DE3223847A1 - METHOD FOR IMIDATING A METHACRYLATE OR ACRYLATE POLYMER - Google Patents

Description

AD 5085 -3-

.

description

The invention relates to a method for imide formation of acrylic polymers and in particular a continuous process that operates in one inside with Partitions provided pipe is carried out.

Methyl methacrylate (MMA) homopolymer and copolymers with e.g. acrylates, styrene or butadiene can be one Imide formation can be subjected to by reaction of the polymer with ammonia or alkyl or aryl amines, among Formation of imides as represented by the following equation:

-CH ₂ C-CH ₂ -C- - ^ - CH ₂ -CC

OO 0 »C • • OR ¹ OR ¹

R "

The cyclic imide polymers can also be obtained by heating selected amides or nitriles. Most such processes are operated on a rudimentary basis. In

More recently, there has been a continuous imidization process in U.S. Patent 4,246,374 in which a methacrylate or acrylate polymer vented into one Screw extruder (screw extruder) with

an amine is used and the imide during the Be-35

movement of the materials through the extrusion press

-3-

AD-5085 -4-

elevated temperatures under essentially anhydrous conditions.

A new continuous process for the imide formation of methacrylic and acrylic resin has now been found, that does not require the use of a screw extruder and that allows the temperature and pressure can be controlled more carefully than with a screw extruder.

The new process is a process for the imide formation of a methacrylate or acrylate polymer, which consists in after another

a) a molten methacrylate or acrylate polymer with ammonia or a primary alkyl or aryl amine to mix

b) introducing the molten mixture into a tubular reactor provided with dividing or baffle walls, which results in a dispersed plug flow,

c) the temperature of the mixture inside the tubular Raise the reactor to 200 to 300 ° C and

d) passing the molten mixture through the tubular reactor for a time which is appropriate is to complete the imide formation, but less than to substantially decompose the polymer needed.

The polymer to be imidized is an acrylic and / or methacrylic polymer. It contains neighboring Units of

-A-

AD 5085 -5-

C = O
ι

R ¹

wherein R is -CH ₃ or -H and R ^{1 is} alkyl of 1 to 10 carbon atoms. These polymers can also contain units derived from up to 40% by weight of methacrylic acid or acrylic acid, styrene, butadiene, ethylene or acrylonite and the like. Polymers containing at least 75% methyl methacrylate are preferred. The molecular weight of the polymers can vary over a wide range. Those with an inherent viscosity of

! 5 at least 0.3, measured in a 0.5% solution of a Mixtures of methanol and methylene chloride (20/80) at 25 ° C are preferred. That to be subjected to imide formation Polymer can be used in any form, but generally the polymer is in the form of Powder or granules before melting.

The ammonia or primary alkyl or aryl amine that is used is generally of the formula R ¹¹ NH ₂ , where R "is -H, alkyl of 1 to 12 carbon atoms, cycloalkyl of 7 to 11 carbon atoms, or aryl having 6 to 10 carbon atoms, preferably phenyl.Examples of amines which are useful here include methyl, ethyl, n-propyl, η-butyl, heptyl, hexyl, octyl, nonyl, decyl,

Dodecyl, hexadecyl, octadecyl, isobutyl, sec-butyl, t-butyl, isopropyl, 2-ethylhexyl, phenethyl, allyl, Benzyl, p-chlorobenzyl, and dimethoxyphenethylamines; and also alanine, glycine, 3'-aminoacetophenone,

2-aminoanthraquinone and p-aminobenzoic acid. Others 35

suitable amines are cyclohexylamine, 2-amino-4,6-

-5-

AD 5085 -6-

] dimethylpyridine, 3-aminophthalimide, 2-aminopyrimidine, 2-aminothiazole, 5-aminothiazole, 5-amino-IH-tetrazole, Aniline, bromaniline, dibromaniline, tribromaniline, chloraniline, Dichloroaniline, trichloroaniline, p-phenetidine and p-toluidine.

