EP0000419B1 - Procédé pour la préparation de copolymères et produits préparés ou partiellement préparés avec ces copolymères. - Google Patents

Procédé pour la préparation de copolymères et produits préparés ou partiellement préparés avec ces copolymères. Download PDF

Info

Publication number
EP0000419B1
EP0000419B1 EP78200094A EP78200094A EP0000419B1 EP 0000419 B1 EP0000419 B1 EP 0000419B1 EP 78200094 A EP78200094 A EP 78200094A EP 78200094 A EP78200094 A EP 78200094A EP 0000419 B1 EP0000419 B1 EP 0000419B1
Authority
EP
European Patent Office
Prior art keywords
polymerization
free radicals
added
weight
compound
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP78200094A
Other languages
German (de)
English (en)
Other versions
EP0000419A1 (fr
Inventor
Jozef Lambertus Maria Van Der Loos
Wilhelmus Gerardus Duijzings
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke DSM NV
Original Assignee
Stamicarbon BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Stamicarbon BV filed Critical Stamicarbon BV
Publication of EP0000419A1 publication Critical patent/EP0000419A1/fr
Application granted granted Critical
Publication of EP0000419B1 publication Critical patent/EP0000419B1/fr
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C08F2/16—Aqueous medium
    • C08F2/18—Suspension polymerisation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F279/00—Macromolecular compounds obtained by polymerising monomers on to polymers of monomers having two or more carbon-to-carbon double bonds as defined in group C08F36/00
    • C08F279/02—Macromolecular compounds obtained by polymerising monomers on to polymers of monomers having two or more carbon-to-carbon double bonds as defined in group C08F36/00 on to polymers of conjugated dienes
    • C08F279/04—Vinyl aromatic monomers and nitriles as the only monomers

