DE2918265A1 - ACRYLIC GRAFT POLYMERS - Google Patents

Description

DR.-ING. WALTER ABITZ DR. DIETER F. MORF DIPL.-PHYS. M. GRITSCHNEDER

Patent attorneys

May 7th. 1979

Fc3 * an-rl-rlft / Festal Address P.O. Box 86O1O9, 8OOC Munich 8β

29T8265

Pienzenauerslraßa 23

Telephone 98 32 22

Telegrams: Chemlndue Munich

Telex: CO) 533902

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EGG. DU PONT DE NEMORS AND COMPANY Wilmington., Delaware, V.St.A.

Acrylic graft polymers

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£ 29132Π5

The invention relates to elastic acrylic graft polymers and Mixtures of such polymers with rigid, non-elastic thermoplastic methacrylate matrix resins.

Elastic acrylic graft polymers are produced using a multistage polymerization method, according to which elastic and non-elastic layers are created around an acrylic core material. You mix these up elastic polymers usually with a rigid, inelastic thermoplastic methacrylate matrix resin to impart rebound resilience to the molded or pressed parts produced from the mixture obtained. The presence the elastic acrylic graft polymer reduces the sensitivity of the molded or pressed part hard matrix resin to damage caused by impact or impact from foreign bodies.

The elastic acrylic graft polymers, however, tend to cause the resulting mixture to become cloudy or white. when molded or pressed parts made from the mixture are subjected to stresses. This appearance is referred to as "stress white coloring". For the purpose of reducing the tension white coloring, in U.S. Patent No. 3,793,402 as an elastic acrylic graft polymer to use one in which the elastic layer is both

1) surrounds a hard, inelastic core as well

2) surrounded by a hard, non-elastic shell layer

is.

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y 2 91

In the patent it is stated that when the elastic Portion of the acrylic graft polymer in the core (i.e. the first "stage") is such an arrangement that Increased tendency towards tension white coloring.

There is a continuing need for the mixtures mentioned Molded or pressed parts with improved properties produced from acrylic graft polymers and matrix resins. It has now been found that the objects obtained from such a mixture when using the inventive Acrylic graft polymers suffer a slight stress whitening even if the acrylic graft polymer has one having elastic core. With high proportions of selected acrylic graft polymers in the mixture there is also the The articles made therefrom tend to have higher Gardner impact values than those in U.S. Patent 3,793 have described products. In addition, mixtures of some of the acrylic graft polymers according to the invention show with the matrix resin the tendency to have higher folding strength values than the mixtures of the cited US Pat.

The invention creates an elastic, step-by-step process produced multistage graft polymer, which follows Polymer levels includes:

a) an elastomeric (resilient) first stage, that is, a core (which, by definition, a freezing or glass transition temperature door of about -60 to 25 ^0C, preferably -35 to -20 ⁰ C, has), which is about 1 to 25 Gev -% (preferably 3 to 20% by weight, in particular 10 to 20% by weight ) of the polymer makes up,

b) a non-elastomeric (non-elastic), relatively hard one second stage (freezing temperature above 25 ° C), the et-

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wa 5 to 65 wt% (preferably 15 to 30 wt%) des Polymers,

c) an elastomeric (elastic) third stage, which is defined as stage a) and makes up about 30 to 75% by weight (preferably 40 to 60% by weight ) of the polymer, and

d) a non-elastomeric (non-elastic), relatively hard one fourth stage, which is defined as stage b) and usually represents the last stage, which is about the 5th to 40 96% by weight (preferably 10 to 20 96% by weight) of the polymer matters.

The first polymer stage is based on a monomer mixture of 50 to 100% by weight of at least one alkyl acrylate, wherein the alkyl radical has 1 to 8 carbon atoms, 0 to 50 wt .-% of a further monoethylenically unsaturated Comonomers, 0 to 5% by weight of a polyfunctional crosslinking comonomers and 0 to 5% by weight of a graft crosslinking agent Comonomers polymerized.

The second polymer stage is carried out in the presence of the product of the first stage, starting from a monomer mixture of 70 up to 100% by weight of at least one alkyl methacrylate, where the alkyl radical has 1 to 4 carbon atoms, 0 to 30 % By weight of a further monoethylenically unsaturated comonomer, 0 to 5% by weight of a polyfunctional crosslinking agent Polymerized comonomers and 0 to 5 wt .-% of a graft-crosslinking comonomer.

The third polymer stage is carried out in the presence of the product of the first and second stage starting from a monomer mixture from 50 to 100% by weight of at least one alkyl acrylate, the alkyl radical having 1 to 8 carbon atoms, 0 to 50

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% By weight of a further monoethylenically unsaturated comonomer, 0 to 5 wt. -96 of a polyfunctional crosslinking agent Comonomers and 0 to 5% by weight of a graft-crosslinking comonomer polymerized.

The fourth polymer stage is, in the presence of the product of the first three stages, starting from a monomer mixture of 70 to 100% by weight of at least one alkyl methacrylate, the alkyl radical having 1 to 4 carbon atoms, 0 to 30% by weight of a further monoethylenically unsaturated comonomer , 0 to 5 wt -.% a polyfunctional crosslinking comonomer, and 0 to 5 wt .-% of a graft polymerized crosslinking monomers.

Make the combined proportions of polymer levels 1) and 3) at least 40% by weight, based on the polymer weight.

The final particle size of the polymer is preferably 0.15 to 0.35 μm.

The invention also provides mixtures of the elastic (resilient) graft polymers with a hard, non-elastic one thermoplastic methacrylate resin. These mixtures preferably contain 5 to 80% by weight of the elastic Acrylic graft polymers and 20 to 95% by weight of the non-elastic thermoplastic methacrylate resin, preferably a methyl methacrylate / ethyl acrylate copolymer.

