table I.

Table I

1st process step 2nd process step 3rd process step 4th process step monomeric butyl monomer butyl monomer butyl monomer butyl monomer

Product acrylate, 1,3 acrylate, methyl acrylate, methyl acrylate, methyl identifibutylene glycol methacrylate methacrylate methacrylate, methacation_diacrylate_acrylic acid_A 30: 0.3 9.3: 14 2.3: 21 0.5 : 22.8: 1 B 35: 0.35 8.7: 13 2.2: 19.5 0.4: 21.3: 1 C 40: 0.4 8: 12 2: 18 0.4: 19 , 6: 1

The properties of the polymeric products identified by the symbols A, B and C above are listed below in Table II.

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Table II

Product- The Polymeric Melting Properties of extruded and blown film identifi min. index _ (0.0072 cm) (x) _ cation film forming Tensile strength kg / cm ^, Extension module kg / cm ^ P extrusion machine%, extrusion (xl0-5) C direction / transverse machine direction / extrusion direction transverse machine direction. / direction transverse direction A 80 0.8 297.5 / 331.8 57.2 / 52 0.146 / 0.165 B 80 0.7 263.2 / 312.9 69.1 / 62.3 0.121 / 0.144 C 84 0, 44 210.7 / 277.9 65.1 / 45.5 0.085 / 0.111 (x) Free films made from polymers A, B and C all have excellent block resistance - no significant blocking occurs at temperatures up to 65 ° C when the film is subjected to a pressure of 0.42 kg / cm for 16 hours.

Using the method of Example 1, a variety of four-stage polymeric products were prepared; the ratios of the monomers constituting these products are listed below in Table III.

Table III

1st stage monomers 2nd stage monomers 3rd stage monomers 4th stage monomers butyl acrylate: butyl acrylate: butyl acrylate: butyl acrylate:

Product styrene: 1,3-butystyrene methyl styrene: methyl methyl methacrylate: identifierlylcoldiacryl methacrylate methacrylate methacrylic acid cation lat _____ D 21.25: 3.75: 0.25 10: 1.9: 13.1 2, 5: 0.25: 22.25 0.5: 24.5: 1 E 21.25: 3.75: 0.25 10: 2.5: 12.5 2.5: 0.5: 22 0, 5: 24.5: 1

The properties of the polymeric product identified by symbols D and E above are listed below in Table IV.

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Table XV

Product- The Polymeric Melting Properties of extruded and blown film identifi min. index _ (0.0072 cm) (x) _ Cation tensile strength kg / cm ^, Extension Module kg / cm ^ p extrusion machine%, extrusion (x10-5) ° C direction / transverse machine direction / extrusion direction transverse machine direction / direction transverse direction D 85 1.1 327.95 / 346.22 48.8 / 10.6 0.151 / 0.196 E 84 2.3 324.10 / 338.10 52.6 / 30.9 0.153 / 0.177 (x) Free films made from polymers D and E all have excellent blocking resistance - no appreciable blocking occurs at temperatures up to 65 ° C when the film is subjected to a pressure of 0.42 kg / cm for 16 hours.

A variety of film laminates were prepared with films formed from the polymeric products of the invention. The substrate was chromate-pretreated C'Alodine 1200 S. 24-aluminum. The film was in each case a thickness of 0.0072 cm and rolled on the substrate, covered with an outer adhesive, at a temperature of about 205 ° C. which, below in Table V, is designated "Ex. 1, A, B and C ", contain 13 parts of TiCl 2 pigments per 87 parts of polymer; the films D and E are clear and unpigmented. The films are identical in composition to the corresponding products listed above in the tables. I and III.

Table V

Properties of film laminates

Film T-bend x Impact Strength (kpm)

Identification Manufacturing Room temp

cation Substrate

From Example 1 Aluminum 1/0 52/29 - A Table I - 0/0 52/40 - B Table I - 0/0 58/40 - C Table I - 0/0 76/40 - D Table III - 1 / 0 - E Table III - 0/0

Claims (2)

* T-bend fabrication is a measure of the laminate's ability to stand the fabrication. A first bend is made over a 0.3 cm stand and the bend is completed between the jaws in a vice to form a 180 ° bend. The edges of the bends were examined under a 25 x microscope and evaluated from 0 to 10 corresponding to 0 to 100% cracking, breaking, etc. of film. The samples were again folded 180 ° to form a flat or flat roll so that each subsequent bend has a greater radius than the previous one. The bending is continued until an edge with a rating of 0 appears. The initial bend is Tq; the other bend is T. ^, etc. The above table shows the results for film-aluminum laminates, but similarly good results are obtained when the films are laminated to other metallic substrates, e.g. steel and galvanized steel. A process for preparing a heterogeneous, sequence emulsion polymerized copolymer comprising a first stage C 2 said first stage monomer system comprising primarily a C 2 and is a rubbery copolymer having a glass transition temperature not exceeding -20 ° C; mixture with C₂_g alkyl acrylate, and sequentially polymerize each of the subsequent monomer systems under beta processes which associate the polymer molecules formed with particles formed in the previous step or steps, wherein each subsequent step's monomer system comprises a progressively smaller amount of C monomer system is such that the final stage polymer has a glass transition temperature of at least 60 ° C, whereby the first stage polymer constitutes 10-75% by weight of the final copolymer product and the subsequent steps polymer constitutes 90-25% by weight of the final copolymer product.