Definitions

  • the invention relates to a process for preparing copolymers by polymerization in aqueous dispersion of 25-85 parts by weight of styrene and/or a-methyl styrene with 75-15 parts by weight of acrylonitrile and/or methacrylonitrile and, possibly, minor quantitites of one or more other monomers, optionally in the presence of a rubber, with the aid of one or more compounds yielding free radicals, in which process an additional amount of a compound yielding free radicals is added after the conversion has reached a value of more than 75 w.-%.
  • This quantity may even lie in the order of magnitude of a few per cent, depending on the polymerization conditions.
  • the monomer residues are highly undesirable. They have an adverse influence on the properties of the end product, such as gloss and heat resistance, and may moreover be released from the product during its subsequent processing or in its application, which is highly undesirable in view of the negative environmental impact and the toxicity.
  • the purpose of the invention is providing a process which yields polymers of a very low monomer content, without monomers of another kind having to be applied. Another purpose of the invention is providing a solution to the problem of removing non-converted monomer without negatively influencing the properties of the polymer. A further purpose of the invention is reducing the environmental impact and the possible risks from monomer emission during the production and processing of the polymer. It is also a purpose of the invention to raise the capacity of the polymerization reactors. Further, it is a purpose of the invention to utilize the monomers applied in a more efficient way.
  • the process for preparing copolymers according to the invention is characterized in that a compound which yields water-soluble free radicals which can be the same as, or different from the compound used at the beginning of the polymerization is additionally supplied in a quantity of 0.05-2.5 parts by weight per 100 parts by weight of total monomer after the conversion rate has become smaller than 15 w.% per hour, and the addition of monomers has been terminated, while at least 0.1 w.-% of non-converted (meth)acrylonitrile remains in the reaction medium.
  • the weight percentage of non-converted (meth)acrylonitrile is calculated with reference to the total reaction medium, i.e. water together with substances dissolved and dispersed in it.
  • the quantity of non-converted (meth)acrylonitrile in the reaction medium should be at least 0.1 w.-%. Preferably, this weight percentage should be at least 0.2 w.-% or, specifically, at least 0.5 w.-%. At lower values, no or hardly any reduction of the proportion of residual monomers occurs, especially as regards the proportion of styrene and a-methyl styrene. This is very surprising as styrene in particular is known to polymerize very easily.
  • the polymerization according to the invention takes place in an aqueous dispersion.
  • aqueous dispersion is understood to include both emulsions and suspensions.
  • the present invention is aimed in particular at the emulsion polymerization because in this polymerization the best results are obtained.
  • the extra monomers of which one or more may be included in the polymerization process in minor proportions are, among other, ionogenic vinyl compound and/or alkyl compounds, flame killers to be built in, or multi-functional compounds, such as di-vinyl benzene or an alkyl ester of (meth)acrylic acid. Special preference is given to polymers which contain more than 50 w.-% of styrene, in particular a-methyl styrene.
  • a-Methyl styrene monomer is very difficult to remove then. Particularly with these polymers the present invention appears to yield excellent results.
  • the emulsion polymerization can be carried out with a good result in the presence of a previously prepared rubber latex, for instance, a polybutadiene latex.
  • a graft polymer may form, which is of importance to the impact strength.
  • auxiliary materials necessary for that purpose should be applied, such as emulsifiers, lye, suspension agents, salts, soaps, initiators like peroxides, and molar-weight regulators.
  • emulsifiers emulsifiers
  • lye emulsion polymerization
  • suspension agents emulsifiers
  • salts emulsifiers
  • soaps emulsifiers
  • initiators like peroxides
  • molar-weight regulators emulsifiers
  • alkali-or ammonium-persalts and/or redox systems for initiators e.g. potassium persulphate, ammonium persulphate and sodium persulphate.
  • redox systems are persalts, (e.g. perchlorates or persulphates), tert.
  • butyl hydroperoxide cumene hydroperoxide, diisopropyl benzene hydroperoxide and methyl cyclohexyl hydroperoxide, combined with reduction agents based on acids containing sulphur in a low-valency state, such as sodium formaldehyde sulphoxylate, bisulphite, pyrosulphite, or with organic bases (like triethanolamine), with dextrose, sodium pyrophosphate and mercaptans or combinations thereof, optionally in combination with metal. salts such as ferrous sulphate.
  • acids containing sulphur in a low-valency state such as sodium formaldehyde sulphoxylate, bisulphite, pyrosulphite, or with organic bases (like triethanolamine), with dextrose, sodium pyrophosphate and mercaptans or combinations thereof, optionally in combination with metal. salts such as ferrous sulphate.
  • the polymerization in emulsion starts only slowly.
  • the conversion rate increases slowly, to reach a few hundred per cent per hour at the highest value. This means a considerable heat production within a relatively short time, which results in a temperature increase because the cooling cannot cope with this rapid heat development. Subsequently, the conversion rate will decrease slowly, whereupon according to the state of the art, the polymerization is discontinued at a point of time at which the polymerization rate has become too small for the polymerization still to be continued to advantage.
  • a polymer is obtained having such a low monomer content that the capacity problems occurring in the subsequent processing to, for instance, granulate, are eliminated straight away.
  • These capacity problems are the results of the measures to be taken to decrease the high monomer content, namely intensive and long drying and/or the application of degasifying extruders.
  • the compounds yielding water-soluble free radicals are, themselves, often completely water-soluble. Examples are persulphates, such as potassium persulphate and ammonium persulphate. But also compounds which are not completely water-soluble but yield water-soluble free radicals can be applied with very good results. Examples are the tert.-butyl-peroxy compounds, like di-tert. butyl peroxide, di-tert.
