DE1939696A1 - Process for the production of finely divided, expandable polymers - Google Patents

Description

PATENT LAWYERS,. I 9 39696

dr. W. Schalk dipl.-ing. P. Wirth dipl.-ing. G. Dannenberc

"DR.V. SCHMIED-KÖWARZIK · DR. P. WEINHOLD · DR. D. GUDEL POSTSCHECK ACCOUNT 15630 FRANKFURT (M) · THANKS.! DRESDNER BANK ACCOUNT 152 566 FRAN KFURT (M)

WIRE ADDRESSi WIRPATENTS

Case 64; 1OBG '

KOPPSiiS COMPANY, Inc.

456, Seventh Avenue Pittsburgh, Pa., USA

6 FRANKFURT AM MAIN CR. ESCHENHEIMER STR. 39 TELEPHONE CO6II) 281134

Wd / Eh ^2e7OU

Process for the production of divided, expandable polymers

The present invention relates generally to expandable Polymers, and it relates in particular to finely divided, expandable Styrene-Acrylnit-ril-EisciiiiOlynierisate as well as a method to their manufacture.

009814/1890

Expandable polystyrene beads, such as those under the designation
"DYLITE" known hand oil brittle products are manufactured by suspens-io-napolyir; ürioution. A description of the process for making polystyrene beads by suspension polymerization is found in U.S. Patent 2,656,534. How these spheres are made expandable is described in US Pat. No. 2,936,92. Since foams made from styrene homopolymers are attacked by organic solvents such as gasoline, the article "Novel Foams from
Styrene-Acrylonitriie Gopolymeris "in Journal öf Cellular Plastics,
January 1965t Volume 1, No. 1, copolymers of styrene and acrylonitrile described, which do not have these disadvantages.

The polymer particles obtained by known suspension systems, such as, for example, the systems of US Pat. No. 2,656,334, have in the ·
generally a size of about 300 to 2000 cm (with a sieve mesh size of 0.297 now on a mesh size of 2.0 mm), t / above ^for most of the particles larger than 5OO7U. (on a mesh size of 0.5 mm). Particles of this size are suitable for the "production of aiil- - rich objects, such as blocks, plates, packaging, insulating material, ceiling tiles and beakers, small spheres are sieved out and discarded, because" the small spheres do not bind any separating agent "and lead to foamed materials of poor quality if they are left in the product (expandable polymer) -

^, 0 ^ 814/1890

Attempts have already been made to mix the beads of an expandable polymer with a latex, but even the smallest, so far The beads produced are too large after expansion to be a to be delivered with a smooth coating, e.g. when coated with a paint Latex base can be mixed. Such large particles do not ground homogeneously dispersed in the paint, and the coating produced with it has a very uneven surface and shows elevations at the points where the individual spheres lie. Zv ^ isch the paint layer the bead has no insulating properties.

The latex emulsions known to date have a particle size of 0.1 to 1/1. It is of course possible to produce finely divided styrene polymer in the form of a latex emulsion. Attempts to incorporate an expanding agent into the latex to make the SfyxoItellchen expandable, either before or after formation of the latex, were unsuccessful because essentially no permanent binding of the blowing agent in the particles could be achieved. Even more serious problems occurred when “ the polymer particles were separated from the latex and. tried to provide the dried particles with a blowing agent, since the blowing agent escaped very quickly from the very small latex particles, which have an extremely large surface area compared to the volume of the material. In order to achieve any expansion of the particles at all, the particles must be expanded immediately after the impregnation stage - and before the blowing agent can escape from the particles.

0098 U / 18 9Ch:

- 4 - ■■■■. ■. ■ '■ -. -

The aim of the present invention is to create small particles of expandable thermoplastic polymer which retain the expanding or blowing agent for a long time. According to the invention, vinylaryl-acrylonitrile copolymer particles are created which predominantly have a particle size of about 38 to 296 ij. and in which a volatile blowing agent is dispersed. The small particles hold back the blowing agent for a long time, even if they are stored in the form of a dry ψ solid. The particles are so small that they can be mixed homogeneously with the known latices.

The inventive. expandable copolymers are produced, by making an aqueous suspension of acrylonitrile, a Vinyl aryl monomers, a free radical generating catalyst, a volatile blowing agent and a suspending agent which has an equimolar Copolymer of methyl vinyl ether and maleic anhydride comprises, and this suspension is heated, unfine polymerization of the . To effect aryl vinyl monomers with the acrylonitrile. . ·

The polymerisation product is a suspension of fine vinylaryl / aerylnitrile copolymer particles, which is predominantly a size of about 38 to 296 //. The particles can be obtained by filtering the aqueous phase are separated. However, since the particles remain in suspension and do not have to be separated from the suspension, the suspension can be used immediately by e.g. for coating purposes with a latex emulsion or for the production of Packaging material mixed with paper pulp.

009814/1890

. The accompanying drawings serve to explain the present

Invention, namely shows:

Figure 1 is a graph showing the ratio of acrylonitrile in. the monomer mixture to parts of water throughout Reaction mass of water and monomer mixture that is required is to produce a copolymer with an acrylonitrile content of make about 28.5 "$, and.

2 shows the graphic representation of a series of samples according to " Example 11 showing the retention of isopentane in the product as a function of the acrylonitrile in the monomer mixture a ratio of water to monomer mixture of 75 * 25 and using the sodium hydroxide treatment.

As already stated, the novel process provides finely divided, expandierbäre Vinylar ^ l ^ acrylonitrile Mischpolymerisai ^ eilohen whose size mainly between about 38 and 296 u, is located. The expandable particles according to the invention contain about 26.5 ^ acrylonitrile and surprisingly can retain the expanding agent for a longer period of time. You will be using a special

Suspension polymerisation systems produced.

. Although many suspending agents are known for the suspension polymerization of styrene, only the non-neutralized, equimolar copolymers of methyl vinyl ether and maleic anhydride have proven suitable for the production of the polymer particles according to the invention. Attempts to change for Styrofoam! Polymerizations'

- 6 - ■ ■. ■; ■ ■ - ■

using known suspending agents resulted in either of the usual ones Spheres (e.g. hydroxyethyl cellulose and polyvinyl alcohol) or an agglomerated mass (e.g. polyacrylamide, sodium polyacrylate, Polyethylene oxide, styrene-maleic anhydride mixed polymer, polyacrylic acid and alginic acid). ·

'l - ■■ - ■■ - - ■■ ■ "■.

Particularly suitable suspending agents for the process according to the invention are methyl vinyl ether-maleic anhydride copolymers with medium or high molecular weight (a solution of 1.0g copolymer in 100 ecm methyl ethyl ketone should have a specific viscosity from 1.0 to 3.5 at 25). These copolymers are commercially available in the form of very fine white powders (Gantrez AN-139 » An-169 etc., General Aniline and Film Corp.).

Furthermore, it has been found that the pulverulent suspending agent has to be slurried in order to produce the desired product, and either (a) in the aqueous phase before adding the monomers or (b) in the monomer mixture before adding the monomers to water. Will the suspending agent first dissolved in a small amount of water (the copolymers are easily soluble in water at 90 °) and then to the mono feed is added to water instead of a fine one Suspension is a dry, agglomerated mass of the copolymer obtain· .

Di · amount of suspending agent which provides a fine Suepension Polymerisatteilohen and no agglomerated Polyaerisatmasse or conventional ball up "is about 0.20 bia 6 percent, - ^ _v based on weight DAtF

-λ-ii:

of the monomers. ., Less than about 0.20 wt -fo suspending agent used, occurs either no suspension a, "or are formed jgrp-s.se beads; "with amounts of more than about 6 wt .- ^ a usual suspension of spheres larger than about 0.3 mm is obtained.

Contains the monomer mixture introduced into the reaction device at least about 50% by weight of a vinyl aryl mononate or mixture of aryl vinyl monomers; the remainder of the charge consists of acrylonitrile. Examples of suitable vinyl aryl monomers are styrene, divinylbenzene, Isopropylstyrene, © C-methylstyrene, nucleus-substituted dimethylstyrene, Ethyl styrene, chlorostyrene, vinyl naphthalene, etc. and mixtures of these compounds.

The amount of acrylonitrile used depends, as explained in more detail below, on other reaction conditions. In all cases, however, the charge contains at least enough acrylonitrile that the copolymer product has at least 28.5 wt .- ^ acrylonitrile.

The ratio of monomers to water in the feed is not critical. However, it was surprisingly found that the suspension viscosity decreases with an increasing ratio of monomer to water. While with a monomer. Water ratio of 25 «75 percent - $> the product is a thixotropic © mass, which are diluted with water to a 18 to 20 wt .- ^ solids dispersion must

■ - β -

00S8U / 189Q

- ■■ β'-, ■■■,. ■■: -

so that it can be poured and filtered, a monomer-water ratio of about 50:70 to 45-55% by weight leads to easily pourable fine particles Suspensions. As can best be seen from the graph in the figure, the minimum amount of acrylonitrile also varies the feed of monomer mixture, which provides a copolymer with an acrylonitrile content of at least 28.5 wt .- ^, with the Ratio of monomer mixture to lasser in the polymerization. So should e.g., as from the first, referred to as "NaOH treatment" Line can be seen at a monomer-water ratio of 50:70 the acrylonitrile monomer content of the monomer mixture is at least about 54 »5 parts by weight per 100 parts by weight of the monomer mixture, if Interpolymer particles are to be produced which contain at least 28.5% by weight of acrylonitrile.

'"■' - ■ - ■■, ./".'■. "so ■ -... ■■." ■ "'■ ■' - '. - ■" - - ■ "Generally / finely divided, expandable styrene-acrylonitrile polymer particles, the size of which is predominantly between about 38 and 296 / JL, is, prepared by suspension polymerization, v / obei non-neutralized, equimolar copolymers of methyl vinyl ether and maleic anhydride are used as suspending agents. Since the particles obtained are very small, they can be mixed with various binders and thickeners and produce expandable coatings. Despite their small size however, they can hold back the volatile aliphatic blowing agents for a long time and therefore remain expandable for a long time.

- ■■■ ■ '"■': ■ ■ -.- '. ■"■'"'. ■■ ■'■" ⁹ - 0098H / 1890

The graphic representation of Fig. 1 shows two lines with '"NaOH treatment" and "NaOH treatment" respectively. are marked with "on ^ne NaOH treatment". In order to produce a copolymer which is practically free of radical acrylonitrile and does not show any discoloration, according to a preferred embodiment, during the above-described polymerisation

. . ■ ■ ■■■ - "■ - ■ χ.

tion added a base to the polymerization mixture. This base is added to the polymerization mixture at about the point in time at which the beads can be perceived ("bead identity point"). In a stirred suspension, the individual droplets of the monomer make-up become stickier as the polymerization proceeds and tend to combine to form larger droplets. After a certain degree of polymerization (conversion of about 75 to 85 fo, determined by periodically taking samples from the reaction mixture) the drops no longer converge. This degree of conversion is known as the "bead identity point".

