DE2755845A1 - Copolymer prepn. from alkenyl aromatic cpd. and unsatd. anhydride - with controlled rapid addn. of anhydride to impart better physical properties - Google Patents

Abstract

Prepn. of a copolymer comprises mixing (a) an alkenyl-aromatic monomer of formula (I) with (b) an unsatd. anhydride of formula: R7-C(H)n C(R8) (CH2)m-R9, at a controlled rate over 2-4 hrs. In the formulae R1 and R2 are H or 1-6C alk(en)yl. R3 and R4 are Cl, Br, H or 1-6C alkyl. R5 and R6 are 1-6C alk(en)yl, or are joined to form naphthyl. R7 and R8 together form a O=C-O-C=O gp. R9 is H, vinyl, 1-12C alk(en)yl or alk(en)yl carboxylic acid gps. one is a double bond.n is 1 or 2, depending on the position of the C=C bond. m is 0-10.

Description

Process for the copolymerization of an alkenyl aromatic

between monomers and an unsaturated anhydride.

Copolymers of alkenyl aromatic monomers and unsaturated anhydrides are well known. These copolymers include copolymers of styrene and maleic anhydride. These copolymers have a strong tendency to polymerize in an alternating manner, so as to give a product containing 50 moles of each component. These Copolymers are useful because they have a very high heat distortion temperature, however, they have a major disadvantage because of their tendency to be very brittle. On the other hand, if such a 50/50 copolymer is blended with other resins, so they generally do not form molding compounds which have satisfactory properties exhibit. Therefore, in order to obtain a product which can be processed, a Copolymer needed, which is essential less than .50 mole-7 Contains maleic anhydride.

So far, attempts have been made to determine the properties of this Improve copolymers by a process based on the very slow addition of the maleic anhydride based on a polymerization mass or solution of styrene.

This process produces a copolymer with a relatively uniform Composition and it is described in U.S. Patent 2,971,939.

It was generally assumed that the more evenly or completely at random one could obtain the styrene-maleic anhydride copolymer so as to do so better would be the physical properties of the resin obtained. In the published Dutch patent application 7 212 714 (equivalent to US patent application Serial-No. 182 893) therefore the use of very long addition times for the maleic anhydride taught in the production of high impact styrene maleic anhydride resins. In the Examples of this application are therefore maleic anhydride in methyl ethyl ketone solution added routinely within 15 to 20 hours.

Unexpectedly, it has now been found that the best physical Properties of the styrene-maleic anhydride copolymers are by no means among the slowest Addition of the anhydride can be obtained. It was found to be an optimal rate of addition for the union of styrene and maleic acid anhydride is in one area, which is much faster than what is generally considered to be necessary Has.

The process according to the invention thus creates a way for the production of a copolymer from an alkenyl aromatic monomer of the formula: where R1 and R2 are selected from the group consisting of lower alkyl or alkenyl groups with 1 to 6 carbon atoms and hydrogen, R3 and R are selected from the group consisting of chlorine, bromine, hydrogen and lower alkyl with 1 to ß carbon atoms, R5 and R6 are selected from the group consisting of lower alkyl and alkenyl groups having 1 to 6 carbon atoms, or n and n can be linked together through hydrocarbon groups to form a naphthyl group; and an unsaturated anhydride of the formula wherein the dashed lines represent either a single or double carbon-carbon bond with the proviso that only one dashed line is always a double bond and the other dashed line is a single bond, R7 and R8 together one Represent a group, R9 is selected from the group consisting of hydrogen, vinyl, alkyl with 1 to 12 carbon atoms, alkenyl with 1 to 12 carbon atoms, alkylcarboric acid with 1 to 12 carbon atoms, alkenylcarboxylic acid with 1 to 12 carbon atoms, n is 1 or 2 depending on the position of the carbon-carbon double bond and m is an integer from 0 to 10, this process comprising the combination of the unsaturated anhydride with the alkenyl aromatic monomer in a controlled addition rate which extends over a period of 2 to (3 Hours, preferably 2.5 to 4 hours.

The process is preferably carried out by adding the unsaturated anhydride to the alkenyl aromatic monomer.

Useful unsaturated anhydrides include maleic anhydride, citraconic anhydride, Itaconic anhydride and xconitsic anhydride.

The preferred comonomers are styrene and maleic anhydride.