  • butylperoxydicarbonate tert. butyl peracetate, tert. butyl perpivalate, tert. butyl perbenzoate, and tert- butyl hydroperoxide.
  • These compounds are particularly preferable because very stable latices are obtained. This is of importance during transportation and storage of the latices. Further, also compounds which are not completely water-soluble and which form part of a redox system that yields water-soluble free radicals can be applied.
  • hydroperoxides such as cumene hydroperoxide, diisopropyl benzene hydroperoxide, triisopropyl benzene hydroperoxide, tert. butyl isopropyl benzene hydroperoxide and dodecyl isopropyl benzene hydroperoxide.
  • the amount of additionally added compound yielding free radicals preferably amounts to 25 to 500% by weight, particularly to 50 to 300%, by weight of the quantity of initiator added previously. Although in itself not necessary, it may offer advantages if the additionally supplied initiator consists of the same compound which was supplied at the beginning of the polymerization.
  • the additionally added compound yielding free radicals is preferably added after the conversion degree has become larger than 80%, by weight in particular larger than 90% by weight.
  • Conversion degree is understood to mean the quotient of the quantity of monomers converted into polymer and the total quantity of added monomers, multiplied by 100%. The addition does not take place until the conversion rate has become very low i.e. less than 15% by weight per hour, by preference lower than 8% by weight per hour, more particularly lower than 4% by weight per hour.
  • the temperature should be sufficiently high. Preference is given to temperatures above 30°C, preferably above 45°C. But the temperature should not be chosen too high. Suitable temperatures lie below 120°C, in particular below 100°C.
  • the half-life period of the compound yielding free radicals at these temperatures is, by preference, not too high, i.e. smaller than 5 hours, in particular smaller than 2 hours. It is advantageous to apply short half-life periods, which can be done by the choice of the temperature and/or the compound yielding free radicals. A half-life period smaller than 1 hour is the most preferable.
  • a redox initiator system was subsequently added to it which consisted of: 0.84 g of cumene hydroperoxide, 0.02 g of ferrous sulphate dissolved in 10 g of water, and the mixture of 1.0 g of sodium pyrophosphate in 1.2 g of dextrose dissolved in 30 g of water.
  • the temperature in the polymerization medium rose in 31 minutes to 86.5°C and dropped thereupon gradually to 75°C.
  • a sample of 1 ml was taken from the reaction medium after 90 minutes, counting from the point of time the initiator system was added, in which sample, after dilution with dimethyl formamide, the quantity of non-converted monomer was determined gas-chromatographically, from which the monomer conversion was calculated. This amounted to 94.9% at this point of time.
  • the polymerization rate can be determined by taking 2 samples in succession with a known, short time interval. This rate amounted to 1.2% per hour at this point of time.
  • Example I was repeated, 60 g of a polybutadiene rubber latex containing 50 w.-% of solid being added to increase the impact strength, whilst the total quantity of water of example I was kept constant.
  • example II was repeated, but without addition of tert. butyl perpivalate. This experiment was carried out in duplicate; the results thereof are given, between parentheses, in table 1.
  • the polymerization of acrylonitrile, styrene and a-methyl styrene was carried out in 2 steps, in which, according to the invention, extra potassium persulphate was added at the end of the second step.
  • the first step successively, the following were added to a polymerization vessel, while stirring: 230 g of water, 60 g of a 50% polybutadienelatex, 2 g of rosin soap, 0.14 g of KOH, 10 g of styrene, 26 g of acrylonitrile, 49 g of a-methyl styrene, and 0.2 g of tert. dodecyl mercaptan.
  • the initiator system was added, consisting of: 0.84 g of cumene hydroperoxide and 1.2 g of dextrose + 1.0 g of sodium pyrophosphate, dissolved together in 30 g of water, and 0.02 g of ferrous sulphate dissolved in 10 g of water. After 2 hours about 95% of the monomers had been converted into polymer.
  • Example III was repeated, without application however, of the extra potassium persulphate supply at the end of the second step. Comparison of the results of experiments III and Illa shows that in the process according to the invention a substantially improved monomer removal has taken place.
  • example I was repeated, a different initiator being added, however, in each example after 90 min.
  • examples IV and V forming part of the invention, considerably more monomer was converted into polymer during the last hour of the polymerization than in examples VI to X incl., in which a radical-yielding compound was applied which generates water-insoluble radicals.
  • table 3 For the results, reference is made to table 3.
  • composition of the monomer mixture was such that the concentration of the water-soluble component (acrylonitrile) under these polymerization conditions varied strongly at the time of adding the extra quantity of KPS.
  • the monomer mixture was such that the acrylonitrile concentration in the latex at the time of addition of the extra quantity of KPS was lower than 0.1%.
  • a ternary mixture of acrylonitrile, a-methyl styrene and methacrylate allyl ester in weight proportions of 31.9, 67.7 and 0.4, respectively, was polymerized in emulsion, as described in example I, with potassium persulphate as initiator.
  • potassium persulphate As initiator, One hour before termination of the polymerization, 0.8 g potassium persulphate dissolved in 10 g water was added.
  • the monomer concentration in the latex was 0.22% for ACN and 0.13% for a-methyl styrene, which means that the level of ⁇ -methyl styrene removal was very high.
  • Example XIV was repeated with a ternary mixture containing 20.4 parts by weight of acrylonitrile, 67.9 parts by weight of a-methyl styrene and 11.7 parts by weight of methyl methacrylate (MMA).
  • the MMA was not initially present, but was gradually supplied to the reactor in about 40 minutes subsequent to addition of the initiator; 30% of the required quantity of ACN was supplied to the reactor only after 190 minutes.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Polymerisation Methods In General (AREA)
  • Graft Or Block Polymers (AREA)

