Note: Descriptions are shown in the official language in which they were submitted.
~ 212~9~
O.Z. 0050/44008
Use of an aq~eou~ polYurethane disPer~ion
a~ an adhesive
The pre~ent invention relates to the use of an
aqueous polyurethane disper~ion a~ an adhesive. In order
to avoid Rolvent wa3tes and solvent emis~ions, aqu ous
polymer disper~ions, in particular polyurethane disper-
sions, are increasingly being used a~ adhesives. Poly-
urethane di~persion~ are described in, for example, DE-A-
39 03 538 and DE-A-14 95 745. Sinco the mechanical
properties, in particular the heat di~tortion re~istance,
of adheeive bonds obtainable with such di~persions are
often inad~quats, they are cros~linked, for example by
adding polyiYocyanate~, a~ de~aribed in, for example,
EP-A-02 08 059 and ~S-A-47 62 880. However, thi~ type o~
cros~linking has the di~advantage that the pot life, ie.
th~ time which ramains for proce~ing after the addition
of the cro~sli~king ageut, i8 vsry ~hort.
The cros~linking o~ polyurethane di0per~ion~ by
means of polyvalent metal comploxe~ i~ di~clo~ed in EP-A
228 481, which r~latea to ramovable floor coatings.
The unpubliehod German Patont Application
P 4137556.4 di~close~ polyurethane di~p~rsions which
contain an adheeion-improving polymer and inorganic
salts.
It ie an obj~ct of th~ ~reeent invention to
improve the mechanical propertie~, in particular the heat
di~tortion resietance, when polyur~thane di~persion~ are
u~ed a~ an adhesive.
We ha~ found that thi~ object ie achieved by th~
use of aqueou~ di~per~ione, containing a polyurethane
which i~ essentially compo~ed of
a) organic polyiaocyanatas,
b) polyhydroxy compound~ having a molecular weight of
from above 500 to 5,000 g/mol,
c) compou~ds having at- leaBt one group reactive toward
ieocyanate and having at leaet on~ ionic group or
group con~ertible into an io~ic group and
; ~ , . .. .
2~21g~9
2 - O.Z. 0050/44008
d) if required, compounds which differ from (c) and
ha~e at least two functional groups reactive toward
i~ocyanate and a molecular weight of from 60 to
500 g/mol,
and at least one chelate complex comprining a poly~alent
metal as tha central atom and a polydentate ligand, as an
adhe~ive. We have al~o found aqueous dispersions which
are auitable for u~e as an adhesive.
The polyurethane i~ e~sentially, preferably
exclusi~ely, compo~ed of the componant~ a-d). The
functional groups reaative toward i~ocyanate are hydroxyl
or primary or secondary amino group~
Suitable polyi~ocyanats3 (a) are in particular
aliphatic, cycloaliphatic and aromatic dii~ocyanates.
1~ Tho~e of the general formula X(NC0) 2~ where X is an
aliphatic hydrocarbon radical of 4 to 12 carbon atomn or
a cycloaliphatic or aromatic hydrocarbon radical of 6 to
15 carbon atoms, are pr~ferably u0ed.
Example~ of suitabl~ aliphatic, cycloaliphatic
and aromatic diiaocyanates are butane 1,4-dii30cyanate,
hexane 1,6-dii~ocy~nate, 2,2,4- and 2,4,4-trimethyl-
hexamethylene diisocyanate, cyclohexa~e dii~ocyanate,
methylcyclohexane diisocyanate, isophorone dli~ocya~ate,
4,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanato~
dicyclohe~ylmOEthane, toluylene 2,4- and 2,6-dii0ocyanats
and tetramathylxylylene dii~ocyanato (TMXDI).
Mixture~ of the dii30cyanate~ may al80 be u~ed.
Mixtures o~ aliphatic or cycloaliphatic dii~ocyanate~
with aromatic diisocyanates in a molar ratio of from
1 : 4 to 5 : 1 have pro~en particularly ~uitable.
In addition to the dii30cyanates, it i8 al~o
po~sible to uae minor amount~ of monoiaocyanates for
molecular weight regulation.
Compound having more than 2 isocyanate group~,
such as bluret~ or i~ocyanuratee, or example those of
iaophorone diisocyanate or hexamethylene 1,6-
diiaocyanate, may also be pre~ent.
.. . - . ~
- . - .
.. . ,
.:. . :
` 21219~9
,~ ~
_ 3 _ o.Z. 0050/44008
Suitable polyhydroxy compounds, in partiaular
dihydroxy compound~ (b), having a molecular weight of
from abo~ 500 to 5,000 are the known polyesters, poly-
etherEi, polythioethers, polylactone~, polyacetals, poly-
carbonate~ and polyesteramide~ having 2 hydroxyl groups.Preferred dihydroxy compounds are those who~e molecular
weight i3 ~rom 750 to 3,000. Mixturo~ of these dihydroxy
compounds can of course al~o be u~ed.
If nece0sary, compounds with more than 2 hydroxyl
group~, for example glycerol or trimethylolpropana
alkoxylated with polypropylene oxide, may additionally be
used.
Example~ o~ ~uitabls components (c) which di~er
from (b) are aliphatic, cycloaliphatic or aromatic mono-
or dihydroxycarboxylic acid~. Dihydroxyalkanecarboxylic
acids, in particular of 3 to 10 carbon atom~, as al o
de~cribed in US-A-3 412 0S4 are preferred. Compound~ o~
the general formula
COO
HO~ R2 - C - R3 - OH
R~
whero Rl iB hydrogen or alkyl o 1 to 4 aarbon atom~ and
Rl and R3 are each Cl-C~-alkylene, are particularly prerer-
red. ~n ex~mple i~ 2,2-dimethylolpropionic acid.
Tertiary ammonium ~alt~ containing one or two
hydroxyl or amino groups and aminocarboxylic acids or
amino~ulo~ic acids, for example ly~ina, alanine, N-(2-
aminoethyl)-2-aminoethane~ulfonic acid and the adduct~ of
aliphatic d~pximary diaminer~ with ~-ole~inic carboxylic
acid~, di~clo~ed in DE-A-20 34 479, for example the
adduct o~ ethylenediamine with acrylic aoid, are alr~o
noteworthy.
Component (c) contains ion~c group~ or groups
convertible into ionic group~i, in order to en~ure tho
.,.: :.
2~21~9
- 4 - O.Z. 0050/44008
di~persibility of the polyurethane in water. Its content
is u~ually from 0.03 to 0.5, preferably ~rom 0.05 to 0.4,
gram equivalent, based on 1 mol of i~ocyanate group~.
Inorganic and/or organic bas~, such as ~odium
hydroxide, potaa~ium hydroxide, potassium carbonate,
sodium bicarbonate, ammonia or primary, 3econdary and in
particular t~rtiary aminQs, eg. triethylamine or
dimethylaminopropanol, can be used for con~erting
pote~tial anionic group0, for example carboxyl groupa or
sulfQ groups, into ionic groups.
For the con~er~ion o~ the potential cationic
groups, for example the tertiary amino group~, into the
corresponding cations, for example ammoni~m group~
inorganic or organic acid~, for ~xample hydrochloric
acid, acetic acid, fumaric acid, maleic acid, lactic
acid, tartaric acid, oxalia acid or pho~phoric acid are
~uitable a~ neutralizing agents or, for example, methyl
chloride, methyl iodide, dimethyl sulfate, benzyl
chloride, ethyl chloroacetate or bromoacetamide are
suitable a~ quaternizing agent~. Further suitable
neutralizing and quaternizing agents are de3cribed in,
$or example, U.S. Patent 3,479,310, column 6.
The neutralization or quaternization o the ionic
or o~ the potentially io~ic group~ ca~ be carried out
be~ore, durins and in particular after tha isocyanate
polyaddition reaction.
I~ nece~sary, nonionic emul~i4i0rs, ~uch a~
monohydr~c polyether alcohols having a molecular weight
of from 500 to 10,000, preferably rom 1,000 to 5,000,
g/mol may also be present. ~owever, t~e use of nonionic
emulsi~ier~ i8 generally not ne~essa~y, owing to the
pre~ence o~ compound~ c).
Component3 d) are e~entlally compounda which
contain two hydroxyl group~, two amino group~ or one
hydroxyl and ona amino group. For example, dihydroxy
compounds, such a~ 1,3-propansdiol or 1,4-butanediol,
diamines, ~uch a~ ethylenediamine, hexa~ethylenediamine,
-` 21219~
- 5 - o.Z. 0050/44008
piperazine, 2,5-dimethylpiperazine, ~-amino-3-amino-
methyl-3,5,5-trimethylcyclohexane (isophoronediamine),
4,4'-diaminodicyclohexylmethane, 2,4-diaminocyclohexane,
1,2-diaminopropane or hydrazi~e, or amino alcohols, ~uch
5 a3 ethanolamine, i~opropanolamine, methylathanolamine or
aminoethoxyethanol, are ~uitable.
Compou~ds having at least 3 groupR reactive
toward isocyanate may al80 be suitable, for example
-- triols, auch as trimethylolpropane or glyc~rol, or tri-
hydroxy aompounds havi~g ether or est~r groups, aB well
a3 pentaerythritol aa a tetrahydroxy co~pound, triamine
compounds, ~uch a~ diethylenetriamine, 4-aminomethyl-
octanediamin~ or trisaminoethylamine, and compound3
containing hydroxyl and amino groups, Quch as
diethanolamine.
The total content of the components ia preferably
chosen 80 that the sum of the hydroxyl and primary or
~econdary amino groups reacti~e toward iaocyanate i8 from
0.9 to 1.3, particularly preferably from 0.95 to 1.1,
based on 1 isocyanata group.
For the preparation of the polyurethane, the
component~ a) to d) can be reacted in a known manner in
a low-bolling, water-mi~cible, organic solvent or in the
ab~ence o4 ~olvents, a~ al80 described in DE-A-34 37 918.
A11 solvents whi~h are unreactive toward iso-
cyanate may ba used a~ the ~ol~ent. Tho~e which are
infinitely mi~ible with water, for example tetrahydro~
~uran, methyl ethyl k~tone, N-methylpyrrolidone and in
particular acetone, ara particularly preferred. ~igh-
boiling, water-miacible sol~ents, ~or example N-methyl-
pyrrolidon2 or dimethylformamide, are less preferable.
Water-immis~ible ~olventR, ~or ~xample toluene or xylene,
may al~o be present in minor amount~. The boiling point
o~ the sol~ent i8 pra~erably below 100C.
The reaction tempera~ure is preferably from 50 to
120C.
Con~entional and k~ow~ cataly8t8, BUCh as
- . . .
,: ,. :
-, ~ ,,, : ' ', , :
2121g~9
`~
- 6 - .Z. 0050/4400
dibutyltin dilaurate, tin(II) octoate or 1,4-diaza-
bicyolo[2.2.2]octane, may be present for acc~lerat~ng the
reaction of the dii~ocyanate
The re~ulting polyurethana, which ie essentially
free of isocyanate group~ then di~per~ed in water and
the organic ~olvent i~ r~mo~ed to the de~ired extent, in
general completely, by di~tillation.
The polyurethane may al~o be prepared by
initially preparing a polyuretha~e prepolymer in an
organic 301vent. After the addition of the reaction
product, the resulting polyurethane prepolymer, which
still contain~ isocyanate group~ diRpersed in water.
The reaction with the further component~ can then be
carried out. The organic 301vent ca~ the~ be removed, a~
de~cribed above.
The agueou~ dispersio~ co~tains, i~ addition to
the polyurethans, at 19a8t one chelate complex co~prising
a polyvalent metal a~ ths ce~tral atom and a polydentate
ligand.
The amount by weight o~ thi~ co~plex i~ prefer-
ably ~rom 0.01 to 10, particularly preferably ~rom 0.01
to 5, very particularly pre~erably ~ro~ 0.02 to 2.5, % by
weight, ba~ed on the polyurethane.
The polyvalent metal i~ pre~erably ~alected ~rom
the group con~i~ting of the ele~ent~ ~g, Ca, Sr, Ni, Ba,
Al, Mn, Fe, Zn, Ti, Cu and Zr.
Mg, Ca, Zn, Al and Zr are particularly pre~erred.
At l~a~t ona ligand o~ the central atom i~ poly-
de~tate, ie. ha~ two or mor~ coordinat~ bond~ to the
central atom, but pre~erably all ~uch ligand3 are
polydentate.
Such coordinate bond~ are usually ~ormed between
group~ ~uch a~ primary, ~eoondary or tertiary a~ino
group~ or sthylen~ oxide, carboxyl, carboxylate, keto,
aldehyde, nitril~ or mercapto group~ or aromatic, ie.
phenolic hydroxyl group~ and the c~ntxal metal atom.
The ~ormatio~ constant K~ ~or the formation of a
121~59
- 7 - O.Z. 0050/44008
complex of a central metal atom ~ and one of the poly-
dentate ligand~ L is preferably calculated aa log RF from
~ ~-
K, =
~ a~
the values obtained being from 3 to 15 (a = activity, cf.
also Anorganikum, Berlin 1977, 7th Edition, page 497).
Examples of polydentate liyand~ are dinitrilo-
tetraacetic acid, pyrocatechol, acetylacetone, 2,2'-
bipyridyl, ethylenediamine, diethylenediamine, tri-
ethylenediamine and crown ether~.
Preferred chelate ~omplexea are neutral complexes
which carry no positi~e or negative charge.
The acetylacetonate~, in particular those of
alum1num and of zirconium, are very particularly
preferred.
The chelate complexes may be added to the poly-
urethane or to the polyurethane dispersion at any time
hefore, during or after the preparation of the poly-
urethane. The chelate complexa~ are preferably added inthe form of an organic aolution, suitable 501vent8 being,
for example, the abovementioned ~ol~ents in the prepara-
tion of the polyurethane. Th~ chelate comple~e~ are
preferably added to the polyurethane before di~per3ing in
water.
The aqueous di~per~ion which i~ u~ed according to
the inventio~ a~ an adhesive may furthermore contain an
adhe~ion-improving polymer. The ~mount by weight of
the~e polymers ~ay be from 5 to 60, pre4erably from 5 to
30, % by weight, based on the polyurethane.
The adhe~ion-impro~ing polymer i8 likewiae added
to the polyurethane or to i~s prepolymer in water pref~r-
ably befor~ di~persing. In the ca~e of the prepolymer~,
the further reaction to give the polyurethane i~ then
carried out.
Suitable adhe~ion-improving poly~ers are a large
nu~ber of different polyconden~ate~, freo radical poly-
mera or polyadduct~.
21219~9
- 8 - O.Z. 0050/44008
The adhesion-impro~ing polymQrs are preferably
phenol/formaldehyde conden~ation re~in~ or similar
reaction products (in particular phenol resin3) of a
compound (I), ~elected from the group consisting of
aromatic compound~ having one aromatic ring, two fu~ed
aromatic rings or two aromatic ring~ which are bonded by
a Cl-C9-alkylene and are sub~tituted on at lea~t one ring
by at least one hydroxyl group and are unsub~tituted or
- substituted on the aromatic ringa by from 1 to 3 Cl-Cl2-
alkyl or Cl-Cl2-alkoxy group~, and the mixture~ of the~e
aromatic compounds with a compound (II) ~elected ~rom the
group con3i~ting o~ compounds having 1 to 20 carbon atom~
and at lea~t one keto or aldehyde group, a C4-Cl8~
diolefin, co~pounds having 2 to 10 carbon atom~ and at
lea~t one triple bo~d and mixture~ thereo~ :
Preferred co~pound~ (I) are ~- or ~-naphthol,
bisphe~ol A or phenol which i~ un~ubstituted or 8ub-
3tituted by ~rom 1 to 3 Cl-C8-alkyl or alkoxy groups. The
3ub~titue~t~ are preferably mata or para to the hydroxyl
group on the aromatic ring~. Un ub~tituted phenol, a-
and g-naphthol and bisphenol A are particularly
prefer~ed.
Preferred compounds (I) ar0 co~pound~ which hav~
one or two hydroxyl group~, parti~ularly preferably one
hydroxyl group.
Compounds (II) are pr~ferably compounda ha~ing 1
to 14 carbon ato~s and ono or two keto or aldehyde
group~, preferably one keto or aldehyde group. The~o
compound~ may be aliphatic or aromatic or ~ay contain
both aliphati~ and aromatic group3. In addition to thz
keto or aldehyde group, the compound~ preferably contain
no ~urther ~unotional groups, ie. no ~urther heteroatom~
apart from the oxygen atom o~ the aldehyde or keto group.
~xamplo~ of compound~ (II) are $ormaldehyde,
acetald~hyde, n-propionaldehyde, glycolaldehyde, i~o-
propionaldehyda, n-butyraldehyde, isobutyrald~hyde, benz-
aldehyde, glyoxal, glutardialdehyde, oxaglutardialdehyde,
, ' ' ' ~ ' : ' ' , ' ' . '; ' ~ . '
21219~9
- 9 - O.Z. 0050/44008
acetone, methyl ethyl ketone, benzophenone, butadie~e,
cyclopentadiene and bicyclopentadiene, acetylene,
acrolein, methylacrolain or mixtures thereof.
Formaldehyde, acetaldehyde, propionaldehyde,
n-butyraldehyde, i~obutyraldehyda, acetone and mixtures
thereof are particularly preferred.
Reaction products of the compounds (I) and (II)
are generally known. The reaction take~ place similarly
to the phenol/formaldehyde condensation, by addition of
the keto or aldehyde group or o the double or triple
bond predominantly ortho or para to ths hydroxyl group on
the aromatic ring.
The molar ratio of the compound (I) to (II) in
the condensation reactio~ is pre~erably from 1 : 0.1 to
1 : 2, particularly preferably $rom 1 : 0.7 to 1 : 1.
The reaction i8 carried out in general by ini~
tially taking the compound (I) with an acid a~ a catal~
yst, for example a hydrohalic acid, boron trifluoride,
sulfuric acid, p-toluene~ulfonic aaid or dodecylbenzene-
sulfonic acid, and the~ meterin~ in the compound (II) at
O to 250C, pre~erably from 20 to 230C.
After the end of the ~etering, postco~densation
can be carried out, in particular at fro~ 20 to 250C,
preferably from 80 to 200C. During the reaction, water
can, if desired, be r~moYed from the reaction mixture, if
necessary with the use of an entraining age~t.
The cour~e of tha reaction can be monitored by
mea~uring the ~oftening point of the re~ulting reaction
product.
~he reaction prod~ct~ preferably ha~e a ~oftening
point (determined according to DIN 52,011) o~ from 50 to
200C, particularly preferably rom 80 to 140C, very
particularly prefexably rom 120 to 140C.
Epoxy resins, preferably reaction producta of
epoxide3, ~uch a~ epichlorohydrin, with bi~phenol A, are
also auitable; tho~e ha~ing weight average molecular
weight~ (-M~) of ro~ 500 to 5,000 and ~oftening poin~s
21219~)9
- 10 - O.Z. 0050/44008
of from 80 to 130C are preferred.
Other suitable adhesion-improving polymer~ are
polyvinyl acetate, polyvinyl chloride, polymethacrylates,
styrene/acrylonitrile copolymer~, polyamide~, polyethers,
polye~terR, polyetherdiol~, polye~terdiols, poly-
urethanes, in particular polyur~thane~ free of salt
group~, and phenacrylate.
Praferred polyvinyl acetates are the homopolymer~
of vinyl acetate. Ita copolymer~ which contain up to 10%
by weight of comonomer~ ~uch a~ vinyl laurate, vinyl
~tearate or, preferably, (meth)acrylic acids, fumarates
or maleate~ of Cl-C8~alkanols, such aE methanol, n-butanol
or 2-ethylhexanol, may al80 be used. The polymers
u~ually have a R value, mea~ured at 25C in cyclohexanone
according to DIN 53,726, of from 45 to 60. Polyvinyl
chloride i~ understood in general a~ meaning the homo-
pol~mers of vinyl chloride and its copolymers which
contain up to 10% by weight of comonomer~, such as
ethyl0ne or vinyl acetate. Their R value (25C, cyclo-
hexanone, DIN 53,726~ should be from 45 to 55. The
polymethacrylate~ used by the skilled worker are usually
homopolymers of methyl acrylata or it~ copolymers with up
to 10% by weight, ba~ed on the copolymer, of vinyl
acetats, acrylates of Cl-C8-alkanol~ or methacrylatea of
C2-C3-alkanol~. Their melt flow index MFI, determined
according to DIN 53,735 (230C/3.B kg), i~ in general
from 0.1 to 3Ø The~e polymero ara prepared in general
by free radical ma~, solution or ~mulaion polymerization
of the ethylenically unsaturated monomer3 at from 30 to
150C with sub~equent drying. Such polymers are
generally known, or example from ~o~ben-Weyl, Methoden
der organischen Chemle, Volume E20, l9B7, page~ 1115-
1125, 1041-1052 and 1141-1174.
guitable polyamide~ have a R value o~ from 65 to
80, mea~ured in H2SO~ at 25C according to DIN 53,727.