The elastic acrylic graft polymers according to the invention can be produced by a multistage sequential emulsion polymerization in which each of the successive Polymer stages is polymerized in the presence of the previously generated polymer stages. Thus, each subsequent Level as a layer on top of the immediately preceding one

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Stage polymerized. Depending on the desired properties, the first polymer stage can be a seed or represent or contain a core material surrounded by more first stage. Thus, the first polymer stage or part of it is used as seed material or core to either another part of the first stage or the subsequent polymer stages polymerized in layers will. The general polymerization process is known per se. The first polymer stage or part of it, which forms the seed material includes a mechanism for determining the final grain size. When the seed material particles namely, once formed, the subsequent polymerization of the stage tends to become a polymerization of the existing particles, i.e. in general no new particles are created. The final The grain size is thus determined by the number of seed material particles the first stage regulated. The final grain size is preferably about 0.15 to 0.35 µm, especially 0.2 to 0.3 μη ». If these grain sizes are available the mixture obtained has a high ductility, i.e. molded or pressed parts produced from the mixture tend to increase Impact or impact does not result in cracks propagating from the point of impact.

The polymerization of each polymer stage is carried out in the presence of a catalyst and an emulsifier, which in usual Proportions are used, carried out. Examples of suitable emulsifiers are alkylbenzenesulfonates, alkylphenoxyp olyäthyl ensul f onate e, sodium lauryl sulphate, salts long-chain amines, salts of long-chain carboxylic and sulfonic acids and compounds which are linked to alkali metal carboxylates, Have long-chain hydrocarbon radicals bonded to sulfonates or sulfuric acid esters. Examples of suitable cata-

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The alkali metal persulfates are lysers.

The polymerization temperature may range from 0 to 125 ° C are, the range is preferably from about 60 to 90 ⁰ C.

That for the production of the elastomeric polymer stages 1) and 3) The alkyl acrylate used can be, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate or 2-ethylhexyl acrylate be. Butyl acrylate is preferred.

The alkyl methacrylate used to produce the non-elastomeric polymer stages 2) and 4) can be, for example, methyl methacrylate, Be ethyl methacrylate, propyl methacrylate or butyl methacrylate. Methyl methacrylate is preferred.

The monoethylenically unsaturated comonomer optionally used for the preparation of the polymer stages 1) to 4) can be any of the aforementioned alkyl acrylates or alkyl methacrylates or e.g. styrene, α-methyl styrene, monochlorostyrene, Butyl styrene, acrylonitrile or methacrylonitrile be. Preferably this comonomer is present in each polymer stage; in the case of the elastomeric polymer stages 1) and 3) it is preferably styrene, while in the case of the non-elastomeric polymer stages 2) and 4) it is preferably Is ethyl acrylate.

The graft-crosslinking comonomer can, for example, allyl acrylate, Allyl methacrylate, diallyl maleate, diallyl fumarate, crotyl methacrylate. Or Be crotyl acrylate. Preferably a graft crosslinking monomer s is in all polymer stages with the exception of the last stage. Furthermore, as graft crosslinking monomer allyl methacrylate is preferred.

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The polyfunctional crosslinking monomer can e.g. ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1, ^ - butylene glycol dimethacrylate, propylene glycol dimethacrylate, Divinyibenzene, trivinylbenzene, ethylene glycol diacrylate or Be 1,3-butylene glycol diacrylate. The degree of elasticity or inelasticity is determined here on the basis of the glass transition temperature.

The elastic acrylic graft polymers according to the invention are mixed with a non-elastic methacrylate resin so that the molded or pressed parts produced from the mixture are given elasticity (rebound). The proportion of the elastic graft polymer used depends on the modification of the properties which is to be made on the methacrylate resin. In general, the graft polymer is used in a proportion of about 5 to 80% by weight (preferably 30 to 60% by weight) of the mixture. It has been found that the impact strength or strength (determined according to the Gardner impact test) is higher at higher proportions of the graft polymer (for example of about 50% by weight or more) than when a known hard core graft polymer is used instead of the graft polymer according to the invention en would be used. The graft polymer and the thermoplastic resin can be mixed by any known method. It is expedient, however, to compound the two components in a roll mill, for example, for 10 to 20 minutes at 200 to 230 ⁰ C. The inelastic methacrylate resin can be a homopolymer of an alkyl methacrylate in which the alkyl radical has 1 to 4 carbon atoms, or a copolymer of two or more such alkyl methacrylates with a further monoethylenically unsaturated comonomer. Any of the aforementioned alkyl methacrylates and monoethylenically unsaturated comonomers can be used. The methacrylate resin preferably contains 75 to 100% by weight , in particular

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especially at least 90% by weight, alkyl methacrylate.

In pressed form, the mixed product is an impact-resistant and fold-resistant resin with a low tension white color (stress whitening) and can be used for the production of foils or films, plates or molded parts. If so desired you can add light stabilizers, oxidation inhibitors, fillers, colorants, lubricants or Incorporate lubricants and the like.

The physical data given in the examples below are determined as follows:

Gardner impact strengths are determined using a Model IG-1120 Tester. One in the in the examples The molded plaque, produced in the manner described, is placed on a plate through a hole of one diameter 1.63 cm (0.64 in.). A weight of 0.907 kg (2 lbs.) Is dropped on a striking head, which has a tip resting on the board with a 1.27 cm (0.5 in.) radius. The one to break the board Impact energy required (measured in J or in.-lbs.) is calculated using 0.226 J (2 in.-lbs.) impact energy increments determined and either determined by the fact that the highest value of the pass (highest impact energy value, at which the board does not break), or that the mean value is measured using the Bruceton staircase method calculated.

The tension white coloration is produced by visual inspection of in the manner described in the examples Panels after they have been subjected to the Gardner Impact Test, determined.