Claims (4)

1. Procédé de préparation de copolymères par polymérisation, dans une dispersion aqueuse de 25-85 parties en poids de styrène et/ou d'a-méthylstyrène avec 75-15 parties en poids d'acrylonitrile et/ou de méthacrylonitrile et, éventuellement, une faible portion d'un ou de plusieurs autres monomères, éventuellement en présence d'un caoutchouc, à l'aide d'un ou de plusieurs composés produisant des radicaux libres, procédé dans lequel on ajoute une quantité supplémentaire d'un composé produisant des radicaux libres après que le degré de conversion a atteint une valeur de plus de 75% en poids, caractérisé en ce qu'un composé produisant des radicaux libres solubles dans l'eau, qui peut être le même ou différent de celui utilisé au début de la polymérisation, est ajouté additionnellement par une quantité de 0,05-2,5 parties en poids par 100 parties en poids du monomère total, après que la vitesse de conversion est devenue inférieure à 15% en poids par heure, et après que l'addition de monomères est terminée et que du moins 0,1% en poids de (méth)acrylonitrile non converti, calculé par rapport au médium réactionnel total, reste dans le médium réactionnel.
2. Procédé selon la revendication 1, caractérisé en ce que le composé produisant des radicaux libres soluble dans l'eau est ajouté quand du moins, 0,2% en poids de (méth)acrylonitrile non converti reste dans le médium réactionnel.
3. Procédé selon l'une des revendications 1 à 2, caractérisé en ce que le composé produisant des radicaux libres solubles dans l'eau est choisi parmi le groupe consistant de composés tert.-butyl-peroxy, hydroperoxydes et persulfates.
4. Produits consistant entièrement ou partiellement du copolymère préparé selon l'une ou l'autre des revendications 1 à 3.
EP78200094A 1977-07-19 1978-07-13 Procédé pour la préparation de copolymères et produits préparés ou partiellement préparés avec ces copolymères. Expired EP0000419B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL7708002A NL7708002A (nl) 1977-07-19 1977-07-19 Werkwijze voor het bereiden van vinylpolymeren.
NL7708002 1977-07-19

Publications (2)

Publication Number Publication Date
EP0000419A1 EP0000419A1 (fr) 1979-01-24
EP0000419B1 true EP0000419B1 (fr) 1981-11-25

Family

ID=19828908

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78200094A Expired EP0000419B1 (fr) 1977-07-19 1978-07-13 Procédé pour la préparation de copolymères et produits préparés ou partiellement préparés avec ces copolymères.

Country Status (6)

Country Link
US (1) US4200593A (fr)
EP (1) EP0000419B1 (fr)
JP (1) JPS5421490A (fr)
DE (1) DE2861350D1 (fr)
IT (1) IT1107794B (fr)
NL (1) NL7708002A (fr)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3170382D1 (en) * 1980-06-05 1985-06-13 Sumitomo Naugatuck Process for preparing copolymers
DE3169657D1 (en) * 1980-07-01 1985-05-09 Stamicarbon Process for the preparation of a copolymer
IT1198338B (it) * 1980-07-02 1988-12-21 Montedison Spa Processo per produrre copolimeri di monomeri vinil-aromatici con nitrili etilenicamente insaturi
JPS5882042A (ja) * 1981-11-10 1983-05-17 Mazda Motor Corp エンジン始動時の空燃比制御装置
NL8303241A (nl) * 1982-09-24 1984-04-16 Cosden Technology Werkwijze en inrichting voor de bereiding van styreen/alkenylnitrile copolymeren.
JPS5962604A (ja) * 1982-10-01 1984-04-10 Kanegafuchi Chem Ind Co Ltd 共重合体の製造方法
EP0157314A1 (fr) * 1984-03-29 1985-10-09 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Procédé de préparation de copolymères
IT1190360B (it) * 1985-05-24 1988-02-16 Enichem Polimeri Processo per la preparazione di polibutadiene aggraffato con stirolo ed acrilonitrile avente bassissimo contenuto finale di monomeri residui non reagiti
JPH0276165U (fr) * 1988-11-30 1990-06-11
US5444141A (en) * 1994-07-06 1995-08-22 Arco Chemical Technology, L.P. Process for making vinyl aromatic/allylic alcohol copolymers
DE10049466A1 (de) * 2000-10-06 2002-04-11 Bayer Ag Verfahren zur Herstellung von Pfropfkautschuklatices mit reduziertem Restmonomerengehalt
PL2054472T3 (pl) 2006-08-18 2015-11-30 Styrolution Europe Gmbh Termoplastyczne tłoczywa na bazie akrylonitrylu, styrenu i butadienu, oraz środek aglomerujący zawierający akrylan etylu i metakryloamid
WO2013104527A1 (fr) 2012-01-13 2013-07-18 Styrolution GmbH Matières de moulage terpolymères à faible indice de jaune, procédé pour les produire et leur utilisation
KR101957666B1 (ko) * 2015-12-04 2019-03-13 주식회사 엘지화학 내열 san 수지의 제조방법