The copolymers can also be rubber, such as butadiene rubber, polyisoprene rubber, rubbery copolymers of dienes with other comonomers such as styrene, crylonitrile, acrylic esters and the like including block copolymers of the A-B-A and AB type, wherein A is a vinyl aromatic compound such as styrene and B is a diene such as butadiene and which can be hydrogenated to bring the unsaturation to less than 10 tK reduce, as well as EPDII rubber.

The copolymers can be 50 to 5 Alol-t and more, preferably 1.5 to 85 mol%, of the alkenyl aromatic monomer and 5> is 50 mol- '¢, preferably 13 to 35 mol of the unsaturated anhydride. If there is a rubber, then this comprises 1 to 20% by weight of the polymer.

The rate of addition can easily be calculated by calculating the percentage of Total amount of unsaturated anhydride that is added per minute by one Reaction cycle of 2 to (3 hours to give) can be determined. In general the amount which is added per minute lies in the range between 0.3 × n and 0.7 g of the total amount of unsaturated anhydride to be added.

The temperature of the reaction can be in the range between 60 ° C and 100C and preferably in the range between 700C and 1100C, depending on the selection and the narrowness of the peroxide catalyst, the batch size and the shape of the reactor.

Ambient pressures are preferred, but prints of 1.1 to 10 atmospheres or more can be used.

It is desirable to have a peroxy catalyst in the invention Method to use. Useful peroxides include dibenzoyl peroxide, di-t-butyl peroxide, t-butyl hydroperoxide, dilauroyl peroxide, t-butyl peroxybenzoate, t-butyl peroxyoctoate 2,5-dimethyl-2,5-di- (benzoylperoxy) -hexane and the -1 fl nor the same. others useful Peroxides are / "Encyclopedia of Polymer Science & Technology, Volume <2, pages 814-839, Interscience publishers (196v8). The content of revelation this reference is incorporated in its entirety by this reference Registration recorded.

The peroxy compound can be used in small effective amounts, which depend on the particular peroxy compound selected. Generally lies the amount of the peroxy compound in the range from 0.01 to 1 wt. t, based on the total monomer and / or gum content of the reaction mixture.

The term "lower alkyl" used in the present application having 1 to 12 carbon atoms includes straight chain and branched chain hydrocarbon groups such as methyl, ethyl, isopropyl, n-butyl, n-octyl and the like. The designation lower alkenyl of 1 to 12 carbon atoms includes straight chain and branched chain ones Groups which have ethylenic unsaturation such as vinyl, n-propenyl, 2-BU-tenyl, 2-llexenyl and the like. The designation alkyl carboxylic acid groups with 1 to 12 Carbon atoms includes groups such as acetic acid, propanoic acid, n-butanoic acid, Decanoic acid group and the like. The designation 4lkenylcarboxylic acid groups with 1 to 12 carbon atoms includes groups such as propenoic acid, n-butenoic acid, n-octenoic acid groups and the same.

The following examples explain the process according to the invention. However, these examples are not intended to limit the scope of the invention in any way.

Example 1 In a 1.5 liter stainless steel resin kettle fitted with a three-neck cover and an addition funnel, a stirrer bearing and a reflux condenser had, 340 g of styrene monomer, 60 g of rubber and 300 g of methyl ethyl ketone were added. The mixture was stirred and heated in an oil bath at 60 C until the gum was complete was dissolved. Then the temperature of the bath to 85 to 90 ° C increased and a solution of 100 g of maleic anhydride and the desired amount of the benzoyl peroxide catalyst in 120 g of methyl ethyl ketone in the special addition rate admitted. When the addition was complete, the mixture was stirred for, before Start of the addition calculated, held at a temperature of 85-90 ° C. for 15 hours.

Then a solution of 6 g of di-t-butyl-pscresol antioxidant, dissolved in 50 g of methyl ethyl ketone, added and the mixture was for a further 2 stirred for up to 3 hours. The reaction mixture was then allowed to cool to 45 ° C and put in a large bowl. When most of the solvent has evaporated, the product was broken up and crushed (ground) to a granulated solid, which was further dried at 1200C under vacuum.

Styrene / maleic acid maleic anhydride benzoyl peroxide.

anhydride ratio addition time 1. 60/28 2 0.09 <V 2. 60/28 4 0.09 t 3. 60/28 8 0.09% 4. 60/28 12 0.09 «0 5. 68/20 2 0.11 t 6. 68/20 6 0.11% 7. 68/20 10 0.11 g 8. 68/20 15 0.11% 9. 68/20 2 0.15% 10. 68/20 3 0.15% 11. 68/20 4 0.15 % 12. 68/20 6 0.15% 13. 68/20 9 0.15 g 14. 68/20 15 0.15% 15. 68/20 2 0.20% 16. 68/20 5 0.20% Experiments 1 through 8 used Solprene 201, a solution polymerized Styrene butadiene rubber available from Phillips Petroleum Co., Bartlesville, Oklahoaa is available. the Experiments R to 16 used Solprene 1205, a styrene-butadiene-block copolymer, which contained 75 (in butadiene and which also available from Phillips Petroleum Co., Bartlesville, Oklahoma.

Example 2 Each of the copolymers prepared in Example 1 was used by (2.54 r \ a 1 inch / Wayne single screw extruder at 470-C melt temperature and the resulting strands were pelletized. Of any composition two batches were run in order to provide enough material for the shaping to have. The pellets were made into ASTM test pieces in an injection molding machine the further examination is shaped.

Izod impact resistant heat distortion heat distortion (3.2 mm test piece temperature (264 psi) temperature 2 Ft-Lb / inch of notch) OF (18.48 kg / cm) C 1.1 315 157 2.1.5 321 160 3. 1.1 310 154 4. 1.0 317 158 5. 1.7 269 131 6. 2.4 283 139 7.1.6 276 135 8.1.2 294 145 9.1.7 295 146 10.2.6 281 138 11.2.1 278 136 12. 1.4 263 128 13. 1.6 234 112 14. 1.0 248 120 15. 1.3 274 134 16. 1.0 273 133 All Test specimens were subject to a certain gel formation (crosslinking) during the molding process and the degree of gel formation had a direct influence on the heat distortion temperature, which was established. The heat distortion temperature also rose with the amount of maleic acid incorporated into the polymer.

Claims (7)

Claims. Process for the preparation of a copolymer from an alkenyl aromatic monomer of the formula: in which R1 CR1 - CHR2 R5> R4 $ 6 RR and R are selected from lower alkyl or lower alkenyl groups having 1 to 6 carbon atoms and hydrogen; R3 and R4 are selected from chlorine, bromine, hydrogen and lower alkyl with 1 to 6 carbon atoms, R5 and R6 are selected from the group consisting of lower alkyl and lower alkenyl groups with 1 to 6 carbon atoms or R5 and R6 via hydrocarbon groups with formation a naphthyl group are linked to each other; and an unsaturated anhydride of the formula wherein the dashed lines represent either a single or double carbon-carbon bond with the proviso that only one dashed line is a double bond and the other dashed line is always a single bond. R7 and fl together one -Group, R9 is selected from the group consisting of hydrogen, vinyl, alkyl with 1 to 12 carbon atoms, alkenyl with 1 to 12 carbon atoms, alkylcarboxylic acid groups with 1 I, is 12 carbon atoms, alkenyl carboxylic acid groups with 1 I> is 12 Carbon atoms, n is 1 or 2, depending on the position of the carbon-carbon double bond and m is an integer from 0 to 10, this process comprising the combination of the unsaturated Xn anhydride with the alkenyl aromatic monomer in a controlled addition rate, which extends over a period of 2 to 6 hours. 2. The method according to claim 1, d a d u r c h g e k e n nz e i c h n e t that the rubber is mixed with the alkenyl aromatic monomers, for which the unsaturated anhydride and a small effective amount of a peroxide catalyst is admitted. 3. The method of claim 1 or claim 2, d a d u r ch g e k It should be noted that the alkenyl aromatic monomer is styrene. 4. The method according to any one of the preceding claims d a d u r c h NOTICE that the unsaturated anhydride is selected from maleic anhydride, citraconic anhydride, itaconic anhydride and aconitic anhydride. 5. The method according to any one of the preceding claims d a d u r c h NOTICE that the unsaturated anhydride is maleic anhydride is. (3. The method according to any one of claims 2 to 5, d a -d u r c h g It is noted that the rubber is a styrene-butadiene rubber. 7. The method according to any one of claims 2 I> is (;, d a -d u r c Note that the peroxide catalyst is benzoyl peroxide.