In the process according to the invention, the polymers in molten form and ammonia or amine immediately before or immediately after entering the pipe shaped reactor mixed. There is a mixing process involves feeding the polymer into an extruder, melting the polymer and the molten one Propelling polymers into the tubular reactor. Once the polymer has melted, ammonia or Amine can be added. Care is taken to ensure that. Ammonia or amine immediately before or immediately to be added after entering the tubular reactor. An earlier addition may lead to a certain premature reaction, eliminating the careful temperature and pressure controls that are carried out by of the reaction in the tubular reactor become useless.

The reaction temperatures are as low as can be used to maintain a short reaction time and as high as can be tolerated to avoid undue degradation of the polymer to avoid. The use of a tubular reactor with dividing or baffle walls inside with high mixing effectiveness and the associated uniformity of temperatures due to the contained Materials allow the use of short reaction times at relatively high temperatures, without the risk of hot spots in the reaction medium. Such hot spots and one

AD 5Ο85 -T-

uneven radial temperature distribution lead to Decomposition of the polymer and, in addition, unusable or undesirable polymeric materials. When the dwell time of the contained materials are kept practically constant and if the temperature gradient is perpendicular can be kept very low to the flow axis, it has been shown that it is advantageous the reaction at high temperatures for a short time as opposed to low temperatures for longer Time to perform.

Essential factors for the successful completion of the reaction include precise overall control or Overall control of the temperature of the reaction materials and the maintenance of a short and uniform residence time of the materials in the reactor. When there are large temperature differences within the reaction melt exist, then there are opposing degrees of reaction, i.e. an incomplete reaction in zones lower Temperature and polymer degradation in high temperature zones. In a tubular reactor, the Temperature differences perpendicular to the total material flow (radial) are reduced to a minimum. In order to keep these temperature differences to a minimum, sufficient radial dispersion of the Materials are made so that heat transfer from one location in the reactor occurs radially to another. Axial temperature control is also important in order to avoid inconsistent reaction levels that cause boi

³ ^ a varying exposure to suitable reaction temperatures could occur. A steady operating condition is necessary in order to carry out useful continuous reaction processes. A reactor that provides the necessary temperature control, the efficiency of the heat transfer and the evenness of the residence

—7 -

AD 5085 -δ-

time results is a tubular reactor in his Inside with a series of helical dividing or baffle walls or spirally arranged dividing or baffle walls is equipped with alternating opposite inclination. Such a reactor is shown in U.S. Patent 3,286 described.

In order to achieve a polymer of uniform quality, is it is important that all of the reaction material have essentially the same reaction temperatures during the is subjected to substantially the same time. this

. is defined as "dispersed plug flow". Such a dispersed Plug flow causes every element of the molten polymer during, essentially the at the same time is in the reactor and there is considerable movement of areas of molten polymer, in relation to other areas of the molten polymer in the radial direction rather than in the axial or longitudinal direction is present.

In the case of the method according to the invention, the polymer heated to the reaction temperature before entry into the reactor, and ammonia or amine are added immediately before or immediately after entry. The temperature in the reactor is maintained at 200 to 300.degree. C., preferably 240 to 280.degree. By doing Reactor, the reaction components are intimately mixed, and each material element is practically experienced

the same reaction temperature during practically the same duration. The reaction time is generally less than about 10 minutes and longer than about one Quarter of a minute. The most preferred duration is from about 5 minutes to about half a minute, with the shorter Maximum time is important to prevent excessive decomposition,

-8th-

AD 5085 -9-

Prevent crosslinking and other undesirable side reactions.

It was found that a strict temperature control, low radial temperature gradients and a uniform short residence time allow a good reaction without excessive decomposition, which is the case with the high Temperature would be expected. When the reaction is complete, the resulting imide is removed and liquid fractions are vented. The resulting imide is then cooled and cut into pellets.

The degree of imide formation of the acrylic polymer can be easily controlled in the process of the present invention and various degrees of imidization can be achieved as a function of the properties desired will. The desired degree of imide formation can easily be achieved by adjusting the reaction parameters, such as the residence time and the temperature. It is true that imide formation by the polymer is also so low like only 1% possible, but as a rule an imide formation of at least 10% is achieved, whereby a remarkable Improvement in the properties of the acrylic polymer is obtained.

There is no catalyst in the process according to the invention necessary. This has the great advantage that it is not necessary to remove the catalyst. However small amounts of catalyst can affect the

increase speed if desired.