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2665271A (en) * 1951-10-25 1954-01-05 Gen Aniline & Film Corp Polymerization of n-vinyl lactams
US3010936A (en) * 1958-08-07 1961-11-28 Borg Warner Blend of graft copolymer of polybutadiene, styrene and acrylonitrile with interpolymer of alpha methyl styrene and acrylonitrile
US3053800A (en) * 1959-05-04 1962-09-11 Borg Warner Blends of (1) polyvinylchloride, (2) a copolymer of polybutadiene, styrene and acrylonitrile and (3) a copolymer of acrylonitrile, styrene and alpha methyl styrene
US3414547A (en) * 1963-06-13 1968-12-03 Nalco Chemical Co Polymerization process
DE1745360C3 (de) * 1968-01-27 1974-11-21 Reichhold-Albert-Chemie Ag, 2000 Hamburg Verfahren zur Herstellung von geruchsarmen Dispersionen
US3534009A (en) * 1969-01-29 1970-10-13 Du Pont Method for reducing residual vinyl acetate monomer
DE2354681C3 (de) * 1973-11-02 1979-08-23 Hoechst Ag, 6000 Frankfurt Verfahren zur Herstellung wäßriger Copolymerdispersionen

Also Published As

Publication number Publication date
IT7850357A0 (it) 1978-07-18
EP0000419A1 (fr) 1979-01-24
IT1107794B (it) 1985-11-25
US4200593A (en) 1980-04-29
NL7708002A (nl) 1979-01-23
JPS5421490A (en) 1979-02-17
DE2861350D1 (en) 1982-01-28
JPS6236044B2 (fr) 1987-08-05

Similar Documents

Publication Publication Date Title
EP0000419B1 (fr) Procédé pour la préparation de copolymères et produits préparés ou partiellement préparés avec ces copolymères.
JP3549902B2 (ja) グラフト共重合体およびその製造方法
US3498942A (en) Emulsion polymerization of unsaturated monomers utilizing alkyl sulfide terminated oligomers as emulsifiers and resulting product
US6444760B1 (en) Method of reducing the content of residual monomers in aqueous polymer dispersions
US2289540A (en) Polymerization of water soluble polymers
US5721310A (en) Low VOC emulsion
US5399621A (en) Process for the preparation of a graft copolymer latex of core/shell dispersion particles having improved phase binding between core and shell
DE1595680A1 (de) Sulfonsaeuregruppen enthaltende Polymerisate
KR970703373A (ko) 중합체 수분산액의 제조 방법(Method of Producing an Aqueous Polymer Dispersion)
US4272425A (en) Treating dispersions of acrylonitrile polymers
KR100345911B1 (ko) 아크릴적중합체들의제조방법
EP0186926B1 (fr) Méthode de préparation de copolymères greffés par polymérisation en émulsion
US3321431A (en) Aqueous resin emulsions
US4129703A (en) Free-radical polymerizations using mixed initiator systems at two thermally distinct polymerization stages
US3222328A (en) Process for polymerizing vinyl monomers with a catalyst of peracetic acid and an alkyl mercaptan
EP0071116B1 (fr) Polymérisation en suspension avec addition d'un solvent
EP0206378B1 (fr) Procédé de préparation de polybutadiène greffé par du styrène et de l'acrylonitrile et contenant un taux final très faible de monomères libres
US3523111A (en) Emulsion polymerization of vinyl chloride with redox initiator system components and emulsifier prepared before monomer addition
EP0007044B1 (fr) Procédé de préparation de latex de caoutchouc exempts de matons et présentant une tension superficielle élevée
US4404338A (en) Process for preparing copolymers of vinyl-aromatic monomers with ethylenically unsaturated nitriles having low content of unreacted residual monomers
DE2840502A1 (de) Verfahren zur herstellung von terpolymeren
US2404817A (en) Production of copolymers of monoethenoid compounds
JPS6261048B2 (fr)
US3956163A (en) Pigmented detergents
GB1497602A (en) Process for producing an impact resistant thermoplastic graft copolymer

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): BE DE FR GB NL

17P Request for examination filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): BE DE FR GB NL

REF Corresponds to:

Ref document number: 2861350

Country of ref document: DE

Date of ref document: 19820128

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19920625

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19920629

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19920706

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19920731

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19920903

Year of fee payment: 15

NLS Nl: assignments of ep-patents

Owner name: DSM N.V. TE HEERLEN.

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19930713

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Effective date: 19930731

BERE Be: lapsed

Owner name: STAMICARBON B.V.

Effective date: 19930731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19940201

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19930713

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19940331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19940401

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT