CA2093289A1 - Process for imparting wet strength to paper - Google Patents

Process for imparting wet strength to paper

Info

Publication number
CA2093289A1
CA2093289A1 CA002093289A CA2093289A CA2093289A1 CA 2093289 A1 CA2093289 A1 CA 2093289A1 CA 002093289 A CA002093289 A CA 002093289A CA 2093289 A CA2093289 A CA 2093289A CA 2093289 A1 CA2093289 A1 CA 2093289A1
Authority
CA
Canada
Prior art keywords
paper
polyisocyanates
water
dispersible
polyisocyanate
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.)
Abandoned
Application number
CA002093289A
Other languages
French (fr)
Inventor
Harro Traeubel
Hans-Josef Laas
Helmut Reiff
Joachim Konig
Jurgen Reiners
Harald Faika
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.)
Bayer AG
Original Assignee
Individual
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Filing date
Publication date
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Application filed by Individual filed Critical Individual
Publication of CA2093289A1 publication Critical patent/CA2093289A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • D21H21/18Reinforcing agents
    • D21H21/20Wet strength agents
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00Polymeric products of isocyanates or isothiocyanates
    • C08G18/06Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08Processes
    • C08G18/10Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00Polymeric products of isocyanates or isothiocyanates
    • C08G18/06Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/703Isocyanates or isothiocyanates transformed in a latent form by physical means
    • C08G18/705Dispersions of isocyanates or isothiocyanates in a liquid medium
    • C08G18/706Dispersions of isocyanates or isothiocyanates in a liquid medium the liquid medium being water
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/03Non-macromolecular organic compounds
    • D21H17/05Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
    • D21H17/07Nitrogen-containing compounds
    • D21H17/08Isocyanates
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • D21H21/18Reinforcing agents
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20Macromolecular organic compounds
    • D21H17/33Synthetic macromolecular compounds
    • D21H17/46Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/54Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
    • D21H17/57Polyureas; Polyurethanes

Abstract

Process for imparting wet strength to paper Abstract of the Disclosure The novel AOX-free process for imparting wet strength to paper with water dispersible polyisocyanates is distinguished by a good wet-strength effect, even under mild drying conditions, and does not affect the activity of optical brighteners used at the same time.

Description

2~932~9 It has been known for a long tim~ to use reaction product~ of polyamidoamine~ and/or polyamines with ~pichlorohydrin for Lmpro~ing the wet strength of paper.

H~weve~ thase known wet-~trength agents contain a c~rtain amount of organically bonded chlorine.

The organic ~hlorine content is made up partly of chloro-hydrin group8 and partly of chlorin~ originating fro~
low~molecular ~econdary components formed from epichloro-hydrin during the ~ynthe~

For application as a wet-strength agent, an aqueou~
: solution of the polycondensation product i6 added to a pulp slurry, from which the sheet of paper is formed by d~watering. A certain proport.ion of organic halogen compounds thereby passes into ~he effluent from paper manufacture, where it can be determined a~ the ~o- called AOX value (DIN 38 409part 14).

It is known that th~ tensile strength (dry and wet) of paper, cardboard etcO can be Lmproved by the addition of a basic polyurethane ~cf. German patPnt application A-3 1~2 038).

Processes for imparting we~ strength to paper are also known in which prepol~mers derived from polyisocyanates having NCO groups of different reactivity ~e.g. from TDI) Le A 28 857 .

2~32~

are applied to the dry paper from solution in the pre~ence of catalys~s (cf. e.g. US patent specification 3 702 781~.

~ queous dispersions of isocyanate prepolymers in which the isocyanate groups are blocked have also b~en proposed for the impregnation of paper in order to increase i~5 dry and wet streng~h (cf. European patent application A-17 598).

~ he impregnation of paper, for the purpose of Lmparting wet and dry ~trength, with mixtures of polyalcohol t isocyanate and polyamine, which are capable of curing in the paper, has al~o been described (cf. German patent application A~2 264 699).

Used in the stock, cationic polymers containing isocyanate and pr.unaxy amine groups, which can be obtained by the Hoffmann degradation of copol~mers of (meth)acrylamide etc., are al80 suitable, after heat treatment, for ~trengthening pa]per (cf. Japanese patent specification 57 149).

Thus, on the one hand, the state of the art is the tre~tment of paper with capped isocyanates or other reactive mixtures which are capable of being con~erted to polyurethane in the sub~trate; on ~he other hand, melaminP~formaldehyde or urea/formaldehyde condensation product~, or polyamidoamine/epichlorohydrin resins, are used for this purpose (~llmann Encyklopadie der L~ A 28 857 - 2 -2~32~

technischen Chemio [Ull~ann's ~ncyclopaedia of Ch~ical 'rechnology), ~einheLm, ~o1. 1~, 1979~, page 585).

Conventiona11y ~ynthesised wet-~trength ~gents are o~ten qusternis~d poly~id~, polyLmides etc. Tho cationic structur~ of the~e products i~ ~upposed to be r~spsnsible for their absoxption ~y the cellulo~e fibres (R. Pel~er et al., Wochenblatt fur P~pierf~brikation Weekly Journal for P~per ~nuf~cture, 11/12 (1989~ p. 499).

However, these processes, known from the state of the art, for imparting wet or dry strength to paper are not satisfactory in all requirements, in particular with regard to the organic halogen content (OX content~ of the products employed and the resulting AOX ~= adsorbed organic halogen) pollution of effluents from paper mills.

The problem therefore existed of providing a new process for imparting wet stxength to paper and paper-like materials, in which a halogen-free wet-strength agent based on water-dispersible polyisocyanates is used which has the same wet-strength effect as conventional wet-strength agents based on polyamidoamine/epichlorohydrin resin in stock and surface treatment over a wide pH range and also increases dry strength.

It has now surprisingly been found that water-dispersible polyisocyanates are excellently suitable a~ dry- and wet-strength agents for paper. They can be added prior to sheet formation tStock application), i.e. as additives to the fibre stock suspension, or to the paper surface, i.e. by being applied to a formed sheet of paper.

Le A 28 857 - 3 -. '",' ~':

: .:
., . ~ .

2~32~

~he present invention thus relates to a process for ~he production of paper and paper-like materials having dry and wet st~ength, characterised in that the paper or paper-like material or the pulp used for the production of the paper or the paper-like material is treated with water-dispersible polyisocyanates.
.~.
Mi~tures of non-autodispersible polyisocyanates with external, ionic or non-ionic emulsifiers can also be used a~ w~ter-dispersible polyisocyana~es.

However, a preferred embodiment of the process according to the invention u~es autodispersible polyisocyanates such as, for example:

(I) water-dispersible non-ionic polyisocyanate mixtures of polyisocy2nates and polyisocyanates modified ~y ~ .
polyethers and conta.iniDg cycloaliphatically and/or : Le A 28 857 - 4 -~' . .. .. ~

,:
', ~, ~93~9 aliphatically bonded isocyanate groups, (II~ polyisocyanate mixtures of polyisocyanates and polyisocyanate~ modified by carboxylate group~ and containing cycloaliphatically and/or aliphatically bonded isocyanate groups, or (III) water-dispersible non-ionic polyisocyanates containing aromatically bonded isocyanate groups, or mixtures of such polyi~ocyanates.

It is preferable to u~e water-dispersible polyizocyanate mixtuxe~ (I) with a ) a mean NC0 functionality of 1. 8 to 4 . 2, b) a content of alipha~ically and/or cycloaliphatically bonded isocyanate groups (calculated as ~C0, mole-cular weight - 42) of 12.0 to 21.5~ by weight, based on ~he polyisocyanat~ mixtu:re (I), and c) a content of ethylene oxid~s units situated within polyether chains ( calculated as C;~H40, molecular weight = 44 ) of 2 to 209~ by weight, based on the polyisocyanate mixture ( I ), the polyether chains having a statistîcal mean of 5 to 70 ethylene oxide units.

The water-dispersible polyisocyanate mixtures (I) can be prepared in a manner known per se by reacting a Le A 28 857 - 5 -.. . . . .

' ~93~

polyi~ocyanate component A) with a (mean) ~CO
functionality of 2.1 to 4.4, preferably 2.3 to 4.3, con~l~ting of at lea~t one polyisocyan~te containing exclu~ively aliphatically and/or cycloaliphatically 5 bonded isocyanate groups, with a monohydric or polyhydric polyalkylene oxide polyether-alcohol B) having ~ta~i3tic81 mean of 5.0 to 70 ethylene oxide unit~, while maintaining an NCO/OH equivalent ratio of at least 2:1, generally of 4.1 to approx. 1000:1, the type and proportions o~ said starting components moreover being cho~en so that the re~ulting reaction products satisfy the conditions mentioned above under a) to c).

The polyisocyanate components A) may have a ure~dione and/
or isocyanurate, urethane and/or allophanate, biuret or oxadiazine structure, such as those described for example in German patent application A-l 670 666, German patent application A-3 700 209 and Germ,an patent application A- :
3 900 053 or in European patent application A-336 205 and European patent application A-339 396, which can be prepared by modifying sLmple aliphatic and/or cycloaliphatic diisocyanates.

In principle, suitable diisocyanates for the preparation of such polyisocyanate compone~ts ~ are ~hose whose molecular weight is in the range from 140 to 400 and which contain aliphatically and/or cycloaliphatically bonded i~ocyanate groups ~ such as e~g. 1,4-diisocyanato-butane, 1,6~diisocyanatohexane/ 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl l,6-di-Le A 28 857 - 6 ~

2~32~

i~ocyanatohaxane, l,lO~diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5~isQcyanatomethylcyclohexane (i~ophorone dii~ocyanate) and 4,4'-diisocyanatodicyclohexylmethane or ~:
any desired mixtures of ~uch dii~ocyanate~. In general, it would al~o be po~sible to use aromatic isocyanate~
such a~ e.g. toluylene dii~ocyanate and 4,4'-diisocyanato-diphenylmethane; because the latter lack light fastne~ and are exces8ively reactive towards water, however, the aliphatic isocyanates are preferred, although mixed trLmers of aliphatic and aromatic diisocyanates have a certain intere~t.

The starting components A) used for the preparation of the water-disper~ib~.e polyisocyanate mixtures are preferably polyisocyanate mixtures with an NC0 content of 19 to 24~ by weight, based on component A), which have isocyanurate groups consisting essentially of trLmeric 1,6-diisocyanatohexane an~or dLmeric 1,6-di-isocyanatohexane, and/or uretdione and/or biuret groups. The corresponding polyisocyanates wi~h said NC0 content which are substantially free of uretdione groups and have isocyanurate or biuret groups, such as those obtained by the catalytic ~rimerisation, known per se, of 1, 6-di-isocyanatohexane and preferabl~y having a (mean) NC0 ~5 functionality of 2.2 to 4.2~ are particularly preferably used a~ component A). Instead of the trimers, it is also ~-possible to use biurets (ob~ained in known manner by : specif ic reaction with water) or oligourethanes ~uch as those formed e.g. by reacting the diisocyanates with Le A 28 85? ~ 7 ~ :

,' .~ ' ,~ ' ~ ' -.
.
.

.

, .

~32g9 trlmethylolpropane/ pentaerythritol or sorbitol.

The component B) con~ist~ of monohydrlc or polyhydric polyalkylene oxide polyether-alcohols having a statistical mean of 5 to 70, preferably 6 to 60 ethylene oxide units per molecule, such as those obtainable in a manner known per se by the al~oxylation of suitable starter molecules.

Any desired monohydric or polyhydric alcohols whose molecular weight i~ in the ran~e from 32 to 150, such as those also used, for example, according to European patent applicati~n A-206 09, can be used a~ starter molecules for the preparation of the polyether-alcohols B). Monofunctional aliphatic alcohols having 1 to 4 carbon atoms are preferably used as starter molecules. It is particularly preferable to use methanol.

Alkylene oxides suitable or the alko~ylation reaction are especially ethylene oxide and propylene oxide, which can be used in the alkoxylation reaction in any desired order or else in a mixture.

The polyalkylene oxide polyether-alcohols B) are either pure polyethylene oxide polyether~ or mixed polyalkylene oxide polyethers containing in each case at least one polyether chain which has at least 5, generally 5 to 70, preferakly 6 to 60 and particularly preferably 7 to 20 ethylene oxide units and in which at least 60 mol~, preferably at least 70 mol~ of the alkylene oxide units Le A 28 857 -8 -2~32~

con~ist of ethylene oxide unit~.

Preferred polyether-alcohols B) for the pr~paration of the water-dispersible polyisocyanate mixtures (I) axe mono~unctional polyalkylene oxide polyather~ which have been started on an aliphatic alcohol ha~ing 1 to 4 carbon atoms and which contain a statistical mean of 6 to 60 ethylene oxide units. Particularly preerred polyether-alcohols B) are pure polyethylene glycol monomethyl e~her-alcohol~ having a ~tatistical mean of 7 to 20 ethylene oxide units.

The polyisocyanate mixtures (II) which are preferably used are polyisocyanate mixtures containing carboxyl group~, ~uch as those described in German patent application A-4 001 783, which can readily be dispersed in water af~er at least partial neutralisation of the carboxyl groups.

As water-dispersible non-ionic polyisocyanates containing aro~atically bonded isocyanate groups (III~, it i5 preferable ~o use tho~e described e.g. in Bri~ish patent ~0 application A-1 444 933 and British patent application : A-2 018 796, European patent application A- 61 628 or German patent application A-2 '103 271. Said substances can be used in any desired mixture with one another.

As non-autodispersible polyisocyanates, it is preferable to use polyisocyanate components A~ in a mixture with external ionic or non-ionic emulsifiers. Such emulsifiers Le A 28 857 - 9 , , ~ ~ - :
: . - ~

-'' ' ' ::
.
: ' 2~932~

are described for example in Methoden der organischen Chemie tMethod~ of Organic Chemi~txy), Houben~Weyl, vol.
XIV/l, part 1, pages 190-208, Georg- Thieme-Verlag, 5t~tgart 1961, or ln US pat~nt specification 3 428 592 or European patent applicatlon A- 13 112. The emulsifiexs ar2 used in an amount which ensur~s dispersibility.

To facili~a~e incorpora~ion into thP aqueous phase, the wa~er-dispersible polyisocyanates used in the process . according to the invention can optionally be used dis~olved in a ~olv~nt inert towards i~ocyanate groups.
Examples of ~uit~ble solvents are ethyl ac~tat~, butyl ace~ate, ~hylene glycol monomethyl or monoethyl ether-acetate, 1-methoxyprop-2-yl acetate, butan-2-one, 4-methylpentan-2-one, cyclohexanone, toluene or mi~ture~
thereof, or else solvents such as propylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol ethyl and butyl ether-acetate, N-methylpyrrolidone and N-methylcaprolactam, or mixtures of such sol~ents.
These solvents are optionally added to the water-dispersible polyisocyanates in amounts of up to 90~ byweight, preferably at most 50~ by weight and par~icularly preferably at most 20~ by weight, based on the solu~ion formed. However, it .is very particularly preferable ~o use solvent-free water-dispersi,ble polyisocyanates.

In the process according to the invention, the water-di~per~ible polyisocyanate~ are u6ed in amount~ of O.005 to 50% by weight, preferably 0.1 to 10~ by weight, based on the paper ~tocX,o they are preferably used in the L~ A 28 857 - lO-2 ~ 9 ~tock, i.e. they are added directly to the wood fibro/cellul~se fibr2 dispersion. Before the polyisocyanatas axe used, e~pecially when added to the paper pulp, they can be predisper~ed with 1-4 tLm~8 thQ
S amount of water, ba~ed on polyisocyanate. The use of the component (I) thereby permits processing tLmes of up to 24 hours. When water dispersible aromatic polyisoc~anates (III~ are used, the proce~sing tLmes are markedly shoxte~, because of the higher reacti~ity toward~ water, and are generally up to a hours.

The water dispersible polyisocyanates to be used according to the invention can b~ employed at the processing temperatures con~entionally used in the paper industry~ whereby the processing tLmes for the products to be used according to the invention can vary according to temperature. Thus, for example, the proc0ssing times for the polyisocyanate of Example A) at 23-25C are relatively long since approx. 60% of isocyanate groups are still present. after 5 hours at this temperature. With : 20 polyisocyanate A), approx. 50% of isocyanate groups are still present after 5 hours at a temperature of 35C and 33~ are still present af~er 3 ]hours at 50C. Thus the processing time at a particu]ar temperature can be influenced by choosing a suitable polyisocyanate to be used according to the invention.

The water-dispersible polyisocyanates to be used according to the invention are sui~able both for surface treatment and for stock addition. The products to be Le A 28 857 ~ ll ~

.. . . .
'' , -' 2 ~

used according to the invention can al~o be employed in the ~izing pre~, making it possible to manuf~cture paper~ resistant ~o wa~er, oll ~nd benzine.

The pH of the cellulose stock or the paper should preferably ~e between 5 and 8.5, especially in the region of neutrality, when the products to be used according to the invention are add d. pH value~ below 4 or above 9 should be avoided.

Th~ products to be used according to the in~ention make it pos~ible to Lmpart wet ~trength to paper without pollutiny the effluent with organic halogen compounds (determined as the AOX value according to DIN 38 409Part 14).
As can be se n from the Examples, it is also possible to improve the wet tear strength, even under mild drying conditions, directly in th~ machine, i.e. the customary appreciable condensation or maturing times of the products are no longer necessary. Furthermore, the products are distinguished in that they do not inhibit : the activity of normalq~iOE~ ~n~ conventionally used in paper manufacture.

: The products can optionally al~o be used together with conventional cationic fi~ing agent~ and retention agents, - preferably with wet-stre~gth agents. In terms of the in~ention, retention a~ents are cationic polycondensation products of polyamines, pr~ferably N- methyl-bis(3-~minopropyl)amine, with alkylene dihalides, preferably dichlorQethane. Particularly preferred retention agents Le A 28 857 - 12 -2~32~

are tho~e which have no free ~l- or -NH2 groups.

~hen the products to be used according to the invontion are employed together with convcntional wet-strength agent~, it is possible in particular to lower the AOX
pollution of the ~ffluent caused by the~e conventional wet-~treilgth agents. Furthermore, in most ca~es, the wet-~trength effect is synergistically enhanced and the retention of pigment6 r fillers etc. Lmproved.

The water-di~perYible polyi~ocyanates to be used according to tho invention can be employed in a mixture with 0~005 to 50 parts by weight, preferably 0.1 to 10 parts by weight of a retention agent based on a cationic polycondensation product of polyamines and alkylene dihalides, the amount of ret~ntion agent being ba~ed on lS the paper stock.

The water~dispersible polyisocyana~es to be used according to the invention can be employed in a mixture with 1 to 400 parts by weight, preferably 10 to lQ0 parts by weight of a polyamidoamine/epichlorohydrin resin, based on the polyisocyanate.

The products which are preferably used as polyamidoamine/epichlorohydrin resins are those prepared by the reaction of ~:
( ~ ) polyamines containing at least three amino groups per molecule, and ( ~ ) C3-C,O-dicarboxylic acids, ;, ".

.

Le A 28 857 - 13 ~

:~,..... .

~ . , :

2 ~

the molar ratio of (u) to (~) being 1:0.8 to 1.1.4, and ~ub~equent reaction of the resulting polyamidoamine with epichlorohydrin, 1.0 to 1.8 mol of epichlorohydrin being u~ed per mol of basic amino group~ in the polyamidoamine (g).

As dicarboxylic acids (~), it i~ preferable to use saturated aliphatic dibasic carboxylic acids having 3 to 10 C atoms, su~h as e.g. malonic acid, succinic acid, adipic acid or azelaic acid, or mixtuxes of the~e acids.

As polyamines (~), it is possible ~o use a mul~itude of polyalkylenepolyamines, including polyethyl~ne-polyamin~s, polypropylenepolyamines and polybutylene-polyamines. In the polyalkylenepolyamines, the al~ylene groups have more than 1 C atom and there are two to eight 1~ such groups in the molecule. The nitrogen atoms can be bonded to adjacent carbon atoms in the group CnH~- or to more remote carbon atoms, but not to the same carbon atom. It is possible not only to use polyamines such as diethylenetriamine, triethylenetetramine, tetraethylene-pentamine, dipropylenetriamine and N-bis-(aminopropyl)-methylamine on their own, but also to use mixtures of these and their crude products. For example, ~he mix~ure of polyethylenepolyamines obtained by reaction of ammonia : and ethylene dichloride and purification only to the extent of removing chlorides, water, excess ammonia and ethylenediamine is a very satisfacto~y starting material.
Product~ prepared from a di~tillation re~idus from ~he refining of the low polyethylenepolyamines, and Le A 28_857 -14 '' , ~ .

2~32~

con8ist ing essentially of polyamines higher than tetraethylenapentamine, can also be used.

Of course, it i~ al80 pO8 ibls to u8e compounds which contain smaller group~ bondsd to nitrogen, ~uch as CH2CH2OH, and ~hich are almo~t alway~ pre~0nt to a certain extent in commercially available polyamines as the result of a secondary reaction in the conventional proces~es by which polyalkylenepolyamines are pr~pared. Oxyalkyl-sub~tituted polyamine~ can also be used.

The process ~or the preparation of the~e polyamidoamine/-epichlorohydrin resins i8 described in Genman Auslegeschrift 1 177 824.

Examples A D de~cribe the preparation of the polyisocyanates and Example~ 1-5 describe th~ir use.

Examples _olyisocyanate A

0.08 val of a monofunctional polyethylene oxide polyether started on methanol, with an average molecular weight of 350, is added at room temperature, with stirring, to 1.0 val of a polyisocyanate containing isocyanurate groups and based on 1,6-diisocyanatohexane (HDI), with an NCO
conten~ of 21.5% and a viscosity of 3000 mPas (23~C), and the mixture is then heated for 3 h at 100C. A prac-tically colourless, clear polyisocyanate mixture Le A 28 857 - 15 _ 2~32~

according to the invention i8 obtained after cooling to room temperature. The NCO content i~ 17.3% ~nd the visco~ity i~ 3050 ~Pa~ (23JC).

8 parts of the polyisocyanate obtained in this way are 5 diluted with 2 parts of propylene glycol diacetate to give an 80~ solution with an NCO content of 12.6~ and a visco~ity of 510 mPas.

Poly~isocyanate B

0.013 val of a monofunctional polyethylene oxide poly-ether started on 3-ethyl-3~hydroxymethyloxetane, with an av~rage molecular weight of 1210, is add2d at room temperature, with stirring, to l.0 val of the polyiso-cyanate used for the preparation of polyisocyanate A, containing isocyanurate groups and based on 1,6-diiso-cyanatohexane, and the mixture i~ then heated for 2 h at100C. A practically colourles~;, clear polyisocyanate mixture according to the invention is obtained after cooling to room temperature. The N~O content is 19.6% and the viscosity is 2900 mPas (23C).

PolYisocyanate C

d~01 val of a monofunctional polyethylenP oxide/
pol~propylene oxide polyether started on n-butanol, with a content of ethylene oxide units of 80% and an average molecular weight of 2150, is added at room temperature to 1.0 val of the polyiso~yanate used for the preparation of Le A 28 857 16 ~

2~932~

polyisocyanate A, eontaining isocyanurate groups and based on 1,6-diisocyanatohexane, ~nd thP mixture is than heated for 1 h at 100C. A pale yellow, clear polyi~ocyanate mixture with an NCO content of 17.8~ and a vi8c05ity o 3360 m~as (23C~ i~ obtained after cooling to room t~mperature.

Polyisocyanate D

A semiprepolyme~ i8 prepared at 95C, over 1.25 hoursO
from 300 g of a trifunction~l EO/PO poly~ther ba~ed on trimethylolpropane; with a molecular weight of 4800 (EO/PO = lS/85), 120 g of an EO/PO polyether started on n-butanol, with a molecular weight of 2150 (EO/PO =
80/20), and 80 g of isophorone diisocyanate.

The mixture is catalysed with 1 drop of tin octoate, kept at 90C for 30 minutes and then dis~olved in 125 g of methoxypropyl acetate~ The clear solution ha~ an NCO
; content of 4.Q% (ba~ed on solids).
:
66 g of this product are diluted with a further 145 g of methoxypropyl acetate, 107 g of polyisocyanate ~ are added and the mixture is stirred for 30 minutes at room.
temperature to give a clear, pa:Le yellow resin solution : with an NCO content of 7.4~. The solids content is 50%.
The NCO cont~nt based on solids is 14.8~.

Le A 28 857 ~ 17 ~

.

, .

2 ~ ~ :

~ ~3oe~

2%, 4% and 8~ dispersions of polyisocyanate A (80%
active compound in propylene glycol diacetate) in water were prepared as the sizing preqs liquor and used for treating mechanical paper (containing about 35% of groundwood pulp; 80g/m2) in a sizing press with 100~ liquid uptake.
The breaking ~train of the paper obtained (dry ~nd wet) was ac follow~;

Sizing press Acti~e Breaking Bre~king liquor substan~strain strain concentration dry wet [X] lN~ IN]

OZ of polyisocyanace A 0 25.8 0.3 2X of polyisocyanate A 1.6 25.9 8.6 4X of polyiso~yanate A 3.2 21.6 8.3 8X of polyisocyanate A 6.4 19.7 8.0 A Comparative Experiment, using sLmilar amounts of a commercially available wet-strength agen~ (15~ aqueous ~olution of a polyamidoamin2 which had been reacted with epichlorohydrin),gaVe the following contrasting re~ults:
:

Le A 26 857 ~ 18 " .

2G~932~

~ctive ~se~lclng Bra~lking subse~nc~ ~train ~trAln c~n~ tr~tion dry ~ot IX] [~1 [N~
~
5X of pl~lya~ido~in~ rosin O 25 . 8 0. 3 2X of polyff~îdo~nine r~n 0. 3 26 . 7 3 .4 4X of lpolya~do~ine ros~n 0.6 29 4.6 8X ~f polya~idoa~ r~in 1. 2 33 . 3 6 .1 la Thu~ the soft~r p~per tre~ted with polyl~ocy~na~OE ~, containing 1. 6~ of ~ctiv~ tance ~2~ of th~ IB0~
~olution) ~ h2ld a h~gher wet bre2lking ~train than the paper treated with the commerci~lly avail~lble wet-strength ~gent, containing 1.2% of active ~ubst~nce (8%
of the 15% ~olution). ~ors30ver, neither inorganic nor organic~lly bonded chlorine i8 releAsed ~hen polyisocyanate P. i~ u~ed.

,~
Papers with a basic weight of 80g/m2 comprising 80~6 softwood pulp and 20% hardwood pulp were produced without wet-strength agents at a pH of 7 with a degree of beating of 35 ~ SR . The papers were treated in a laboratory sizing press of type ElF made by the Mathis company, Zurich, Switzerland. The liquors employed were solutions or emulsions containing 0.3%;
0.6~, 0.9% and 1.2% of the water-dispersible polyigocyanateA.

Ls A 28 857 ~ l9 ~

. ~ . .
.'~ ' ' ,, , 2~32~

The liquid uptake of th~ paper was 100%. The p~per~
were dried at 85 C for 8 minutes and then coDden~ed for 10 minute~ at llO~C. ~or compari~on purposes a ~nown commercially available polyamidoamin~ resin w~s tested at the ~ame tLme. The ~et breaking strain ~f the paper 3heet3 wa~ tested a3 described inExamplel.

The results surpri~ingly ~how that the paper obtained by the process of the invention had a considerably higher ~et strength than when uRing the commerci~lly ~vailable polyamidoamine resin.

: Product Wet breakiny strain [N~
of condensed paper using a content of active compcund of:
0.3% 0~6% 0.9% 1.2%

polyisocyanate A 13.3 15.8 17.0 17.6 polyamidoamine resin 7.0 9.5 11.5 13O6 xample 3 This example shows the effecti~eness of the polyi~o-cyanates accordiny to the invention ~hen applied to the paper stock.

~ mixture of 50% bleach~d birch sulphate pulp and 50%
bleached pine sulphate pulp with a consistency of -~ 2.5% was beaten in a hollander to a degree of beating of 30- Schopper-Riegler. lOOg of the mixture placed in a beaker and diluted ~ith water to 1000 ml.

The quantitie~ of polyi~ocyanate A mentioned in the following table (ba~ed on the ~ibre ~took) were introduoed into the beaker in the form of an aqueou`s 301ution.

Le ~ 28 857 - 20 -2~3~

~fter a ~tirring time of 3 m~nut~s, the co~tent~ of the beakers were u~ed to produce, on a ~heet former (~apid-Kothen apparatus), ~heets of paper weighing approx. 80 m2/g. The sheets of paper were dried at B5-C for 8 minu~es under Yacuum at 30 mbar and after-cured in a drying cabinet for a further 10 minutes at llO-C.

After conditioning, fi~e 1.5 cm wide test strips w~re ~:
cut out of each sheet of paper and iMme~aed in di3tilled water ~or 5 minutes. The wet strips wore then tested immediately ~or their wet breakins ~tr~in ~, in a tensile testçr. A commercially a~ailable wet-strength agent with a high organic chlorine cont~nt was also tested in parallel as a standard.

It was surprisingly found that the paper containing polyisocyanate A acsording to the in~ention already had very good wet strength before condensation (drying at 85-C for 8 minutes). With the commercially available wet-strength agent, the ~nd Yalues were only obtained after condensation (llO-C
or 10 munutes)~ The following results were obtained:

Le A 28 857 - 21 - -~

2 ~ t~

Product X act~ve Wet bre~king ~train IN]
substance uncondensed c~ndens~d Polyamido2mine resin 0.075 1.4 3.6 n 0.15 2.8 7.0 " 0.3 4.3 10.5 n 0 .45 5 . 414 . 3 r 0.6 6.5 15.6 n 0.75 7.4 16.9 tl 0.9 8.~i 19.6 " 1.2 8.8 22.0 Polyisocyanate A 0.08 3.4 4.4 n 0.16 5.0 6.0 0 . 32 7 . 4 10 .1 n 0.48 8.5 11.6 n 0.64 9.2 12.1 n () . 8 9 . 4 12 . 7 n 0 . 9 6 10 . 5 14 . 3 :
1.28 11.3 14.7 n 1. 6 12 15 This serie~ wa~ repea~ed with the difference that a mixture of the two products w~s ~l~o tested:
;

~e A 2E1 857 - 22 -.-. . ,:. ~. --. . , ' ~3~

Product W~t-strength Acti~e Br~akl~g ~g~t ~bst~nce strain [N]
S [Xl [X]dsy wet P~lyamldc~min~ r~sin 1 0.1590.1 6.9 n 2 0-3 95.1 10.5 n 4 0 . 6 100 . 3 16 Polyis~cyan~te A 0.5 0.4 90.4 8 ~ 1 0.895.2 10.6 n 2 1. 696 12 . 8 .
Mixture of Polyi~ocya~ate A 0. 5 0 . 4 Polyamidoami~ r~sin 1 0.15100. 8 19.5 The symerqistic effect is apparent here. 0.4~ of polyisoc:yanate A on its own produces a wet breaking ~train of 8 N, 0.15% of polyamidoamine resin on it~ own producesl a wet breaking ~train of 6.9 N, bu~ a eombination of the two agents gi.ves a wet breakinq ~train 19.5 ~.

~4 Example 3 was .repeated using isocyanate B:

Le A 28 857 - 23 ~3~

Polyi30- A~ou~t of wet- ~ctive s~bst~nc~ ~e~ brelllcing cy~nat~ strength agan~ ~train {xl 1~] IN]

B 5~.5 0.5 3.7 ~S 1.0 1~0 6.1 1~) ~C~plQ5 Paper ~tock6 ~uch a~ those suitable for the ~anuf~cture ef p~per~ ~or lamination ( 20~ of ~hort ~ibre~, 8096 of long fibre~; 6096 of titanium dioxide, basad thQxPon) wer~
treated irl a first te6t pa~s with a commercially ~Yailable 15 per cent wet-strenqth agent ~poly~nidoamine re in), in a 8econcl te~t pass with polyi~ocyanate ~ and in a third te8t pa813 with a mixture of t:his polyi80c~ anate ( ~a~
~able for percen~ag~e added) and in ea~h ca~e 0 . SP6 o:E a cs:)mmercially avail~ble ratention agent ~ ~ a polya~ine ~ubst~ntially in the fo~ of the quaterni~ed Ghloride).
2~ ~he result~ of the wet breaking Btr~ain test b~re as foll~:

Le A 28 857 - 24 -2 ~

Produet ~t-strength Aetive W~t o~h a~ent ~ub~tane~ brea~lng : .
~tr~ln IX~ IX] IN~ IX

Polyamid~a~ine re~in 1 0.15 2.1 20 n 2 0.3 3.9 22.5 n 3 0.45 5.5 23.9 r 4 0.6 8.1 24 n 5 0.75 8.5 24.8 '1 S 0.9 11 25.3 ~ 8 1.2 13.3 25.1 ':

Polyisocy~nate A 0.1 0.08 2 12.1 0.2 0.16 3.5 12.1 0.4 0.32 5.1 11.3 n 0.8 0.64 5.8 11.6 n 1.2 0.96 6.3 12.3 ~ 2.0 1.6 7.6 12.~

Polyisecyanate A with 0.1 0.08 1.7 21.3 0.5X of retent~on 0.2 0.16 2.6 21.8 agent X added i~ eaeh 0.4 0.32 3.0 19.9 : 25 case (corresponding to 0.8 0.64 4.3 22.4 0.125Z of aet~ve 1.2 0.96 4.4 22.4 substance) 2.0 1.6 4.7 23.8 :~

As can be ~eerl from t~e Table, the wet breaXing strain in the lower operative range, based on active substance, is . ~:
'-. :

' Le P. 28. 857 ,. ~.

~,.~ .

, , 2 ~3 r ~ c3~ 1~ 8 9 higher w~h polyisocyanate A ~han with th~ wet-s~rength ~gen~ of the st~te of the ært, but a3 evidenced by the ~h ~alue - the re:tention effec~ i8 ~maller. ~Iowever, as also Yhown in the Table, the retent~on effect c~n be raised to the desired level by an addi~ional retentio~
agent.

~am~le_6 This example illustrates the effect of the wet-strang~h agent on the degree of whiteness of a ln brightened paper. The test was carried out according to Example 3 while additionally adding 0.5% of a commercially a~ail~ble optical brightener.

~et-strength agent Amount of Active Degree of wet-serength substance whiteness agent IX] lX] CIE

Polyis~cy~nate A O 0 129 n 0. 2 0.16 125 ~ 0.5 0.4 128 n 1.0 0.8 128 n 2.0 1.6 129 Polyamidoamine resin O 0 129 n 2 3 ~09 n 4 0.6 99 ~1 6 0 . 9 99 n 8 1. 2 98 In centra~t to the com~erci~lly a~ail~bla poly~midoamine re~in w~t-3trength ~gent, no ~rop in ~h~ degree of whiteness according to IS0 TC 38 (t2xtile) i8 ob~erved when uslng polyi~ocy~nate A according to tha in~ention, i.e. no quenching of the brightener t~ke~ place.

Le A 28 857 -26 ~

Claims (7)

1. paper or paper-like materials, characterised in that the paper ox paper-like material or the pulp used for producing the paper or the paper-like material is treated with water-dispersible polyisocyanates.
2. Process according to Claim 1, characterised in that the water-dispersible polyisocyanates used are:
(I) water-dispersible non-ionic polyisocyanate mixtures of polyisocyanates and polyisocyanates modified by polyethers and containing cycloaliphatically and/or aliphatically bonded isocyanate groups, (II) polyisocyanate mixtures of polyisocyanates and polyisocyanates modified by carboxylate groups and containing cycloaliphatically and/or aliphatically bonded isocyanate groups, or (III) water-dispersible non-ionic polyisocyanate containing aromatically bonded isocyanates.
groups, or mixtures of such polyisocyanates.
3. Process according to Claims 1 and 2, characterised in that the water-dispersible polyisocyanates used are water dispersible polyisocyanates (I) with a) a mean NCO functionality of 1.8 to 4.2, b) a content of aliphatically and/or cycloaliphatically bonded isocyanate groups (calculated as NCO, molecular weight = 42) of 12.0 to 21.5% by weight, based on the polyisocyanate mixture (I), and c) a content of ethylene oxide units situated within polyether chains (calculated as C2H4), molecular weight = 44) of 2 to 20% by weight, based on the polyisocyanate mixture (I), the polyether chains having a statistical mean of 5 to 70 ethylene oxide units.
4. Process according to Claims 1-3, characterized is that the water-dispersible polisocyanates are used in amounts of 0.005 to 50% by weight, based on the paper stock.
5. Process according to Claims 1 to 4, characterised in that the water-dispersible polyisocyanates are used as mixtures with conventional retention or wet-strength agents.
6. Process according to Claims 1 to 5, charac-terised in that the pulp used for the production of the paper or paper-like material is treated by adding the water-dispersible polyisocyanates in the form of an aqueous emulsion or directly to the pulp.
7. Process according to Claims 1 to 6, charac-terised in that the paper or the paper-like material which is in the form of a finished base paper is surface-treated.
CA002093289A 1992-04-06 1993-04-02 Process for imparting wet strength to paper Abandoned CA2093289A1 (en)

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DEP4211480.2 1992-04-06

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5688371A (en) * 1994-03-21 1997-11-18 Bayer Aktiengesellschaft Process for fixing disruptive substances in papermaking
US5961783A (en) * 1997-06-06 1999-10-05 Vinings Industries, Inc. Process for enhancing the strength and sizing properties of cellulosic fiber using a self-emulsifiable isocyanate and a coupling agent

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2189992A1 (en) * 1994-05-11 1995-11-23 Jurgen Reiners Paper finishing aid
DE4436058A1 (en) * 1994-10-10 1996-04-11 Bayer Ag Process for the manufacture of cellulose-containing sheet materials equipped with dry and / or wet strength
DE4444489A1 (en) * 1994-12-14 1996-06-20 Technocell Dekor Gmbh & Co Kg Base paper for decorative coating materials
DE4446334A1 (en) * 1994-12-23 1996-06-27 Bayer Ag Reclosable cellulosic materials
DE19516405A1 (en) * 1995-05-04 1996-11-07 Bayer Ag Process for producing structurally stable papers
DE19520092A1 (en) * 1995-06-01 1996-12-05 Bayer Ag Process for paper finishing using polyisocyanates with anionic groups
DE19548025A1 (en) 1995-12-21 1997-06-26 Bayer Ag Process for the production of degradable microcapsules
DE10108349A1 (en) * 2001-02-21 2002-08-29 Basf Ag Paper coatings
JP2003138497A (en) * 2001-10-31 2003-05-14 Dai Ichi Kogyo Seiyaku Co Ltd Wet paper strength-reinforcing agent
US6709758B2 (en) * 2001-11-09 2004-03-23 Lord Corporation Room temperature curable X-HNBR coating
US6777026B2 (en) * 2002-10-07 2004-08-17 Lord Corporation Flexible emissive coatings for elastomer substrates
AU2003234159A1 (en) * 2002-04-22 2003-11-03 Purdue Research Foundation Hydrogels having enhanced elasticity and mechanical strength properties
CA2992243C (en) 2007-10-19 2021-01-12 Lord Corporation Suspension system for aircraft auxiliary power unit with elastomeric member
WO2018060002A1 (en) * 2016-09-30 2018-04-05 Kemira Oyj A method for increasing dimensional stability of a paper or a board product
CN107881849A (en) * 2016-09-30 2018-04-06 凯米罗总公司 For the method for the dimensional stability for improving paper or board product

Family Cites Families (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3049469A (en) * 1957-11-07 1962-08-14 Hercules Powder Co Ltd Application of coating or impregnating materials to fibrous material
NL231136A (en) * 1957-09-05
GB940771A (en) * 1959-06-02
US3311608A (en) * 1963-02-12 1967-03-28 John P Murphy Cellulose isocyanate-aliphatic polyamine ion-exchange composition and method for making same
US3332901A (en) * 1966-06-16 1967-07-25 Hercules Inc Cationic water-soluble polyamide-epichlorohydrin resins and method of preparing same
US3589978A (en) * 1967-09-29 1971-06-29 Gen Mills Inc Process of making water repellent paper using a fatty polyisocyanate and a cationic gum ether and product therefrom
US3925283A (en) * 1970-06-29 1975-12-09 Continental Tapes Inc Polyurethane pressure-sensitive adhesive products and processes
US3761307A (en) * 1970-06-29 1973-09-25 R Dahl Process of making polyurethane pressure sensitive adhesive tape
US3748329A (en) * 1970-07-08 1973-07-24 Bayer Ag Compounds containing the 2,4,6-triketo-1,3,5-oxadiazine ring
DE2264699A1 (en) * 1972-03-04 1974-08-01 Anchor Continental Inc Polyurethane-forming, catalysed, solns. - used in mfr. of adhesives and paper impregnants to increase dry-and wet-strength
GB1502777A (en) * 1974-09-12 1978-03-01 Ici Ltd Polyurethane foams
DE2703271C3 (en) * 1977-01-27 1980-02-14 Basf Ag, 6700 Ludwigshafen Preparation of aqueous isocyanate emulsions
GB2018796B (en) * 1978-03-29 1982-07-28 Ici Ltd Emulsifiable compositions
EP0013112A1 (en) * 1978-12-27 1980-07-09 Imperial Chemical Industries Plc Emulsifiable compositions and aqueous emulsions of organic isocyanates, and process using them as binders for manufacturing lignocellulose sheets
FR2453936A1 (en) * 1979-04-10 1980-11-07 Du Pin Cellulose PAPER OR CARDBOARD PROCESSING
DE3102038A1 (en) * 1980-01-28 1981-12-10 W.R. Grace & Co., 02140 Cambridge, Mass. POLYURETHANE POLYMER AMINE SALT AS A PAPER ADDITIVE
DE3110203A1 (en) * 1981-03-17 1982-09-30 Rolf 6450 Hanau Corvinus Process and apparatus for cleaning a swimming pool
DE3112117A1 (en) * 1981-03-27 1982-10-07 Bayer Ag, 5090 Leverkusen USE OF WATER DISPERSABLE POLYISOCYANATE PREPARATIONS AS ADDITIVES FOR AQUEOUS ADHESIVES
US4547265A (en) * 1983-06-01 1985-10-15 American Cyanamid Company Method for sizing paper using hydrolyzed homopolymers or copolymers of meta- or para- isopropenyl-α,α-dimethylbenzylisocyanate
US4505778A (en) * 1983-09-06 1985-03-19 Ici Americas Inc. Paper products sized with polyisocyanate blends
DE3521618A1 (en) * 1985-06-15 1986-12-18 Bayer Ag, 5090 Leverkusen POLYISOCYANATE PREPARATION IN WATER AND THEIR USE AS ADDITIVES FOR AQUEOUS ADHESIVES
DE3523856A1 (en) * 1985-07-04 1987-01-08 Bayer Ag AQUEOUS SOLUTIONS OR DISPERSIONS OF POLYISOCYANATE ADDITION PRODUCTS, A METHOD FOR THE PRODUCTION THEREOF, AND THEIR USE AS A COATING OR SIZING AGENT FOR PAPER
FR2593839B1 (en) * 1986-01-24 1988-04-29 Atochem LATEX OF DIURETHANE AS A GLUING AGENT IN THE PAPER INDUSTRY, ITS MANUFACTURING METHOD
DE3700209A1 (en) * 1987-01-07 1988-07-21 Bayer Ag METHOD FOR PRODUCING POLYISOCYANATES WITH BIURET STRUCTURE
DE3811350A1 (en) * 1988-04-02 1989-10-19 Bayer Ag METHOD FOR THE PRODUCTION OF ISOCYANURATE POLYISOCYANATES, THE COMPOUNDS OBTAINED BY THIS PROCESS AND THEIR USE
DE3814167A1 (en) * 1988-04-27 1989-11-09 Bayer Ag METHOD FOR PRODUCING POLYISOCYANATES CONTAINING ISOCYANURATE GROUPS AND THE USE THEREOF
DE3900053A1 (en) * 1989-01-03 1990-07-12 Bayer Ag PROCESS FOR THE PREPARATION OF POLYISOCYANATES USING URETDION AND ISOCYANATE GROUPS, THE POLYISOCYANATES AVAILABLE FOR THIS PROCESS, AND THEIR USE IN TWO-COMPONENT POLYURETHANE VARNISHES
DE4001783A1 (en) * 1990-01-23 1991-07-25 Bayer Ag POLYISOCYANATE MIXTURES, A PROCESS FOR THEIR PRODUCTION AND THEIR USE AS A BINDER FOR COATING AGENTS OR AS A REACTION PARTNER FOR ISOCYANATE GROUPS OR CARBOXYL GROUPS REACTIVE COMPOUNDS

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5688371A (en) * 1994-03-21 1997-11-18 Bayer Aktiengesellschaft Process for fixing disruptive substances in papermaking
US5961783A (en) * 1997-06-06 1999-10-05 Vinings Industries, Inc. Process for enhancing the strength and sizing properties of cellulosic fiber using a self-emulsifiable isocyanate and a coupling agent

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