A solvent is in the process of the present invention not necessary, and it is preferred to operate in the absence of a solvent. If desired, can

however a solvent can be used to reduce the viscosity

-9-

AD 5085

-10-

sity of the molten mass to decrease or to carry a catalyst.

Those produced by the process according to the invention Imides are useful as thermoplastic molding resins or compression molding resins and can be in the form of fibers, Pipes or films or foils and the like. Extruded or extruded. The melted resins can are produced for the production of molded articles or molded articles such as toys, writing implements, Household appliances, etc.

The process of the invention is particularly useful for the production of imides which are 1 to 40% by weight cyclic Contain anhydride units. These imides thus contain repeating units of

a)

b)

c)

GH.

-CH ₀ -C ² I.

-10-

AD 5085 -11-

wherein R has the meaning of -CH ₃ or -H; R ^{1 is} alkyl of 1 to 10 carbon atoms; and R "is H, alkyl with 1 to 10 carbon atoms, cycloalkyl with 7 to 11 carbon atoms, cyclophenyl or phenylalkyl with 7 to 9 carbon atoms, in which the phenyl groups can contain lower alkyl, lower alkoxy or halogen substituents; and in which the units of a) 20 form up to 94% by weight of the recurring units, the units from b) form 1 to 40% by weight of the recurring units and the units from c) form 5 to 80% by weight of the recurring units, the total Percent be 100%.

The following are preferred embodiments of the Invention described. In the following examples Polymers are heated and fed into and through a tubular reactor provided with dividing or baffle walls by means of the fed by a screw extruder or a screw extruder supplied power. The one inside baffled tubular reactor used in the examples, and gave dispersed plug flow was a commercial product of Kenics Corporation, Danvers, Mass., USA.

A 2.54 cm (1 inch killian) extruder with a vacuum port and a two stage screw was connected its mold exit with an adapter plate, three sections 2.54 cm (1 inch) in diameter (Kenics Thermogenizer), followed one after the other by a nozzle shape,

^ow equipped. The extruder (Killian) was used to melt the polymer and feed it into the Kenics section. A diffusion plate 0.318 cm (1/8 inch) thick with 64 openings was placed in the Kenics lead edge. This plate, used to aid mixing, was about

-11-

AD 5085 -12-

2.54 cm clinch) downstream of an injection probe which extended 0.635 cm (1/4 inch) in the melt stream (fitted into an adapter plate) and about 3.81 cm (1 1/2 inches) upstream of the first EIe-B ment of the first Kenics section. Ammonia or amine were through the injection probe or through the vent injected into the Kilian extrusion press. A sieve pack was after the last Kenics section and in front of the valve shape to support the pressure control. A heated conduit was used for conveyance the melt from the valve mold to the rear vacuum part of a Werner and Pfleiderer 28 mm Twin screw extruder (extruder) used which is used for the removal of liquid fractions

¹ ^ was. The feed inlet of the 28 mm extruder was used as a vacuum to ventilate the volatiles and the front vacuum port was used to also devolatilize the imide product. The emerging imide strand was

^ O then quenched and cut.

Unless otherwise stated, percentages relate to on weight.

Example 1_

This example shows that the imidation reaction

takes place in the tubular reactor provided with dividing or baffle walls and not in one of the extrusion presses. Two fine (DY) and two coarse (CY) with separation or Baffled plug flow mixers (Koch) replaced the guide elements (Kenics) in the first of the three Kenics sections and two coarse (CY)

-12-

AD 5085 -13-

Elements (Koch) replaced the guide elements (Kenics) in the second Kenics section. The 2.54 cm (one inch) extruder (Kilian) was operated at 144 rpm with temperature settings of 250 ° C in the rear zone, 225 ° C in the center zone, and 225 ° C in the front zone. The Kenics sections were all set to achieve a temperature of 280 ° C; and the mold valve and conduit were set at 225C. The 28 mm twin screw extruder (extruder) had a straight screw or screw. Helical shape, with the exception of a set of inverted elements between the two regular vacuum ports to make a melt seal. It was operated positions Temperaturein-at 108-135 rpm with the following: back side _f (1) = 50 ° C, (2) = 200 ⁰ C, (3), (4), (5), and form = 25O ° C .

Four approaches were made using of cyclohexylamine and polymethyl methacrylate with I.V. of 0.47 and 0.53. During approaches 1 and 2, the Amine was pumped into the vacuum port of the 2.54 cm (1 inch) extruder during runs 3 and 4 pumped into the injection probe set in the adapter plate. In runs 1 and 3 the final product was considered to be cut Pellets are isolated after volatiles have been removed from them in the 28 mm extruder. For batches 2 and 4, samples were taken from a melting thermocouple opening at the downstream end of the conduit immediately before contact with the melt

^ O with the screw of the twin screw extruder, taken. Table I shows that 63% of the amine reacted with the polymer when it was alone in the tubular Reactor was mixed (batches 3 and 4) and that only 57% of the amine reacted with the polymer when

® ° it was introduced into the Killian extruder, and that

-13-

AD 5085

-14-

Product passed through the twin screw extruder was (approach 1). Since a higher conversion was achieved in batches 3 and than in batch 1, it can be concluded from this that the reaction takes place in the tubular reactor.

Tabel

pump (900) pumped in Production % N % Amine pressure (900) Amine swiftly in Imide Conversion approach bar (psi) (ml / min) for that to the lung (900) finished poly End (900) mere g / min Per 62 12.5 38.6 duct 37.5 57,% 1 62 12.5 "+) ' 2.24 39.3 not ge 2 2.35 measure up 62 12.0 41.4 37.3 63% 3 62 12.0 ¹¹ +) ' 2.22 37.3 63% 4th 2.22

+) Could practically not be eaten, but none were Controls changed during the brief period of these states; therefore the dimensions are likely to be unchanged.

example

The same device was used as in Example 1, but only 2 DY mixers (Koch) in the Leading part of the first Kenics section to replace any Kenic elements. The 2.54 cm (1 inch) Killian extruder was at 145 rpm with temperature settings of 175 ° C (back), 225 ° C (center) and 250 ° C (Front) operated. The temperature of the three Kenics

AD 5085 -15-

Sections was set at 280 ° C. The 28 mm twin screw extruder was at Operating at 130 rpm, the following temperatures being recorded were 1 - 140 ° C (back), 2 - 245 ° C, 3 - 245 ° C, 4 - 250 ° C, 5 - 242 ° C and mold-215 ° C. Cyclohexylamine was fed into the vacuum port of the Killian extruder at a rate of 16.1 ml / min at a Pumped pressure of 55.2 bar (800 psi). A polymer that consists of units of methyl methacrylate / styrene / butadiene (70/25/5) was fed into the 2.54 cm (1 inch) extruder and it became one of volatiles Fractionally freed end product produced in an amount of 41.9 g / min, the 2.58% N (nitrogen) corresponding to 43.2%

N-Cyclohexylimide structure with a · Tg of 144 C, determined by DSC.

Example 3
20th

The same apparatus was used as in Example 1, except for the presence of two DY and four CY-Koch elements in the first Kenics section, 8 CY elements in the second and 2 CY elements in that third. The 2.54 cm (1 inch) Killian extruder was running at 144 rpm at temperatures of 250 ° C (Rear), 234 ° C (center) and 227 ° C (front). The three Kenics sections were each based on

28O ° C set: The 28 mm twin screw strand _{or similar}

press was operated at 104 rpm with temperatures of 1-153 C (rear), 2-247 ° C, 3-275 ° C, 4-277 ° C, 5-273 ° C and mold - 284 ° C. Aniline was pumped through the vacuum port of the Killian extruder at 9.5 ml / min. The polymer used was a copolymer of methyl methacrylate / methacrylic acid (87/13, IV in CH ₂ Cl ₂ = 0.53).

-15-

AD 5085 -16-

The imide product was produced at 35 g / min and contained 1.50% nitrogen corresponds to 24.6% N-cyclohexylimide of methacrylic acid.