Suitable bases are, for example, alkali hydroxides or oxides, such as sodium, Potassium and lithium hydroxides or oxides} alkaline earth hydroxides or oxides, such as calcium, strontium and barium hydroxides or oxides; quaternary tetraalkylammonium compounds, such as tetramethylammonium hydroxide, Tetraethylammonium hydroxide and tetra-n-propylammonium hydroxide, and the alkali salts of weak acids with a PK value of at least ', 12, such as trisodium phosphate, sodium aluminate and sodium meta-silicate. The alfcal oxides and alkaline earth oxides are next to them corresponding Hydroxides can be used because these oxides enter the in an aqueous medium Hydroxides are converted «The bases are used in sufficient quantities

χ for further details of such a measure " ₁₀ _ see also the IJS-Eatentsohrift 5 288 731 —τ—""

-. 10 - ■ ■. .

used to free the polymer obtained practically completely to keep from residual acrylonitrile.

The first curve 1 is also used a base in the polymerization, it is DER Fig decisive to the necessary minimum amount of acrylonitrile in the Mönomer feed for the production of Mischpolymerisatteilchen having an acrylonitrile content of 28.5 wt -. To determine ° Jo.. . If no base is used, the second curve applies. In each case, the ratio of the acrylonitrile content in the monomer to the water content of the feed of water and monomer mixture can be expressed by the equation 2X + C = -, 7-5Y, where Y is the parts by weight of acrylonitrile per 100 parts by weight. Parts of monomer mixture and χ stands for parts by weight of water per 100 parts by weight of water-monomer mixture. The constant C corresponds to 118.75 if base is used during the poljuerization and 107.5 if no base is used.

For example, using the curves, the following ratios of acrylonitrile loading can be shown to / water with an accuracy of about + 0.5 wt.

f - '"■■■■ -' ■ ',' ■ ■ - ': ■ ■': ■. '.' ■■ -. '■ -' '. ■■■■■ ■' '■." ■ share determined v / ground which leads to an acrylonitrile content; the polymer

, particle of 28.5 wt. -f o lead.

Parts of acrylonitrile per 100 parts of parts of water per 100 parts of monomer mixture of water-monomer mixture

treated with base untreated ■ "■ '.'". "■ - - - 11 - 35.8 54.5 75 34.5 33- .. \; ■■ .- ■ 70 32.5 31 : · 62.5 • 30.5 29 ■ ■ '■: ■; ⁵⁵ ■ "- '■■ - ■ _-..-

009814/1890,

All known, usually liquid, aliphatic. Blowing agent that boil below the softening point of the polymer can according to the invention be used. For example, aliphatic hydrocarbons such as pentane, isopentane, hexane, cyclohexane; Halogen-containing aliphatic hydrocarbons, such as ethyl chloride, propyl chloride, isopropyl bromide, Isopropyl chloride, dichlorodifluoromethane, trichlorofluoromethane, 1,1,2-trichlorotrifluoroethane etc. are expediently Blowing agents used, which show less tendency to evaporate from the copolymer. Isopentane, for example, can be left on the Retain small polymer particles as n-pentane. The blowing agents are used in an amount of about 3 to 20 weight percent based on weight the monomer feed. As it proved difficult has to impregnate acrylonitrile-containing copolymers with blowing agents after the polymerization, the blowing agent is expediently used added to the monomer charge before the start of polymerization.

In order to initiate and carry out the polymerization, conventional, Free radical generating catalysts are used. Such catalysts are, for example, organic peroxides such as lauroyl peroxide, benzoyl peroxide and other free radical initiators such as azo-bis-isobutyric acid nitrile.

It has been found that the expandability of the polymer particles can be significantly improved if the molecular weight of the polymer by a chain transfer agent, such "as iodine or Dodecylbenzylmercaptan _p limited. For example, permits the addition of

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009 81A / 1890

- - ^; - - 12 - - ζ ''; ■ '■■■'. ■■■ '"..

0.1 wt .- ^ iodine (based on the weight of the monomer) the production of foamed particles with a bulk density of only 0.0240 g / ccm. It has been shown that, for example, a copolymer with the same. Monomer ratio and the same amount of blowing agent, but without iodine, can only be expanded to a density of about 0.0481 g / ccm. The chain transfer agent is expediently used in amounts of about 0.05 to 0.25% by weight , based on the monomer charge, since amounts smaller than 0.05% by weight do not have any great influence on the expandability of the product. If the concentration is increased above 0.25% by weight, the polymeric foams made from these particles tend to shrink excessively.

The presence of a plasticizer, such as, for example, 1 or 2% by weight of residual styrene, or an inert plasticizer, such as, for example, ethylbenzene, also increases the expandability of the polymer particles, but has a somewhat lower effect than the chain transfer agent. The plasticizer should be used in amounts not exceeding about 2.5 % ; the foam shrinks at higher concentrations. In addition to styrene monomers and ethylbenzene, suitable plasticizers are compounds of low volatility, which are known to be effective plasticizers for styrene polymers, such as mineral oil, butyl stearate, chlorine-containing diphenyl or the like , O16O g / cc can be obtained.

- 15 ■ »

009814/1890

The polymerization temperature must be so high that the polymerization is proceeding at an acceptable rate but should be controlled to prevent excessive hydrolysis of the acrylonitrile will. Polymerization temperatures between around 65 and 100. The polymerization takes place under autogenous pressure or slightly increased pressure by adding an inert gas, e.g. Nitrogen.

To produce a polymer that is practically free from residual Acrylonitrile and showing no discoloration is preferred during a base was added to the polymerization.

The following examples serve to illustrate the invention Procedure. All parts mentioned in these examples are parts by weight.

Example 1. » .

In a reaction device with a capacity of about 19 liters, which has a three-winged Containing stirrer, 0.52 parts by weight of a suspending agent (Gantrez AN-159, an equimolar, non-neutralized copolymer of methyl vinyl ether and maleic anhydride with a specific Viscosity of 1.0 at 25 °, measured with 1 g of polymer in 100 ecm Methyl ethyl ketone) given in the form of a fine powder. Then were 150 parts of water were added and the suspending agent was mixed with the Water 5 minutes at 150 rpm. stirred to a completely wetted Prepare a slurry of the suspending agent in water. Sann were The following compounds were added in the order given: 62.5 parts

Styrene and. 37 »5 parts of acrylonitrile, _ a catalyst from a.-. Iniaeh'ung of 0.86 part of lauroyl peroxide and 0.21 part of benzoyl peroxide, a plasticizer (2.1 parts of ethylbenzene) and 0.11 part of iodine as a chain transfer agent. The reaction apparatus was purged with nitrogen and then 15 parts of isopentane was added as an expanding agent. The suspension was stirred at 200 rpm, heated to 75 for 1 hour, kept at 75 ° for 2.8 hours and then treated with 1.1 parts of sodium hydroxide in the form of a 10% aqueous solution. The sodium hydroxide was added to destroy the acrylonitrile remaining in the aqueous phase so that the product did not contain any unreacted3 acrylonitrile. The suspension was heated to 75 for a further 3/2 hours; then the temperature was raised to 85 in 0.5 hour and held at 85 for 2 hours to complete the polymerization. The reaction mixture was cooled to less than JO and withdrawn from the reaction device. The fine suspension obtained in this way was thixotropic and flowable and had a solids content of 39.2% by weight, a Brookfield viscosity of 110 centipoises (with spindle no. 1 at 12 rpm) and a pH of 10, 5. A portion of the fine suspension thus obtained was then filtered with the aid of a vacuum through a sieve with a mesh size of 0.037 and dried in the air for 6 hours. The dried particles contained 13.2 wt .- ^ volatile materials, 0.1 wt .- # residual acrylonitrile ₉ 0 »2 wt .- $ residual styrene and 32.4 wt .- # bound acrylonitrile. The particle size distribution was determined by sieving, and the following results were obtained?

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009814/1890

Particle size, ~ "° *" ; ../,, "';,; .. ■; -." · -.', / Screen mesh size in mm wt. -

A + 0.42 2.0

B -0.42 + 0.297 6.1

C - 0.297 + 0.210 16.2

D -0.210 +0.149 31.5

E -0.149 + 0.074 34.0

F - 0.074 + 0.044. "- '" * ■ ■ ₈ ^ ₂

Q - 0.044 + 0.037 ^J 2 ', 0

Aliquots of the dry particles were expanded by placing a 1 gram sample in an aluminum weighing pan on the top of a water bath containing boiling water for 2 minutes. The samples of different particle sizes expanded to bulk densities between 0.0367 ^and 0.0143 g / ccm, as summarized below »

Particle size., ^^ "------

Screen mesh size in-mm .... ►., ^, ^, ^^ ;, ^: - g / ccm ,, . "'....

C - 0.297 +0.210, - O, Oi43 ,,

D -0.210 + 0.149 .. ^ O.0.0150;

E, - 0.149 + 0.074 x 0.0256

P -0.074 + 0.044 0.0367

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0 09.814 / 189.0

Example 2 .

A bottle with a capacity of about 340 g was charged with the following reactants in the order given: 100 parts of water, 0.5 parts of suspending agent (Gantrez AN-139; specific viscosity = 1.2, measured with 1 g in 100 ecm of methyl ethyl ketone at 25 °) , 33 parts of acrylonitrile, 57 parts of styrene, 10 parts of cC-methylstyrene, 0.80 part of lauroyl peroxide and 0.2 part of benzoyl peroxide as a catalyst, 14 parts of isopentane as a blowing agent and 0.25 part of dodecylbenzyl mercaptan as a chain transfer agent. The bottle was sealed and turned in heated to 75 ° in an oil bath for 8 hours. After 6.5 hours at 75 °, the contents of the bottle were cooled to 25 to 30, and 1 part of liatric hydroxide was injected into the bottle in the form of a 20-fold solution. Cooling was necessary to avoid loss of suspension as the bottle had to be removed from the rotating device to add the sodium hydroxide. In the case of a reaction device equipped with a stirrer, such as that of the example »!, cooling is not necessary, since the sodium hydroxide can be added with continued stirring. Once the bottle had been heated to 75 ° for a total of 8 hours, the temperature of the oil bath was raised to 85 ° for 2 hours to complete the polymerization. The product was a whitish, creamy, pourable, fine suspension with a pH of 9.1. Analysis of the dried particles showed a content of residual styrene and acrylonitrile of less than 0.1% by weight each, a content of bound acrylonitrile of 28.5% by weight and a volatile matter content of 11 »6% by weight - · - ;; '·.'. """■" ■ '■ .. ■ -:> ■■ -.' ■■■

■ '■■■■. ■'"-.-'V■■.' - ■ ■ .: '> 17 -

009814/18 90

Samples of the fine suspension were expanded by adding 45 ^CGa aqueous suspension to 500 cc of boiling water in an uncovered 800 cc Beoher glass and stirring for 1 minute. The beaker was allowed to cool until the contents could be processed, and then the contents were poured through a 0.044 fflni mesh screen. The foam particles were poured from the sieve into aluminum dishes lined with paper towels and allowed to dry there until they were free flowing, which took about 24 hours. The particles had a bulk density of o.037Q1 g / ccm.

Example 3

A bottle with a capacity of about 340 S was charged with the following reactants in the order given: 120 parts of water, in which 0.4.8 parts of Gantrez AN-139 (specific viscosity => 1.2, measured with 1 g in 100 ecm methyl ethyl ketone at 25 ) were slurried, a monomer mixture of 51 »98 parts of styrene, 0.02 part of divinylbenzene and 28 parts of acrylonitrile, in which the catalyst system consists of 0.64 parts

and lauroyl peroxide and 0.16 part of benzoyl peroxide was dissolved / 0.08 part Iodine as a chain transfer agent and 0.8 part of ethylbenzene as a plasticizer, and 11.2 parts of isopentane as a blowing agent. The bottle was sold

closed and rotated in an oil bath at 75 for 5 hours. After 3 hours at 75 ° the bottle was cooled to 25 ° to 30 °, and with the help a syringe was 0.8 parts sodium hydroxide as 20 aqueous solution added to the bottle. After the bottle 5 hours Had been heated to 75 in the oil bath, the temperature of the oil bath became Increased to 85 ° for 2 hours to complete the polymerization. That

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009814/1890

The product was a creamy, pourable, fine suspension of white to whitish color. According to analysis, the dried particles contained .The following ingredients: 0.1 wt .- £ residual styrene, 0.1 wt .- ^ residual acrylonitrile, 30.5 weight - "/>'completely bound acrylonitrile and 12.7 wt?.. -fo volatiles. a portion of the fine suspension was expanded according to the method of example 2. the expanded particles had a bulk density of 0.0304 g / cc.

Example 4 . ·

An approximately 340 g bottle was made with the following reactants charged in the order listed: 120 parts of water, 0.32 parts Gantrez AN-I69 (specific viscosity ■ 3 »5» measured with 1 g copolymer in 100 ecm methyl ethyl ketone at 2p) in the form of a fine powder, 28 parts of acrylonitrile, 52 parts of styrene monomer, 0.64 part of lauroyl peroxide and 0.16 parts of benzoyl peroxide as a catalyst, and 11.2 parts of isopentane as a blowing agent. They were also used as chain transfer agents 0.08 part of iodine and 1.6 parts of ethylbenzene were added. The bottle was closed and heated in an oil bath for 2 3/4 hours at 75 ° while rotating. Then the contents of the bottle were cooled to 25 ° to 30 °, and With a syringe, 0.8 parts of sodium hydroxide were obtained in the form of 20% aqueous solution injected. The bottle was reheated to 75 and kept at this temperature for an hour, after which the temperature was increased to 85 within half an hour. The temperature of 85 was held for an additional hour. The product was a white pourable, fine suspension. The polymer particles were filtered off and air dried. The foaming according to the procedure of Example 1 provided particles with a bulk density of 0.0256 g / ccm.

009814/1890

Example 5

In an approximately 340 g bottle was placed 60 parts of water, in which 0.81 parts powdered Gantrez AN-1J59 (specific viscosity of 1.2, measured with 1 g in 100 ecm methyl ethyl ketone at 25) slurried was. The monomer preparation was then made from 78 parts of styrene and 42 parts of acrylonitrile added, in which 0.97 parts of lauroyl peroxide and 0.24 parts of benzoyl peroxide and 0.12 parts of iodine and 16.8 parts of isopentane and 2.4 parts of ethylbenzene were dissolved. The bottle was closed and heated to 75 for 2 5/4 hours while rotating in an oil bath. After 2 hours the contents of the "bottle were cooled to 25 ° to 30 °, and there were 1.2 parts of sodium hydroxide in the form of a 20% aqueous solution injected. The bottle turned on for another hour heated to 75, and then the temperature was increased to 85 for 1 hour, to end the polymerization. Thereupon was the bottle and its contents cooled down. The product was a white, pourable, fine suspension of small polymer particles.

Example 6

To show the effect that iodine as a chain transfer agent on the Expandability of the copolymer particles according to the invention from * exercises, a number of copolymers have been produced in which Iodine was also used in amounts between 0.05 and 0.15% by weight. the Polymers were made using the procedure described below produced, whereby only the amount of iodine was varied »

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00S8U / 1890

The following reactants were placed in an approximately 340 ig bottle in the order given: 100 parts V / aaser, 0.5 part powdery Gantrez AN 159 (specific viscosity 1.2, measured with 1 g in 100 ecm methyl ethyl ketone at. 25 °), 35 parts of acrylonitrile, 65 parts of styrene monomer, 0.80 part of lauroyl peroxide and 0.2 part of benzoyl peroxide as a catalyst, 14 parts of isopentane as a blowing agent and X parts of iodine as a chain transfer agent, where X is 0.05 to 0.15 wt. ^ stands. The bottle was capped and, while rotating, heated to 75 ° in an oil bath for 5 hours. After 3.5 hours at 75 °, the bottle was cooled to 25 °, and it was injected 1 part of sodium hydroxide as a 20 follow aqueous solution. After the bottle had been heated to 75 ° for a total of 5 hours, the temperature of the oil bath was increased to -5 ° for 2 hours to complete the polymerization. The bulk densities of the copolymers obtained in this way can be seen from Table I. The polymers were expanded by adding 45 ecm of the suspension to 500 ecm of boiling water and stirring for one minute in an open 800 cc beaker. The polymer particles were filtered off and air dried on aluminum dishes lined with paper towels until they were free flowing.

Weight
re Tabel I. Bulk density
d. foam
R / ecm attempt . —Yo iodine,
.admonomers Gew.-Yo Suspendier
medium, badMonom. 0.04486 1 0.05 0.6 0.05685 2 0.075. 0.6 0.03044 3 0.10 0.6 0.02563 4 · 0.15 0.6 - 21 -

Q098H / 1890

The table shows that with an increasing amount of iodine, the expandability the number of particles increases, which is evidenced by the lower bulk density of the foam produced. ■

Example 7

To see the effect of various plasticizers on the expandability of the To show mixed polymer parts, a series of experiments were carried out according to the following procedure, in which the values listed in Table II combined amounts of plasticizers were used.