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The ductility is determined by the number of ductile fractures (ie all fractures resulting from the Gardner impact test , which are not straight radial or incisive (radical) cracks that extend over the impact circle with a diameter of 1.63 cm or .0.64 in.) And note the number of total fractions and plug the values into the equation below:

% Ductility = number of ductile fractures _{χ 10 (J} number of total fractures

The grain size of the acrylic graft polymers is determined by evaluating an integral comprising the Rayleigh-Gans light scattering factor for spheres, as described by F.W. Billmeyer in J. Am. Chem. Soc. 76: 4636 (1958). The results are in graphical form expressed, the particle diameter as a function of the experimentally determined values of the optical density based on the following equation:

D / A _o = 1.5 x 10 ⁷ d2 (1)

^f t

where mean:

D = optical density

= log (i00 / # permeability) (2)

A ₀ = R ² CTy (3)

R = refractive index gradient

c = particle concentration (g / cnr)

T = thickness of the optical cell (cm)

ρ = particle density (g / cnr)

d = particle diameter (μΐη)

Fm = size parameter (with constant Wavelength only a function of d).

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The refractive index gradient R can with good accuracy can be determined according to the following equation:

ο (4)

where il is the particle refractive index and η is the substrate refractive index (the coefficient 1.5 x 10 is only applied to the measurements carried out with the Hg green line at \ = 0.546 yUrii).

F _m is a known function of d, so the values of D / A are calculated and tabulated as a function of d and used to generate the log-log plot. For small particles, F _T practically has the value 1, so that log d versus log D / A _{Q represents} an essentially linear function with a slope of 1/3 for sizes up to about 0.08 pm.

With regard to the experimental part, the emulsion is diluted so that the optical transmission in the selected cell (thickness T = 1, 2.5 or 5 cm) is in the approximate range of 20 to 80 % . The transmittance at λ s 0.546 μm is measured precisely and the optical density is calculated according to equation (2). A _Q is calculated according to equation (3) using the known values of c, T and <j , while R is calculated according to equation (4). The quotient D / A related to the graph then gives the particle diameter characteristic of the emulsion. For explanation it should be assumed that a liquid with an index n ^ of 1.5 and a density 3 of 1.2 is _{emulsified in water (n Q} = 1.333) and the emulsion is diluted to 0.1% (c β 0.001) and that the permeability (relative to water) or the dilution in a 5 cm cell is measured to be 50%. Than are:

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D = log (100/50) = 0.30 (from equation 2)

R = (1.5-1.333) / i, 2 = 0.139 (from equation 4) A ₀ = (O, 139) ² (O, OO1) (5) (1.2) = 1.159 x 10 " ⁴ D / A _o = 2.59 x 10 ³ .

The graph shows that the diam

wearing.

Diameter corresponding to D / A = 2.59 x 1O ^ 0.056 μΐη BEDIE Falzbeständigkeitswerte be determined that films made from the resin blends with the indicated in Examples thickness by compression molding at 240 to 250 ⁰ C and 18144 kg (40,000 lbs) of force cut into 1.27 cm (1/2 in) wide and 10.16 to 15.24 cm (4 to 6 in) long strips and cut the strips using an MIT crease endurance tester (Tinius-Olsen Testing Machine, Co. ), while holding it under the tension generated by a weight of 0.227 kg (0.5 Ib), bending it through 180 ° at 22 ° C until the test specimen tears.

The following examples illustrate the invention.

example Polymerization

_{1000 g of deionized water (flushed overnight with N 2} ), 36 g of ethyl acrylate (ÄA), 0.2 g of ally methacrylate (ALMA) and 0.52 g of a 75 # igen are placed in a three-liter kettle equipped with a reflux condenser and nitrogen flushing device Solution of sodium dioctyl sulfosuccinate (SDOSS) (emulsifier) added. The mixture (stage 1) is 15 minutes

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vigorously stirred, the temperature being increased ^{to 80 °} C. with the aid of a water bath in which the kettle is immersed. After 15 minutes, 5 ml of 1% KpSpOg in deionized water (KPS) are added to initiate the reaction. To

Another 10 ml of KPS are added for 25 minutes. After about

A mixture (stage 2) of 108 g of methyl methacrylate (MMA), 36 g of EA, 0.4 g of ALMA and 2.08 g of SDOSS is gradually added at a rate of about 3 ml / min for 26 minutes. The total amount of level 2) is in the boiler after 85 minutes. After 110 minutes, 25 ml of KPS are added to the kettle. 5 minutes later (115 minutes) a mixture (stage 3) of 190.6 g butyl acrylate (BA), 44.7 g styrene (S), 4.7 g ALMA and 1.15 g SDOSS is gradually added at a rate of about 10 ml / min added. After 141 minutes, 20 ml of KPS are added to the kettle. After 144 minutes the total amount of level 3) is in the boiler. Stage 3) reaches a degree of conversion (determined by gas chromatography) of more than 99 % after 260 minutes. After 270 minutes, 12 ml of KPS are added. 5 minutes later (275 minutes) a mixture (stage 4) of 169.2 g MMA and 10.8 g EA is gradually added at a rate of about 4 ml / min. After 330 minutes, the entire stage 4) is in the kettle. After 360 minutes the reaction is complete and the polymer latex is cooled to room temperature. The step 1) comprises 6 wt .-% of the polymer, the stage 2) 24 wt .-% of the polymer, the stage 3) 40 wt .-% of the polymer and the step 4) 30 wt -.% Of the polymer.

insulation

The polymer latex is passed through a coarse filter cloth to separate the coagulate. 500 ml of the latex are then slowly introduced into a hot (70 to 80 ^° C.) solution of 1 % Epsom salt (1000 ml) with vigorous stirring. That

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obtained coagulated polymer is filtered, washed three times and dried overnight at 6O ⁰ C in a vacuum oven. An elastic acrylic graft polymer is obtained. The freezing temperatures (Tg) are: first stage -21 ⁰ C, second stage +64 ⁰ C, third stage -35 ⁰ C and fourth stage +94 ⁰ C. The Tg values in this example and in all other examples are determined as described in "Rohm & Haas Acrylic Glass Temperature Analyzer CM-24L / cb".

Compounding and testing

The elastic copolymers Acrylpfropfpolymere is compounded for 15 minutes at about 220 ⁰ C in a roll mill with a methyl methacrylate / ethyl acrylate (MMA / AEA). The MMA / ÄA copolymer contains about 6 % ÄA and 94 96. MMA and is mixed with 62.5% of the graft polymer. The resin mixture is mm at 240 ⁰ C and 18144 kg (40,000 lbs.) Force to 1.524 (60 mils) thick pressed board. Visual inspection shows that the panel has little haze. The Gardner Impact Test shows that the pressed mixture has a Gardner Impact (GI) value of 2.26 J (10 in-lbs.), Determined by the Bruceton method. It is found that the panel has a ductility value of 18% and that the grain size of the acrylic graft polymer is 0.155 μm. The panel shows a slight tension white color.

example

According to Example 1, an elastic four-stage acrylic graft polymer is used of the following composition using the following process steps:

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Level 1 (4 %) _ Level 2 (25 %) Level 3 (56 %) Level 4 (15 #)

19.1 g BA 4.5 g S 0.5 g ALMA 0.2 g SDOSS

Tg -35 ⁰ C

141.0 g MMA 9.0 g AE 0.6 g ALMA 1.5 g SDOSS

Tg +94 ⁰ C

266.8 g BA 62.5 g S 6.7 g ALMA 2.3 g SDOSS

Tg -35 ⁰ C

84.6 g MMA 5.4 g AE

Tg +94 ⁰ C

Time (minutes)

20th

80

98 100 136 137 270 275 299 320

Reaction stages

Addition of stage 1 Addition of 8 ml of KPS Addition of 8 ml of KPS Beginning of the addition of stage the entire stage 2 is added. Addition of 25 ml KPS. Begin the addition of stage Addition of 25 ml of KPS the entire stage 3 is added. Addition of 8 ml of KPS Beginning of the addition of stage the entire stage 4 is added. Cooling to room temperature

The graft polymer is isolated and compounded according to Example 1, except that the proportion of the graft polymer in the mixture is 40 % . The resulting panel shows little haze when visually tested and has a Gardner Impact (as determined by maximum pass value) of 16 in-lbs slight tension whiteness. The panel also has a ductility value of 100 %. The acrylic graft polymer has a particle size of about 0.27 μm.

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Eat-

example

According to Example 1, an elastic four-stage acrylic graft polymer is used of the following composition using the following process steps:

Level 1 (4 %) Level 2 (25 %) Level 3 (56 %)

1Q-? σ ΒΔ 14O, 4 g MMA

g BA 4.2 g S 0.4 g ALMA 0.1 g EDMA * 0.2 g SDOSS

Tg -35 ⁰ C

9.0 g LA 0.6 g ALMA 0.6 g EDMA 1.6 g SDOSS

Tg +94 ⁰ C 268.7 g BA 59.1 g S 6.7 g ALMA 1.7 g EDMA 2.6 g SDOSS

Tg -35 ⁰ C

Level 4 (15 %)

84.6 g MMA 5.4 g IA 0.5 g EDMA

Tg +94 ⁰ C

Time (minutes)

00

80 116 126 131 183 188 295 300 327 340 Reaction stages

Addition of stage 1 Addition of 12 ml of KPS Addition of 8 ml of KPS Beginning of the addition of stage the entire stage 2 is added. Addition of 25 ml KPS. Begin the addition of stage Addition of 25 ml of KPS the entire stage 3 is added. Addition of 12 ml of KPS Beginning of the addition of stage the entire stage 4 is added. Cooling to room temperature

* EDMA = ethylene glycol dimethacrylate (crosslinking agent)

The graft polymer is isolated and compounded according to Example 2. The panel obtained shows little haze.

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The Gardner Impact Test gives a Maximum Pass Impact Strength (GI) of 3 »62 J (16 in-lbs.). The panel shows a slight white coloration and has a ductility value of 95 %. The acrylic graft polymer produced according to this example has a grain size of 0.272 μm.

example

According to Example 1, an elastic four-stage acrylic graft polymer is used with the following composition using the following process steps:

Level 1 (5th %) Level 2 (25 %) Level 3 (55 %) Level 4 (15 %)

24.1 g BA 140.4 g MMA 261.5 g BA 84.6 g MMA 5.7 g S 9.1 g AE 61.3 g S 5.4 g AE 0.6 g ALMA 0.7 g ALMA 6.1 g ALMA 0.23 g SDOSS 1.52 g SDOSS 2.52 g SDOSS

Tg -35 ⁰ C Tg +94 ⁰ C Tg -35 ⁰ C Tg +94 ⁰ C

Time (minutes) reaction levels

00 Addition of level 1

10 Add 12 ml of KPS

65 Add 8 ml of KPS

70 Beginning of addition of stage

100 the entire stage 2 is added

110 Addition of 25 ml KPS

115 Beginning of addition of stage

162 the entire stage 3 is added

165 Addition of 25 ml KPS

275 Addition of 25 ml KPS

280 Beginning of the addition of stage

307 the entire stage 4 is added

327 Cooling down to room temperature

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The graft polymer is isolated and compounded according to Example 2. The panel obtained shows little haze. The Gardner Impact Test gives a maximum pass impact strength of 4.52 J (20 in-lbs.). The panel shows a slight tension white coloring. The ductility value is 100 %. The acrylic graft polymer produced according to this example has a particle size of 0.272 μm.

example

According to Example 1, an elastic four-stage acrylic graft polymer is used of the following composition prepared using the following process steps;

Level 1 (4th %) Level 2 (20 %) Level 3 (56 ^) Level 4 (20 %)

19.1 g BA 112.3 g MMA 266.8 g BA 113.0 g MMA

4.5 g S 7.2 g AE 62.5 g S 7.2 g XA 0.2 g EDMA 0.5 g ALMA 6.7 g ALMA 0.2 g SDOSS 1.2 g SDOSS 2.5 g SDOSS

Tg -35 ⁰ C Tg +94 ⁰ C Tg -35 ⁰ C Tg +94 ⁰ C Time (minutes) Reaction levels

00 Addition of level 1

15 Addition of 10 ml of KPS

50 Beginning of the addition of stage 2

74 the entire stage 2 is added

95 Addition of 25 ml KPS

100 Beginning of the addition of stage 3

154 Addition of 25 ml KPS

159 the entire stage 3 is added

287 Addition of 12 ml KPS

292 Beginning of the addition of stage 4

331 the entire stage 4 is added

356 Cooling down to room temperature

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The graft polymer is isolated and compounded according to Example 2. The panel obtained shows little haze. The Gardner Impact Test gives a maximum pass impact value of 1.36 J (6 in-lbs). The panel shows a slight tension white coloring. The ductility value is 100 %. The acrylic graft polymer produced according to this example has a particle size of 0.245 μm.

example

According to Example 1, an elastic four-stage acrylic graft polymer is used with the following composition using the following process steps:

Level 1 (6 %) Level 2 (24 %) Level 3 (40 %) Level 4 (30 %)

36.0 g AE 144 ⁰ C Tg , 0 G MMA 190.6 G BA 169.2 grams of MMA 0.3 g SDOSS 0 (Minutes) , 4 G ALMA 44.7 G S. 10.8 g ÄA 2 »Ο G SDOSS 4.7 F, ALMA 0.40 g n-Bu- 1.0 G MAA tyl mercaptan 1.1! > ί I SDOSS (n-BM) Tg -21 + 1Of Tg -35 ' ⁰ C Tg +94 ⁰ C Time Reaction stages

00 Addition of level 1

15 Addition of 10 ml of KPS

72 Beginning of the addition of stage 2

94 the entire stage 2 is added

114 Addition of 25 ml KPS

119 Beginning of the addition of stage 3

144 Addition of 20 ml KPS

147 the entire stage 3 is added

212 Addition of 12 ml KPS

217 Beginning of the addition of stage 4

271 the entire stage 4 is added

291 cooling down to room temperature

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The graft polymer is isolated and compounded according to Example 1. The panel obtained shows little haze. The Gardner impact test gives an impact strength value of 4.52 J (20 in-lbs.), Determined by the Bruceton method. The panel shows a slight tension white coloring. The ductility value is 78 %. The acrylic graft polymer produced according to this example has a particle size of 0.174 μm.

example

According to Example 1, an elastic four-stage acrylic graft polymer is used with the following composition using the following process steps:

Level 1 (6 %) Level 2 (24 %) Level 3 (40 %) Level 4 (30 %)

7.2 g MMA 144, OgMMA 190.6. g BA 169.2 g MMA

28.8 g ÄA 0.4 g ALMA 44.7 g S 10.8 g ÄA

0.5 g SDOSS 2.0 g SDOSS 4.7 g ALMA 0.45 g n-BM

1.0 g MAA 1.15 g SDOSS

Tg -4 ⁰ C Tg +105 ⁰ C Tg -35 ° C Tg +94 ⁰ C

Time (minutes) reaction levels

00 Addition of level 1

15 Addition of 10 ml of KPS

60 Beginning of the addition of stage 2

84 the entire stage 2 is added

104 Addition of 25 ml KPS

109 Beginning of the addition of stage 3

134 Addition of 20 ml KPS

137 the entire stage 3 is added

253 Addition of 12 ml KPS

258 Beginning of the addition of stage 4

309 the entire stage 4 is added

329 cooling to room temperature

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The graft polymer is isolated and compounded according to Example 1. The panel obtained shows little haze. The Gardner impact test gives an impact strength value of 3.16 J (14 in-lbs.), Determined by the Bruceton method. The panel shows a slight tension white coloring. The ductility value is 100%. The acrylic graft polymer produced according to this example has a particle size of 0.203 μm.

Example 8

A) 20,000 g of deionized water, 381 g of BA, 87 g of S, 9 g of ALMA and 3.6 g of SDOSS are placed in a 37.85 l (10 gallon) reactor made of corrosion-resistant steel. The mixture (stage 1) is vigorously agitated and the kettle is evacuated to about -635 mm (-25 in) Hg for 30 seconds and then pressurized with nitrogen to 0.483 bar (7 psi). The nitrogen is then vented to a final pressure of 0.138 bar (2 psi). The temperature is increased to 80 ^° C. during this time. 13 minutes after starting exercise, its intensity is reduced to about half. After 15 minutes, 60 ml of KPS (2 % KpS ₂ Og in deionized water) are added. This process is repeated after 48 minutes. After 109 minutes, a mixture (stage 2) of 2820 g of MMA, 180 g of JiA _1, 12 g of ALMA and 30 g of SDOSS is gradually pumped into the reactor. A further 60 ml of KPS are added after 110 minutes. After 126 minutes, the entire stage 2 is in the reactor. After 150 minutes a further 250 ml of KPS are added. Then step 3 is gradually pumped in, which consists of 4863 g BA, 1110 g S, 110 g ALMA and 47 g SDOSS. After 186 minutes, 250 ml of KPS are added. After 190 minutes, the entire stage 3 is in the reactor. After 327 minutes, 80 ml of KPS are added. After 330 minutes it will

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stage 4, which consists of 2256 g of MMA and 144 g of EA, is gradually pumped into the reactor.

The entire stage 4 is in the reactor after 354 minutes. The reaction is allowed to proceed for a further 16 minutes then cools the batch to room temperature.

insulation

The polymer latex is diluted with demineralized water in a ratio of 1: 1. Then the latex is gradually pumped at a rate of 1.9 l / min (0.5 gallon / min) under stirring into a 208.2 l. (55 gallons) barrel drum which a hot (50 to 6O ⁰ C) Contains a solution of 64.3 liters (17 gallons) of demineralized water and 625 g of Epsom salt. When the coagulation is complete, the mother liquor is drained off and the coagulated polymer ^{is washed three times with hot (55 °} C.) deionized water. The polymer is then dried in the vacuum oven overnight. An elastic acrylic graft polymer is obtained (the grain size is not determined).

Compounding and testing

A mixture of _9} O7 kg (. 20 lbs) of the graft polymer and 13.61 kg Lucite®47F (methyl methacrylate / ethyl acrylate copolymer; 94: 6) (30 lbs.) Is prepared in a drum mixer. The mixture is pph in a twin screw extruder and extruded at about 150 a melting temperature of about 270 ⁰ C. The resulting melt-compounded, pelletized product is then extruded in a single screw extruder equipped with a sheet mold. The resulting film has a thickness of 1.73 to 1.905 mm (68 to 75 mils), very low haze, an impact value of 6.1 J (27 in-lbs.) (Bruceton method) and a moderate

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rings tension white coloring. The toughness of the film made from this composition is at least 27 times that of a film made from Lucite®47F alone. The ductility is about 100 %.

B) 20,000 g of deionized (demineralized) water, 381 g of BA, 87 g of S, 9 g of ALMA and 3.6 g of SDOSS are placed in a 37.85 liter (10 gallon) reactor made of corrosion-resistant steel. The mixture (level 1) is moved vigorously. (250 rpm) and the kettle evacuated to about -635 μ (-25 in.) Hg for 30 seconds and then pressurized with nitrogen to 0.483 bar (7 psi). The nitrogen is then vented to a final pressure of 0.138 bar (2 psi). During this time the temperature is increased to 78 ° C. 12 minutes after starting exercise, its intensity is reduced by about half. After 15 minutes, 120 ml of KPS (2 % K ₂ S ₂ O ₃ in deionized water) are added. The temperature is raised to 8O ⁰ C after 16 minutes. After 40 minutes, a further 80 ml of KPS are added. After 45 minutes a mixture (stage 2) of 2808 g MMA, 180 g ÄA, 12 g ALMA and 30 g SDOSS is gradually pumped into the reactor. After 72 minutes, the entire stage 2 is in the reactor. After 95 minutes a further 250 ml of KPS are added. After 100 minutes, stage 3, which consists of 5342 g BA, 1243 g S, 134 g ALMA and 54 g SDOSS, is gradually pumped into the reactor. After 139 minutes, 250 ml of KPS are added. After 144 minutes, the entire stage 3 is in the reactor. After 275 minutes, 120 ml of KPS are added. After 280 minutes, stage 4, which consists of 1808 g of MMA and 117 g of EA, is gradually pumped into the reactor.

The entire stage 4 is in the reactor after 307 minutes. The reaction is then allowed to take place for a further 23 minutes.

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AD 4929 A «A

run, after which the batch is cooled to room temperature.

The stage 1 is 4% of the total polymer and has a glass transition temperature (Tg) of -35 ⁰ C. The percentages and Tg values for the other levels are: Level 2 25% / + 96 ° C; Level 3 55? V-35 ° C; and level 4 15% / + 96 ° C.

Isolation and testing

The rubber is isolated according to Example 8. The final latex grain size is 0.275 μm. The product is then compounded and compression molded according to Example 1, except that the proportion of the graft polymer in the mixture is 40 % and the copolymer contains 6 % EA and 94 % MMA.

The following physical data are determined:

Gardner Impact Tensile Strength, Elongation, %

Viscosity *, J bar (psi)

(in-lbs.)

5.65 (25) 357.2 (5180) 32

^ determined by the Bruceton method

The tension white color is slight and the ductility is around 100 96.

example

According to the general method of Example 1, the following batches are successively placed in a 3 liter resin kettle

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030030/0536

^ SPECTED

AD 4929 A

ben and each for the production of an inventive
Four-stage resin and a three-stage resin not according to the invention implemented.

Four-stage resin according to the invention

Approach for level 1 (elastomer) Approach for level 2 (non-

elastomer)

10.9 g styrene (S) 48.0 g butyl acrylate (BA) 1.2 g allyl methacrylate (ALMA) 0.60 g aerosol OT

(75 % solution) (A-OT) 113.5 g MMA

6.0 g ethyl acrylate (JiA) 0.5 g ALMA 1.20 g A-OT

Approach for level 3 (elastomer) Approach for level 4 (non-

elastomer)

59.9 g S 263.6 g BA 6.5 g ALMA 3.30 g A-OT 85.5 g MMA 4.5 g ÄA

Time reaction temperature ^{, 0 C}

Remarks

79

80 80 80

80 81 80

80 80 Addition of 26 ml of monomer batch from stage t

Add 12 ml KPS Add 12 ml KPS Start adding the remainder of the stage 1 at about 4 ml / min the entire stage 1 is added Add 12 ml of KPS start adding stage 2 at approx 5 ml / min

the entire stage 2 is added. Addition of 25 ml of KPS

- 24 03G030 / 053B

AD 4929 A

Time reaction temperature ^{, 0 C}

Remarks

80

80 80 81 80

81 80 Beginning of the addition of stage 3 approx. 8 ml / min

Addition of 25 ml of KPS the entire stage 3 is added. Addition of 12 ml of KPS Start adding stage 4 at about 3 ml / min

the entire stage 4 is added

The batch is cooled to room temperature

Three stages-Harζ

Approach for level 1 Approach for level (non-elastomer) (elastomer)

170.3 g MMA 9.0 g AE 0.7 g ALMA 1.80 g A-OT

59.9 g S 263.6 g BA 6.5 g ALMA 3.30 g A-OT approach for step (non-elastomeric)

85.5 g MMA 4.5 g AE

Time reaction tem- Remarks ρeratü r, ° C

0 79 15th 79 30th 81 60 80 75 80 80 80 120 80 127 80

Add 52 ml of monomer for step 1

Addition of 15 ml of KPS

Start adding the remainder of the stage at about 5 ml / min

the entire stage 1 is added. Addition of 25 ml of KPS

Start adding stage 2 at about 8 ml / min

Addition of 25 ml of KPS

the entire stage 2 is added

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AD 4929 A 2918263

Time reaction temperature, ⁰ C

227 81 addition of 12 ml KPS

232 80 Start of the addition of stage 3 at about 3 ml / min

264 81 the entire stage 3 is added

289 80 Cooling of the batch to room temperature

The resins are in each case isolated by evaporating the latex in vacuo at 70 to 9O ⁰ C to dryness. The isolated resins are then compounded according to Example 1 with an MMA / ÄA (95/5) copolymer. The products are then to about 1.016 mm (about 40 mils) thick compression molded plaques for tensile testing and 0.305 mm (12 mils) thick films for Falzbeständigkeitstest at 240 ⁰ C and 18,144 kg (40,000 lbs.) Force. 0.178 mm (7 mils) thick films are produced by pressing at 250 ⁰ C.

Table I shows the prosentity and Tg of each Polymer level and the grain size of the resin.

% Day TABELLI % Day 15th
15th 4th Day final
Grain size, 0.280
0.282 1 10
- ** -35 5 I. 55
55 -35
-35 +96
+96 (in the Polymer levels *
2 3 % Day 20 +96
30 +96

Four stage resin

Three-step resin

♦ The Tg values (in ⁰ C) are calculated ** 4 % germ material *** 8 % germ material

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030030/0536

It can be seen that the last two stages of each resin are identical in composition and amount present and that the only difference is that the core portion of the three-stage resin is non-elastomeric and makes up 30% of the total polymer, while the core of the four-stage resin is en resin represents 10 % elastomer with 20 % a non-elastomeric second stage.

The crease resistance test gives that shown in Table II Values (in this table are the acrylic graft polymer proportions in the MMA / ÄA mixture, the film thicknesses and the numbers of samples tested).

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3 0 0 3 0/0536

σ I. co IVO ο 00 O f co O CS crt co bi

composition

Three-step resin

Four stage resin

Three-step resin

Four stage resin

Three-step resin

Four stage resin

TABLE II Fold resistance test

Share of
Acrylic graft
polymers in
MMA / ÄA resin ,% Film thickness, μπι
(mils) number of
rehearse Bends up
to break * 32 292.1 t 10.16
(11.5 ± 0.4) 9 2.8 ± 1.1 32 281.9-5.08
(11.1 + 0.2) 10 3.1 ± 1.3 50 325.1 ± 7.62
(12.8 + 0.3) 12th 9.0 i 3.1 ** 50 335.3 ± 10.16
(13.2 ± 0.4) 9 12.6 ί 4.1 ** 50 188.0 ± 10.16
(7.4 + 0.4) 16 31.0 ± 8.4 *** 50 190.5 J 12.7
(7.5 ± 0.5) 16 42.4 ± 12.4 ***

VO VO

Oo

* Number of bends through 180 ° until breakage

** On the basis of statistical analyzes - which are carried out according to the variance stabilization transformation method (see Advanced Theory of Statistics, MGKendall and A.Stuart. Vol. 3, 2nd edition, page 89), the improvement is 40 % (12, 6 versus 9.0) can be implemented with a degree of reliability of more than 95 % .

*** On the basis of the same statistical analysis as in footnote ** the improvement of 37 % (42.4 versus 31.0) can be achieved with a degree of reliability of more than 95 % .

OO K) cn

The percentage improvements show that the inventive Four stage resin at any acrylic polymer content and especially has a higher crease resistance for each tested film thickness at the higher contents.

Tensile strength, Gardner impact and ductility tests reveal no significant differences between the three-stage resin and the four-stage resin.

Example 10

Following the general method of Example 1, a four stage resin is made with 20 % first stage elastomeric and compared to a three stage resin. In the manufacture of the two resins, the following batches for the formation of the polymer stages are prepared in the proportions shown;

Four-stage resin according to the invention

Level 1 (20 %) Level 2 (10 %) Level 3 (55 %) Level 4 (15 %)

96.0 g BA 56.8 g MMA 263.6 g BA 85.5 g MMA

21.8 gS 3.0 g AE 59.9 gS 4.5 g AE

2.4 g ALMA 0.25 g ALMA 6.5 g ALMA

1.20 g SDOSS 0.60 g SDOSS 3.30 g SDOSS

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AD 4929 A

Time (minutes) reaction levels

00 15 35 40 70

75 158 163 178 193 193 240 244 344 349 379 399

Add 20 ml level 1

Add 12 ml of KPS

Add 12 ml of KPS

Beginning of adding the remainder of stage 1

the entire stage 1 is added

Add 12 ml of KPS

Add 12 ml of KPS

Beginning of the addition of stage 2

the entire stage 2 is added

Addition of 25 ml of KPS

Beginning of the addition of stage 3

Addition of 25 ml of KPS

the entire stage 3 is added

Add 12 ml of KPS

Beginning of the addition of stage 4

the entire stage 4 is added

Cooling down to room temperature

The grain size is 0.340 μm.

Three-step resin

Level 1 (30 %)

170.3 g MMA 9.0 g AE 0.7 g ALMA 1.80 g SDOSS

Level 2 (55 %) 263.6 g BA 59.9 g S 6.5 g ALMA 3.30 g SDOSS

Stage 3 (15 %) 85.5 g MMA

4.5 g AE 4.5 g AE

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Time (minutes) reaction levels

00 Addition of 38 ml stage

15 Addition of 15 ml of KPS

30 Beginning of adding the remainder of stage 1

62 the entire stage 1 is added

82 Addition of 25 ml of P [PS

87 Beginning of addition of stage

125 Addition of 25 ml KPS

149 the entire stage 2 is added

250 addition of 12 ml KPS

255 Beginning of addition of stage

286 the entire stage 3 is added

311 cooling to room temperature

The grain size is 0.320 μm.

The comparison below shows the percentages of the polymer levels, the resin grain size and the Tg values of the Polymer levels:

Steps final grain size,

Tg * % Tg % Tg % Tg

30 +96 55 -35 15 +96 0.320 (5 % seed material)

Four-stage 20 -35 10 +96 55 -35 15 +96 0.340 resin (3 % seed material)

^ calculated Tg values (° C)

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030030/053 6

AD 4929 A

The resins are isolated according to Example 9 and compounded according to Example 1 with 95/5 MMA / ÄA with acrylic graft polymer contents of 32 % and 50 % . The compounded resins are tested for Gardner impact strength, with the following values being achieved:

Gardner impact strength

Three-stage resin mixture. Four-stage resin mix 30/55/15
50 % polymer content 20/10/55/15
50 % polymer content 30.1
31.5
34.6 37.0
45.3
39.2

32.1 ± 2.3

32 % Polymer content

14.7 15.6 15.6

15.3 ± 0.5

40.5 ± 4.3

32 % Polymer content

15.5 to 2.1

It can be seen that with an acrylic graft polymer content of
32%, no significant difference can be found with regard to the Gardner impact strength, while the four-stage polymer according to the invention gives a 26% improvement at a proportion of 50%. No significant difference was observed with regard to the stress whiteness or ductility. The tensile strengths are not measured.

End of description

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030030/0536

Claims (10)

PATENT CLAIMS j Elastic, sequentially produced multi-stage acrylic polymer, marked by a) an elastomeric first stage, which represents about 1 to 20 wt .-% of the polymer and a freezing temperature (glass transition temperature) of about -60 to 25 ⁰ C and which consists of a monomer mixture of 50 to 100 wt. % At least one Alkyl acrylate, where the alkyl moiety has 1 to 8 carbon atoms, 0 to 50 wt -.% of a further copolymerizable monoethylenically unsaturated monomer, 0 to 5 wt .-% of a copolymerizable polyfunctional crosslinking monomer, and 0 to 5 wt .-% of a copolymerizable graftlinking monomer is polymerized, represents% of the polymer and having a glass transition temperature of more than 25 ⁰ C and in the presence of the product of the first stage from a monomer mixture of 70 to 100 - b) a non-elastomeric, relatively hard second stage comprising about 15 to 65 wt. Wt% 030030/0536 AD 4929 A 29182R5 having at least one alkyl methacrylate, wherein the alkyl radical from 1 to 4 carbon atoms, 0 to 30 wt -.% of a further copolymerizable monoethylenically unsaturated monomer, 0 to 5 wt -.% of a copolymerizable polyfunctional crosslinking monomer \ mcl 0 to 5 wt -.% a copolymerizable graft-crosslinking monomer is polymerized, c) an elastomeric third stage, which is about 30 to 75 parts by weight of the polymer 96 and having a glass transition temperature of about -60 to 25 ^0C and in the presence of the product of the first and the second stage from a monomer mixture of 50 to 100 wt -.% of at least one alkyl acrylate wherein the alkyl group has 1 to 8 carbon atoms, from 0 to 50 parts by weight 96 of a further copolymerizable monoethylenically unsaturated monomer, 0 to 5 wt -.% of a copolymerizable polyfunctional crosslinking monomer, and 0 to 5 wt. - % of a copolymerizable graft crosslinking monomer is polymerized, and d) a non-elastomeric, relatively hard fourth stage, which represents about 5 to 40 wt .-% of the polymer and has a glass transition ^{temperature of more than 25 0} C and which in the presence of the product of the first, second and third stage from a monomer mixture from 70 to 100 wt .-% of at least one alkyl methacrylate, wherein the alkyl group has 1 to 4 carbon atoms, 0 to 30 wt -.% of a further copolymerizable monoethylenically unsaturated monomer, 0 to 5 wt .- 6 of a copolymerizable polyfunctional crosslinking monomer, and 0? until 030030/0536 AD 4929 A J 23182B5 5% by weight of a copolymerizable graft-crosslinking agent Monomers is polymerized, wherein the first and third stages taken together is at least 40 wt -.% of the polymer represent. 2. Polymer according to spoke 1, characterized in that the elastomeric first stage about 3 to 10 wt .-% of the polymer, the non-elastomeric second stage about 20 to 30 wt .-% of the polymer, the elastomeric third stage about 40 to 60% by weight of the polymer and the non-elastomeric fourth stage represents about 10 to 20% by weight of the polymer. 3. A polymer according to claim 1 or 2, characterized in that the glass transition temperature of the elastomeric first stage, and the elastomeric third stage in each case amount to about -35 to -20 ⁰ C. 4. Polymer according to claim 1 to 3 »characterized in that in the elastomeric first stage and in the elastomeric third stage alkyl acrylate present is in each case butyl acrylate. 5. Polymer according to claim 1 to 4, characterized in that the in the non-elastomeric second stage and in the alkyl methacrylate present in the non-elastomeric fourth stage is methyl methacrylate. 6. Polymer according to claim 1 to 4, characterized in that the monomer mixture of the non-elastomeric second Stage methyl methacrylate, ethyl acrylate and allyl methacrylate and the non-elastomeric fourth stage monomer mixture contain methyl methacrylate and ethyl acrylate. 030030/0536 AD 4929 A 7. Polymer according to claim 1 to 6, characterized in that the elastomeric first stage 3 to 20 wt .-% of the polymer represents. 8. Polymer according to claim 7, characterized in that the elastomeric first stage 10 to 20 wt .-% of the polymer represents. 9. Polymer according to claim 1 to 8, characterized in that the elastomeric first stage is a seed material (seed) contains. 10. Polymer according to claim 1 to 9, containing 20 to 95 wt .-%, based on the totality of the polymer and the methacrylate resin, an inelastic thermoplastic Methacrylate resin, preferably a methyl methacrylate / ethyl acrylate copolymer. 0 3:. · :: ·? η / 0 5 3
ORIGINAL! W