Example 4

The same apparatus and temperatures as in Example 3 were used. ammonia

was pumped in at the adapter plate at a rate of 5 g / min. The pressure was controlled through the mold valve to a level of 137.9 bar (2000 psi). Polymer was introduced in an amount of 40 g / min. The polymer used was a terpolymer with the components methyl methacrylate / styrene / butadiene in a weight ratio of about 75/20/5 with an IV in CH ₂ Cl ₂ of 0.51. The imidized resin produced contained

4.65% N and Tg 159 ° C. 20th

example 5 ^

This example shows the reaction of cyclohexylamine and methacrylate polymers to form both cyclic Imide and anhydride units.

The 2.54 cm (1 inch) Killian extruder was running at 144 rpm with temperature settings of 250 ° C Rear, 225 C center and front zone operated. The tubular reactor provided with dividing or baffle walls, that was used had the 3 Kenics sections.

In section 1 there were the Kenics dividing or baffle walls 35

replaced by Koch DY and -CY dividing or baffle walls.

-16-

AD 5085

-17-

In section 2 was the first Kenics partition or baffle wall replaced by a Koch-CY or baffle wall. The sections were set at 280 ° C. The valve shape and the conduit were set at 225 ° C. The 28 mm W-P extruder had a straight line continuous helical or helical shape, with the exception of one set of inverted elements between the regular vacuum ports to create a melt seal and was measured at 108-135 rpm with temperature settings of 50 ° C (back), 200 ° C (center) and 25O ° C (mold) operated.

A copolymer of methyl methacrylate and ethyl acrylate (95.5 / 4.5%) with an inherent viscosity of 0.575 was fed into the 2.54 cm (1 inch) extruder at about 37 g / min and cyclohexylamine - was added at point A (the vacuum port the Killian extruder) or at point B (the injection probe) at 62 bar (900 psi) and about 10.4 g / min (22 wt%) pumped in. The imidized polymer was sampled as in the with The tubular reactor provided with dividing or baffle walls was present (point I) or after the removal of volatile components removed in the twin screw extruder (point II). The results are in listed below:

-17-

AD 5085 Polymer-
rehearse -18- Imide
Units +) Anhydride-
Units ++) Amide
Additive- - £} U! UV χ, ■■■■■ II 37.5% by weight 7.5% by weight 1 A. I. 39.3 5.2 2 A. II : 37.3 5.6 3 B. I. 37.3 5.6 4th B.

+) Imide content by nitrogen analysis and infrared spectrum.

++) Anhydride content through titration and infrared spectrum

Claims (5)

Patent Attorneys · European Patent Attorneys * *** Abilz. Morf, Grilschneder. von Wjiigcnsicin, Poslfach 86 Ol 00.8000 Munich 86 W. Abitz Oi.-Ing. D. F. Morf Dt. [Jipl.-Chcm. M. Gritschneder DipL-Phys. A. Frhr. by Wittgenstein Dr. Dip! -Chan. Postal address / Poslal Address Postfach 86 01 09 D-KOOO MiiiK-hcii "(June 25, 1982 AD 5085 EI Du Pont de Nemours and Company, Wilmington, Delaware, V.St.A. Process for the imide formation of a methacrylate or acrylate polymer Patentans ρ rüche 1.) Process for the formation of a methacrylate or imide Acrylate polymers, characterized in that one after the other a) a molten methacrylate or acrylate polymer with ammonia or an aliphatic or aromatic primary amine mixed, b) the molten mixture in a partitioned tubular reactor which has a dispersible -1-Munich-Bogenhausen, Poschingerstraße 6 Telegram: Chemindus Munich Telephone: (089) 98 32 22 Telex: 5 23 ψ)? (abitz d) • · · m 20th 25th 30th 35 AD 5085 " ² " yawed plug flow results, introduces, c) the temperature of the mixture within the tubular increases, and shaped reactor to between 200 and 300 ° C d) passing the molten mixture through the tubular reactor in a time which is suitable to complete imide formation, but shorter than that to substantially decompose the polymer needed. 2. The method according to claim 1, characterized in that in step c) at a temperature of 240 to 28Ö ° C is being worked. 3. The method according to claim 1 or 2, characterized in that that the polymer units consist of at least 80% by weight of methyl methacrylate. 4. The method according to claim 1 or 2, characterized in that the amine is cyclohexylamine or ammonium used. 5. The method according to claim 4, characterized in that the polymer units consist of at least 80 wt .-% methyl methacrylate exist. -2-