In a bottle with a capacity of about 340 S , the following reactants were given in the order given 120 parts of water, 0.5 part of powdery Gantrez AN 139 (specific viscosity * 1.2, measured with 1 g in 100 ecm of methyl ethyl ketone at 25) as a suspending agent, 28 parts of acrylonitrile, 52 parts of styrene monomer, 0.80 part of lauroyl peroxide and 0.2 part of benzoyl peroxide as catalyst, 11.2 parts of isopentane as blowing agent, 0.08 part of iodine as chain transfer agent and the amount of plasticizer given in Table II. The bottle was capped and heated to 75 for 5 hours while rotating in an oil bath. After 3.5 hours at 75 °, the bottle was cooled to 25 ° to 30 °, and 1 part of sodium hydroxide in the form of a 20% aqueous solution was injected into the bottle. After the bottle was heated to 75 for a total of 5 hours, the temperature was increased to 85 for 2 hours to complete the polymerization. The copolymer particles were expanded by adding 45 ecm of the suspension to a boiling point of 500 ecm

(800 ecm) water and 1 minute in an uncovered beaker / stirred. the

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00 9 8 U / 1 8 9 0

expanded particles were filtered off from the water and attached to the Air-dried in paper-lined alucini bowls. The bulk weight of the expanded polyamide particles is shown in Table II see.

Table II Plasticizers Gevi.- ^c / o soft
macher, re.
d.monomers Schüttgev /.
d. foaming.,
tf / ccn attempt no '- - 0.03044 1 Ethylbenzene 0.55 0.02884 2 Ethylbenzene 1.1 0.02723 5 Ethylbenzene 2.5 0.01762 4th n-butyl stearate 1.1 0.02884 5 n-butyl stearate 5.5 0.14418 6th chlorinated diphenyl 1.0 0.02884 "- 7th chlorinated diphenyl 5.0 0.04486 8th

The results in Table II clearly show that the density of the Foam with increasing amount of plasticizer up to 2.5 wt .- $ decreased, however, that the use of 5.0 to 5.5 wt .-% plasticizer led to an increase in the bulk weight, since the so obtained foams collapsed.

0098U / 1890

■ - 23.- ■ -V ·

Example 6 ';

A number of experiments were carried out to determine the effect of the crowd to determine the particle size of suspending agent. AI3 suspending agent was Gäntrez AK 159 (specific viscosity of 1.2, measured with 1 g in 100 ecm methyl ethyl ketone at 25) used in the form of a powder. The following polymerization process was used in each case, only the amount of suspending agent varied between 0.2 and 8% by weight.

80 parts of water, in which X parts of powdery Gantrez AN 139 were slurried, were placed in an approximately 34Ο g bottle; X stands for the amount specified in Table III. Suspending agent. Were then, the monomer mixture of 78 parts styrene and 42 parts of acrylonitrile was added in the O _r 97 parts of lauroyl peroxide and 0.24 parts of benzoyl peroxide as a catalyst, 0.12 parts of iodine and 16 ₉ 8 parts of isopentane dissolved. The bottle was capped and rotated at 75 ° for 2 hours in an oil bath. After 2 hours, 1.2 parts of sodium hydroxide in the form of a 20% aqueous solution were injected into the bottle. The bottle was then heated to 75 ° for a further hour and then to 85 ° for 1 hour in order to end the polymerization. After cooling, the contents of the bottle were passed through a 0.037 mm mesh screen and air dried in aluminum dishes until the particles were free flowing. The results of the tests are summarized in Table III.

"24 -

009814/18 9 0

Table ΙΙΓ

ο 3 ο co 4th OO 5 6th OO co 7th 6th

.- $ suspending agent, test on weight of monomers

P, 2

0.4

0.6 O, β 2.0. 4.0 6.0 8.0

Effect of the difference !. Amounts of
Gantrez AN 139

Pourable fine suspension »slightly granular

Pourable fine suspension, very light, granular

Pourable fine suspension Pourable fine suspension Pourable fine suspension Pourable fine suspension Pourable fine suspension

Weight .-? O of the particles, T-pocket width in r

-0.297 -0.210
+0.210 ' +0.074

62

-0.074 -0.044
+0.044 +0.057

traces

39 59 2 9 1.0 . traces ro 23 67 8th 2 ι 24 66 7th 5 11th 78 10 1 18th 73 traces 3 87 traces

Weight-fo on a sieve of a mesh size
of 0.297 mra

ro

CO CO CD CT) CD

The table shows that when more than 6.0 wt. - ^σ β> suspending agent is used, the particle size increases so much that the particles grow beyond the desired size range of less than 0.297 mm.

Example 9

In order to show the retention of the blowing agent by the fine suspensions according to the invention, portions of the particles produced according to Example 1 were left to stand in the air. The original content of the particles, of volatile substances was determined by separated out the particles from the suspension and dried in air until they were free-flowing, after which 1 g of heavy samples of the particles heated for 1 hour on I5O ⁰ and 'then examined for weight loss became. The initial volatile content of the particles was 13.2 Gevf. "io. After 8 days, still 15.2 wt .- ^ containing the particles volatiles. After 16 days, the volatiles Genalt was 13.1 wt .- $, after 31 days 13.0 wt .- $ and after 65 days $ 12.5 wt.

Example 10

The following reactants were placed in a bottle of about 340 g in the order given: 150 parts of water, 0.5 parts of Gantrez AN 16 $ (specific viscosity of 3 * 0 »measured with 1 g in 100 ecm of methyl ethyl ketone at 25) in the form of a dry powder, 32.5 parts of styrene and 17.5 parts of acrylonitrile, in which 0.3 part of azo-bisisobutyrnitrile was dissolved as a catalyst and 70 parts of isopentane as a blowing agent. The bottle would be closed with a crown _cap

0098 U / 1890 -

- 26 - "■ '■■.:: ■ _ ■ -; -

and heated to 75 in an oil bath while rotating for a total of 3 hours After 2 hours at 75 ° the contents of the bottle had decreased to 2p-J0 and with the help of an injection syringe, 5 Torlo Xatriuahydroxyd given as 10% aqueous solution in the bottle., liachdea the Bottle has been heated to 75 ° for a total of three hours, was dio Temperature of the oil bath increased to 85 ° to boondon the polymerization The end product was a creamy, gioasable, fine suspension. Obtained polymer particles containing 6.3 wt .- $ volatiles based on the weight of the copolymer solids, contained Expansion according to the procedure of Example 2 gave the product a Bulk density of 0.1137 g / ccm.

Example 11

To show what effect the amount of acrylonitrile in the copolymer has on the retention of the blowing agent in the fine suspension, a number of copolymers were produced which contained different amounts of acrylonitrile by adding between -20 and 50 wt. - ^ Acrylonitrile based on the weight of the styrene monomer used. The same conditions and loads were used and only the amounts of acrylonitrile were changed. The feed consisted of 150 parts v / water, 50 parts styrene-acrylonitrile, which measured 0.3 part of azo-bis-isobutyrnitrile, 0.5 part of powdered Gantrez AN 139 (specific "viscosity of 1.4, measured

contained 1 g in 100 ocia methyl ethyl ketone at 25) / and 6 parts isopentane

Blowing Agent The bottles with the charge were taking

Turning "Heated a total of 3 hours in an oil bath at 75 °. The contents of the

0098U / 1 890

around dia Uariaontalachoe

Bottles were cooled to 25-30 ° after 2 hours at 75 ° and 0.5 part of sodium hydroxide was injected into the bottles in the form of a fig wii solution. The polymerization was terminated by increasing the temperature of the oil bath to 85 ° for 2 hours. The volatile content of the dried product was determined as follows: a thin film was poured onto filter paper and most of the water was removed by vacuum. The filter paper was air dried for 5½ hours at which time all powder samples were free flowing. Then, 1 g of heavy samples of the powder were heated for 1 hour in an air oven at I50 ^0th The volatile content of the product, which was determined by the weight loss of the samples, is shown in FIG. 2, in which the volatile content was plotted against the percentage acrylonitrile content of the styrene-acrylonitrile monomer charge. Ea is clearly shown that -fo acrylonitrile in the comonomer feed zweökmässigerweise at least 35 wt. Should be present. '

Example 12

This example shows that fine suspensions can be made

by slurrying the suspending agent in the monomer mixture.

-The following reaction parts * · given in the order listed: HO parts of water and one Monomer mixture of 39 parts of styrene and 21 parts of acrylonitrile, in the 0.36 part of azo-bis-isobutyrnitrile as a catalyst and 0.05 part of iodine as Dissolved chain transfer agent and 0.3 part powdered Gantrez AN

; - 28 -

009814/1890

139 (specific viscosity of 1.0, measured with 1 g in 100 ecm methyl ethyl ketone at 25 °) were slurried. Then 8.5 parts of isopentane was added to the bottle as a blowing agent. The bottle was capped and heated to 75 ° in an oil bath while rotating for 2 hours, after which the contents of the bottle were cooled to 25-30 °. Then 0.6 part of sodium hydroxide in the form of a 20 % aqueous solution was injected into the bottle. The bottle was again heated to 75 ° for 1 hour and finally to 85 ° for 1 hour. The product was a creamy, fine product Suspension of fine polymer particles.

Example 15 '

About the effect of different expanding agents on the Expandierbärkalt To compare the product with each other, the procedure of the Example 10 repeated, but with 50 parts each of the monomers 7 parts of isopentane respectively. 7 parts of n-pentane were used. The expandability was determined according to the procedure of Example 2. the Results are summarized in Table IV.

Blowing agent

Isopentane

n-pentane

led

lot

in Wt .- ^

7 7

Table IV

Volatile substances by weight, or dry polymer by weight

9.5 8.5

Schjitt weight of the foam, g / ccm 0.0'2884 0.05767

The table shows that isopentane is retained in larger quantities by the polymer and provides better expandability.

+ around the horizontal axes

Q098U / 1890

-29 -

1930696

-29— "■ - ■; ■■ ■; ■■■; ■■ .. - ;.; /..

Example 14 *

To illustrate the effect achieved when a solution of the suspending agent is used instead of an aqueous slurry of the suspending agent used as a fine powder, an approximately 340 g bottle with 187.5 parts of water, 32.5 parts of styrene, 17.5 parts Acrylonitrile, 0.3 parts of azo-bis-isobutyrnitrile charged as a catalyst and 7 parts of isopentane as a blowing agent. As a suspending agent, 0.25 part of Gantrez AN 139 was dissolved in 12.5 parts of water at 90.degree. aqueous solution was added to the feed. The bottle was sealed and ^{heated to 75 ° for 2 hours while turning +} in an oil bath. "After 2 hours the contents of the bottle were cooled to 25-30 ° and 0.5 parts of sodium hydroxide in the form of a 20% aqueous solution were added The solution was injected into the mixture. The mixture was then heated to 75 ° for a further hour and, to complete the polymerization, 1 hour to 85 °. The product thus obtained was a large lump of polymer. '- *. ".. **'"

Example 15 ;

Attempts have been made to use finely divided: expandable polymer particles Using known suspending agents for styrene polymerizations. The procedure described below was used in all experiments and only the suspending agent was changed.

In an approximately 340 g-capped bottle 150 parts of water, 32.5 parts of styrene, 17.5 parts Aoirylnitril, 0.3 parts of azo-bis-isobutyrnitril added and • 14 parts liopentan as a blowing agent * The bottle was verschlos-

sen and heated for 2 hours in an oil bath at 75 ° while rotating. To 2 hours the contents of the bottle were cooled to 25-30 °, and it 0.5 parts of sodium hydroxide were added to the bottle as a 10% aqueous solution injected. Then the bottle was set to 75 ° and for a further hour heated to 85 ° for 1 hour to complete the polymerization. The suspending agents used and the results of the experiments are off Table V can be seen.

Table V Suspending agent Weight-5ε, re.
ad monomers 1. Hydroxyethyl cellulose 1.0 2. polyvinyl alcohol 1.0 j »polyacrylamide 0.5 4 β sodium polyacrylate 0.5 5 · polyethylene oxide 0.5 6. Alginic acid 0.5 7 · polyacrylic acid 0.5

Θ. Styrene-llaleinic anhydride

Hischpolymerisat (1 »1) 1.0

' Result .
Spheres +0.42 mm Spheres +0.42 mm agglomerated spheres Polymer lumps Polymer lumps Polymer lumps' Polymer lumps

Polymer lumps

Example 16

A part (63Ο. Parts by weight) of the fine prepared according to Example 1 The suspension was brought to pH 6.5 with glacial acetic acid. the fine suspension, which "I in a" provided with a cooling jacket Vessel was agitated at high speed while 25.6 Parts of polyvinyl alcohol were added. The stirring was 15 to 20 minutes

- "3TV

The grooves continued to carefully disperse the polyvinyl alcohol in the slurry. The slurry was cooled to pass through the. Stirring device to dissipate mechanically generated heat and to keep the temperature below 35 °. After the polyvinyl alcohol had dispersed in the fine suspension, which took 1/2 hour, 256 parts of a styrene-butadiene latex (50 wt .- $ _; solids, 60 $> bound styrene) were quickly stirred in. The temperature was maintained between 30 and 35 and stirring continued until a smooth, creamy mixture was obtained} which was about 1 hour after the latex addition had started. The pH of the mixture was 6.6. A portion of the mixture was applied as a coating to Kraft paper with a 0.152 mm pull rod. The coated paper was then heated to 110 in an air oven for 20 minutes to dry, expand, and cure the coating. The coating thus obtained showed excellent adhesion to the paper, satisfactory flexibility and a thickness of 0.508 mm. The bulk density of the coating was 0.2323 g / ccm. '**

Example 17

A portion of the dried particles of Example 1, which as subset D (-0.210 '+ 0.0149 mm) and have a bulk density of 0.0151 g / cc had been expanded between two sheets of Kraft paper given. The thickness of the bead layer was about 1.59 mm. The paper and beads were placed between heated platens and heated to 120 ° so that the particles expanded, the empty spaces the -. globule layer filled and on each other as well as on the -

', ■ "■■: ■ - '■" ■ '' - 32 -

00981A / T890

- 52 ■ -

Paper stuck. It got good adhesion to it. Paper and good amalgamation of the beads achieved with each other. The product thus obtained was flexible and could be used as an insulating packaging material will.

The product according to the invention is suitable for many purposes. The dried, expandable polymer particles can be used as cheap, light, extremely finely divided load-bearing fillers or core and / or. Inner material with excellent insulation properties can be used. For example, they can be mixed with paper pulp, cement, bricks, etc. and processed into packaging or building material. Due to their small particle size, the products according to the invention can be mixed with latices either in the form of a dry powder or as an aqueous suspension (conveniently in the suspension in which they were produced) and used as dipping baths in the production of fabrics for blankets, clothing, shoes or upholstery material will. They can be mixed with latices and then provide insulating, impact-resistant coatings on metals, wood and other substrates. When combined with thermosetting resins, they are also suitable as lightweight, insulating fillers.

- 55 -

0098U / 1890

The present description explains the production of finely divided, expandable polymer particles that retain their expandability indefinitely, despite their small particle size, if they are kept in suspension or separated from the suspension and ala dry pesticide can be stored. The particles are larger than Latex particles, but smaller than those with previously known suspensions ^ polymerisation systems, and thus small enough to be suitable for uses that require a finely divided, require expandable, thermoplastic material.

0098 U / 1890

Claims (3)

- '■■■■ - * 1. Process for the production of finely divided, expandable "ar er Vinyl aryl nitrile copolymer particles. a predominantly rope size between about 33 and 296 », characterized in that msn a) in an aqueous medium, for example. 0.20 Ms β, Q wt. - / -, based on the total weight of the monomers, one unneutralized Equinolar copolymers of methyl vinyl ether and Kai monoic anhydride in Perm one fine powder on slurries and an aqueous suspension the insoluble glow forms j b) adding the following compounds to the suspension; -a vinyl aryl monomer in an amount of at least about 50% by weight, based on the total weight of the IConomers, - an acrylonitrile monomer in a sufficient amount, to copolymer particles with an acrylonitrile content of at least about 28.5 wt. - ^c j> to provide -a free radical generating catalyst, -about 3 to 20 wt .- $, based on the weight of the monomers, a volatile blowing agent, and c) the suspension is heated under preferably autogenous pressure to tensile v * · · about 65 ⁰ O Ms 100 ⁰ O in order to poly- ^{white the monomers} merize. . · of the procedure 2. embodiment / according to claim 1, characterized in that _a that before heating an aqueous. Suspension by suspension a mixture of the viaaylacryl monomers, acrylonitrile monomers, the free Badücale-generating catalyst, of the volatile blowing agent and the copolymer of methyl vinyl ether and maleic anhydride isrgestell will. . '. 3. Finely divided, expandable vinyl aryl -acrylonitrile 1- . Liischpolymerisatteilchen with a predominantly! Ceilchen size between about 33 and 296yu manufactured after that Method according to claim 1 or 2. . 0098U / 18ÖÖ Lee rs e ι te