These ars u~ually pol~mers which are derived from lactams
having 7 to 13 ring membQrs, ~uch as ~-caprolactam,
"
,;:: . .: .: - . . .
21219~9
- 11 - O.Z. 0050/~4008
e-capryllactam or ~-laurolactam, for example polycapro-
lactam (PA6), and polyamide~ which are obtained by
reacting dicarboxylic acid~ with diamines. Examples of -- -
the~e are polyhexamethyleneadipamide (PA66), polyhexa-
methylene0ebacamide (P~610) andpolyhexamethylenedodecan-
amide (PA612). Examples of suitable dicarboxylic acids
are alkanedicarboxylic acids of 4 to 12, in particular 6
to 10, carbon atom3 and phthalic acid, terephthalic acid
and isophthalic acid, a~ well a~ any mixture~ of the~e
acids. Examples of diamines are alkan~diamine~ of 4 to
12, in particular 4 to 8, carbon atom~ and m-xylylene-
diamine, p-xylylenediamine, hydrogenated derivative~
thereof, bi~(4-aminophenyl)methane, bi~(4-aminocyclo-
hexyl)m0thane or 2,2-bi~(4-aminophenyl)propane or mix-
ture~ thereof. Owing to thoir good ~olubility, copoly-
mer~ are preferred, for example a copolya~ide of from 30
to 40% by weight of adipia acid, from 15 to 20% by weight
of hexamethyle~ediamin~ and from 30 to 35% by weight of
~-caprolactam or from 15 to 20% by weight or ~-amino-
caproic acid. The preparation of these know~ polymer~ i3
general technical knowledge, cf. for example Rompp,
Chemielexikon, 8th Edition, page~ 2861, 3058 and 3267, or
EP-A-129 195 and EP-A-129 1960
The polyetherdiols are known per 8e, for example
from Runst~toff-Handbuch 7 (1983), 42-54. Examplea are
polyethylene oxide, polypropylene oxide or polytetra-
hydrofuran or their copoly~er0 ha~ing two terminal
hydroxyl ~roups. They are prepared in a known manner by,
in general, anionic polyaddition, cf. for example N.~.
Gaylord, High Polymers, Vol. 13, New York 1963, Par~ I.
Polyetherol~, which are grated w~th ethylene oxide to
incr~ase the raactivity, are o~ minor importance. The
polyetherdioln generally have a ~olocular weight of from
300 to 3,000, corre~ponding to a K value of from 25 to 60
in D~F at 25C according to DIN 53,726. Preferred
molecular weight~ are from 800 ~o 2,200.
The polyether uaed is, for example, polyethylene
' ' '~ ": ~;
2~2~9~9
.~. ,
- 12 - O.Z. 0050/44008
oxide, polypropylene oxide or polytetrahydrofuran. The
polyether3 u~ually havs a R valu~ o_ 4rom 20 to 50 in DMF
at 25C according to DIN 53,726. They are generally
known, for example from Encyclopedia of Polymer Scien~e
5 and Technology, Volume 6, 1967, page 103 et seq., Voluma
9, 1968, page 668 et seq., and Volume 13, 1970, pag~ 670
et ~eq.
Preferred polyestera are monomer-free un~aturated
polyester resin~. These are known condensate~ of poly-
ba~ic, in particular dibasic, carboxylic acids or the
e~terifiable derivati~ thereof, in particular the
anhydride~ thereof which are esterified with polyhydric,
in particular dihydric, alcohols and may contain addi-
tional radical3 of monoba~ic carboxylic acid~ or mono-
hydric alcohol~. Examples o~ starting materials are
maleic acid, fumaric acid, phthalic acid, i~ophthalic
acid, terephthalic acid, malzic anhydride, phthalic
anhydride, isophthalic anhydride, ethylene glycol,
propylen~ glycol, 1,4-butanediol and neopentylglycol.
Re~in3 whi~h are prepared by condensing bisphenol A,
epichlorohydrin/bi~phenol A conden~at~ and mathacrylic
acid are of minor importanca ~or the purpose~ of the
pre~ent invention. In this context~ monomer-~ree mean~
the UP re~ins arc insoluble in the monomers ~uitable for
crosslinking, such a~ ~tyrene. The products usually have
a ~isco~ity of from 1,000 to 6,000, in particular from
2,000 to 4,000, m~a.a at 150C.
Suitable polyesterdiols are conden~ate~ which
have two terminal OH groups and are obtained 4 rom
dicarboxylic acid3, such aa adipic acid or isophthalic
acid, and diol~, for example 1,4-butanediol, 1,6-hexane-
diol or neopentylglycol.
The molecular weight range of the polye~terdiol~
which can be used i~ in general fro~ 300 to 5,000,
preferably from 800 to 2j500, corre~ponding to a ~ ~alue
o~ from 30 to 55 in DMF at 25~C according to DIN 53,276.
The~e polymor~ and their preparation are generally known
,.
`` 212~9~9
. ` .
- 13 - O.Z. 0050/44008
from Kunststoff-~andbuch 7 (1983), 54-62, and DE 12 68
842.
PolyursthaneE which are free of alt groups are
known addition polymer~ based on polyetherdiols or
polye~terdiols, isocyanates, ~uch a3 hexamethylene
diisocyanate, or 2,4-dii~ocyanatodiphenylmethane, and
po~sibly bi- or trifunctional chain extenders which are
prepared by conventional proce~se~ (Runststo~f-~andbuch,
Karl-Hanser-Verlag, Volume 7 (1966)). Low molecular
weight condensates (K value of from 25 to 60 in DMF at
25C according to DIN 53,726) are preferably u~ed.
Cros~linked polyurethane~ are of minor importance.
Phenacrylate~ are preferably prepared by subject-
ing bt~phenol A glycidyl ethera esterified with acrylic
acid or methacrylic acid to an addition reaction with
terephthalic acid. Phenacrylate~ based on epoxidized
novolako may alao be u3ed. The R value~ of the polymer~
are in general from 30 to 55 (in cyclohexane at 25C
according to DIN 53,726).
The aqueouR di~per~ion~ which, according to the
invention, are u~ed as adhe~ive~ and which contain a
chelate complex and may contain an adhesion-improving
polymer pref~rably have a solid~ content of from 10 to
70, in particular from 20 to 50, ~ by weight.
They can be used, for example, directly a~
contact adhe~ive~ for bonding a very wide range of
substrate~, ~or example wood, plastic, gla R and metal.
In order to obtain special propertie~, further additives,
such as pla~ticizers, ~ilm-~orming a~ tant~, fillers or
polyacrylate~, polyvinyl acetate~, 3tyrens/butadiene
copolymers a~ component~ of the mixturet etc., may be
added to the di~persion~. Advantageou~ly, adhe ive
coatings are applied to the ~ur~aces o~ both ~ub~trate~
to be bonded. ~ ~ -
The ~queou~ disper~ions give adhesive bond~
having high strength, in particular high heat di~tortion
resi~tance.
. ~ , ~ . . . :., .
.
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- 14 - O.Z. 0050/44008
EXAMP~ES
The abbreviations u~ed in the Example~ below have
the meaning~ given below:
AD~ = Adipic acid
sl4 = 1,4-~utanediol
TDI = Toluylene diisocyanata
D I = Hexamethylene dii~ocyanate
IPDI = I30phorone diisocyanate
PUD = Sodium salt of the Michael adduct of acrylic acid
and ethylenediamina
DBTL = Dibutyltin dilaurate
DMPA - Dimethylolpropionic acid
TMP = Trimethylolpropana
' '' ' - ' ~''
:. . : ~ : . .. , : : ' . . :
,: ' '' ', ~ , ' ' ' :' ' : .
` 21219~9
, ~ .
.
- 15 - O.Z. 0050/44008
EXAMPLE lA tComparative Example)
_
Molar amount Part~ by weight
~mmol~ ~g]
_
Polye~terdiol (OH number: 198 492
TDI 147 25.6
HDI 178 24.7
DBTL 0.1
Acetone I 133
.
Aceton~ II 532
PUD ~alt (40% ~trength) 94 42.0
Phenol/~ormaldehyde conde~3ate resin, ~oftening point
(DIN 52,011) 128C 240
Ac~tone III - ¦ 240
Demineralized water l l 1200
The TDI wa~ added to the ~ixture o4 dewatered
polye~terdiol, prepared ~rom adipic acid and 1,4-butane-
diol, acetone I and cataly~t. A~ter a reaction time of
one hour at 65C the HDI wa2 added and the reaction was
continued for a ~urther 90 minute~. After acetone II had
been added, the reaction mixture had an NCO content of
0.75%. At 50C, chain extension wa~ e~focted with P~D
salt, which wa~ present in the 4Orm o~ a 40% ~trength
~olution i~ water. A~ter 5 minute~, th~ re~in ~olution,
prepared from acetone III and a conden~ate o~ phenol and
formaldehyde, was added and ~tirring was carried out for
5 minutes at 50C. Thereaftar, di~paroing wa effected
with water and the acetone wa~ distilled o~. The
di~persion waa brought to a ~olid~ aontent of 40~ by
redilution with d~mineralized water.
EX~MPLES lB AND lC
The disper3ion wa~ prepared ~imilarly to Example
.' ' ' I ' ,' .
21219~9
- 16 - O.Z. ~050/~4008
lA (Comparative Example), except that, after the addition
of the re~in, 8.0 g o~ aluminum (or zirconium) acetyl-
acetonate, dia~olved in 100 ml of acetone, were added.
EXAMPLE 2A (Comparati~e Exa~ple)
Molar amount Part~ by weight
~mmol] ~g]
Polye~terdiol (OH number: 191 476
45.O
1,4-3utanediol 176 14.1
Trimethylolpropane 17.4 2.3
IPDI 436 96.9
DBTL 0.2
Acetone I 133
_ . ...
Acetone II 532
PUD salt (40~ ~tre~gth) I 94 35.0
Phenol/formaldehyde condansate re~i~, 80 tening point
(DIN 52,011) 128C 240
Acetone III ~ ¦ 240
Demineralized watsr 1 1200
The IPDI wa~ added to the mixture of dewatered
polyest2rol, prepared from adipic acid a~d 1,4-butane-
diol, 1,4-buta~adiol, trimethylolpropa~e, acetone I and
catalyet and the reaction waa carried out for 130
minutea. Ater acetone II had been added, the reaction
mixture had an NCO content of 0.57%.
At 50C, chain exten~ion wa~ carried out with PUD
aalt, which wa3 preaent in the for~ of a 40~ ~trength
~olution in water. After 5 mi~utec, the reain solution,
prepared from acetone III and a conde~ate of phenol and
formaldehyde, waa added and ~tirring wa~ carried out for
5 ~inute~ at 50C. Thereafter~ disperaing was effected
with water a~d the acetone was diatilled off. The
. ":., ,: : ~ ::.: ~
-` 21121 ~9 o.z. 0050/44008
disper~ion was then brought to a 301ids content of 40% by
redilution with d~ineralized water.
EX~MPLES 2B AND 2C
The disper~ion was prepared ~imilarly to ~xample
2A (Comparative Example), except that, after the addition
of the resin, 8.0 g of aluminum (or zi~conium) acetyl-
acetonate, di~olved in 100 ml of acetone, were added.
EXAMPLE 3A (Comparative Example)
_Molar amount Parts by weight
~mmol~ ~g]
Polypropylene oxide 298 597
(OH number: 56)
I .
Dimethylolpropionic acid 160 21.5
TDI 867 151
DBTL 0.3 :: :
Acetone 978 :^ :
_ _ :
Demineralized water 1200
30% strength by weight 112 4.5
NaOH solution
. . ' ,~
The TDI wa~ added to the mixture of dewatered
polypropylene oxide, dimethylolpropionic acid and
catalyat and the reaction was carried out at a reaction ~ :~
temperature of 105C for 3 hours. After acetone had been
added, the reaction mixture had an NCO content of O . 45% .
The ~olution was cooled to 30C, after which the
NaOH solution wa~ added and dispersing wa~ effected with
water in ths course of 20 minute~ and tha acetone was
di~tilled off. The dispersion wa3 then brought to a
aolid~ content of 40% by redilution w~th demineralized
water.
EXAMP~ES 3s AND 3C
The disper~ion wa~ prepared 0i~ilarly ~o Example
3A (Comparativo Example), except that, after the addition
of NaO~, 8.0 y of aluminum (or zirconium~ acetyl-
acstonate, di~sol~ed in 100 ml of acetone, were added.
:, : . ,,: ,, .
~ '' :, ' , , : , :
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EXAMPLE 4A (Comparative Example)
The disper ion was prepared ~imilarly to Compara-
tive Example 1. Instead of the phenol/formaldehyde
resin, howe~er, a resin based on phenol and a mixture o~
n-butyraldehyde and i~obutyraldehyde wa~ u~ed (molar
ratio of n-butyraldehyde to isobutyraldehyda = 1 : 1).
The aoftening point (DIN 52,011) wa~ 153C.
EXAMPLES 4B AND 4C
The dispersion wa~ prepared ci~ilarly to Example
4A (Comparative Example), except that, after the addition
of the resin, 8.0 g of aluminum (or zirconium) acetyl-
acetonate, di ~olved in 100 ml o~ acetone, were added.
~,
EXAMPL~ 5A (Com~arative Example) ~
_ . .
Molar amount Parts by weight .
. ~mmoll [g] . ~;
_ _
Polye~terdiol (OH number: 196 489
TDI 159 27.8
_ 159 26.8
DBTL 0.1
Acetone I 133
. .
Ac~tone II ~ l l 532
_
PUD salt (40~ ~trength) 94 42.0
Ph~nol/ i30butyraldehyde condensate resin, ~o~teni~g
poi~t
(DIN 52,011) 132C 240
_ I .
Acetone III ¦ 240
Deminéralized water ¦ 1200
The prsparation was carried out .imilarly to
Example 1, except that the r~action ti~e with XDI wa~
i~crea~ed to ~0 minute3.
.
.
.: . .- . : :
`j 212~9~9
- 19 - O.Z. 0050/44008
EXAMPLES 5~ AND 5C
The di persion wa~ prepared similarly to Example
5A (Comparative Example), exc~pt that, a~ter the addition
o$ the resin, 8.0 g of aluminum (or zirconium) acetyl-
acetonate, di~solved in 100 ml of acetone, wera added.
EXAMPL~ 6A (Comparative Example)
Molar amount Parts by weight
[mmolj _
Polyetherol (OH number: 200 401
56)
Dimethylolpropionic acid 161 21.6
TDI 670 117
DBTL _ _ 0.1
_
I _ --~
Acetone I _ 1 ¦ 684
Phenol/i~obutyraldehyde condensate r~sin, softening : ~
point (DIN 52,011) 128C 240 : ::
_ ~: :
Acetone II _ 240
Demineralized wat~r 1200
__ .
30% ~trength by weight 112 4.5
NaOH solution
The TDI wa~ added to the mixture of dewatersd
polyetherol (polypropylene oxide having an OH ~unctional-
ity of 1.93 equi~alent/mole), dimethylolpropionic acid
and cataly~t, and the reaction wao carried out ~t
reaction temiperature o~ 105C ~or 3 hours. Aft~r acetone
I had been added, the reaction mixtura had an NCO content
o~ 0.56~.
A~t~r neutralization with the NaO~ 301ution, the
resin solution, pr~pared from acetone II and a conden~ate
of phonol and a mixture o~ n-butyxaldehyde and i80-
butyraldehyde (molar ratio 1 : 1), wa~ added. The
solution wa~ cooled to 30C, after whi~h disper~ing wa~
: : :: ~: I
, :: -: : . :: :
: :.. ::. . ,:, , : : : -,
2~2~59
- 20 - O.Z. 0050/44008
effected with water in the cour~e o~ ~0 minutes and the
acetone wa~ di~tilled of~. The dispersion wa~ then : -
brought to a solid~ content of 40% by redilutio~ wtih
demineralized water. ~ .-
-
EXAMPLES 6~ AND 6C
The disper~ion wa~ prepared ~imilarly to Example
6A (Comparative Example), except that, after the addition
of the resin, 8.0 g of aluminum (or zirconium) acetyl-
acetonate, dis~olved in 100 ml o~ acetone, were added. ~ :
Contact adhasive bonding at room temperature
Sample preparation:
The disper~ion~ were thickened with 5% by weight,
ba~ed on it~ ~olid, of pyroge~ic ailica.
Shear ~trength~
The particular di~persion~ were applied to beech
wood panel~ over an area of 150 x 50 mm2 with a knifa : :~
coater having 1 mm teeth and were dried ~or 60 mi~ute~ at
room te~erature. The~e te~t ~pecimen5 were then
immediately adhe~ively bonded by pre~ing them for 30 ;~
~econds at room temperature under a pressure of
O.5 N/m~2 . The ~hear ~trength wa~ mea~ured immediately
(inatantaneou~ ~trength) and after 3torage ~or 7 day~ at `~
room temperature (final ~tre~gth), in N/~ma. :~
Heat di~tortion re~istance:
A har~board wa~ adhe~ively bonded with a PVC ~ilm
over an area o~ 200 x 200 mm3 (contact adhe~ive bonding
at room temperature). ~he PVC film was ~ubjected to a
load of 300 g at a peeli~g angle of 180. The
temperature wa~ increased by 10C e~ery 30 minutes. The
max$mum temperaturo at which the PVC film i3 ~till not
completely detached ~rom the hardboard i~ ~tatsd.
.. . . . .- .... - . . . . .................... ~ .
-: ... ,,, " . ~; , . . i ~ . -
` 2~219~9
- 21 - O.Z. 0050/44008
EXAMP~S 6B AND ~C
The di~per~ion waa prepared ~imilarly ~o Example
6A (Comparative Example), except that, after the additlon
o~ the resin, 8.0 g of aluminum (or zirconium) acetyl-
acetonate, dis~olved in 100 ~1 of acetone, were added.
Contact adheaive bondins at room temperature
Sample preparation:
The dispersions were thickened with 5% by weight,
- based on it~ solid, of pyrogenic silica.
Shear strength:
The particular dispersions were applied to baech
wood panal~ ov~r an area of 150 x 50 mml with a knife
coater having 1 mm teeth and were dried for 60 minutes at
room temperature. These t98t specimens were then
immediately adhesively bonded by preR~ing them for 30
seconds at room t~mperature undor a pressure of
0.5 N/mm2. The shear strength wa~ mea~ured immedia~ely
(instanta~eous ~trength) and after storage for 7 day~ at
room temperature (final ~trength), i~ N/mm2.
~eat di~tortion resi~tance~
A hardboard was adhe~i~ely bondad wit~ a PVC film
over an area o_ 200 x 200 ~m~ (co~tact adhesive bonding
at room temperature~. The PVC 4ilm wa~ ~ubjected to a
load of 300 g at a peeling angle of 180. The
tamperature wa~ increased by 10C every 30 minute~. The
maximum temperature at which the PVC film i ~till not
completely detached ~rom the hardboard i8 ~tated.
21219~i9
..
, ~
- 22 - O . Z . 0050/44008
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Te~ting of the contact adheaive bond af ter flash activa-
tion (heat actiYation)
Sample preparation:
The diaper~on~ were thickened with 2% by weight,
based on their solid, of polyvinylpyrrolidone.
Peel strength:
The di~persion3 were applied with a brush (1
inch, ~ine bristles) uniformly to styrene/butadiene
rubber (SBR1 rubber having a Shore A hardne3s of 90 (cf.
lC DIN 16,909)) over an area of 30 x 130 mm2 and were dried
for 45 minute~ at room t~mperature. After the adhe~ive
~ilms had been heated once by IR radiation to 80C in the
cour~ o$ about 5 ~econds (flash activation), the samples
were pre3eed for 10 second~ at 0.5 N/mm2. The peel
strength was measured immediately (in~tantaneous
strength) and after storage for 5 day~ in a conditioned
chamber (23C/50% relativ0 humidity3 (final ~trength),
according to DIN 52,273.
Heat distortion re~i~tance:
The te~t ~pecimen~ were produced a3 for testing
of the peel strength. After being heated for 1 hour at
50C, they were loaded, at 50C, with 5, 10, 15, 20, 25
and 30 N in a~canding order, for 10 minute~ in each ca3e.
If the adhQsive bond held, the load waQ r~moved from the
sample and tha sample wae heated to 60C for 30 minute~
and te~ted again up to 30 N in 10 minute step~. After
each cycle, the test temperaturs wa3 i~crea~ed by 10C.
The temperature (C) and the load (N) at which breaki~g
of the adhesive bond by more than 50 mm wae det~ctable
are stated in each ca~e.
21219~9
24 - O.Z. 0050/44008
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