Gap-Filling Cyanoacrylate Adhesive
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Gap-filling cyanoacrylate adhesives containing cyanoacrylate esters and organic halogenated polymers with a K-value of at least 46.
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(19) United States
US 2006024l226Al
(12) Patent Application Publication (10) Pub. No.: US 2006/0241226 A1
Bachon et al.
(43) Pub. Date: Oct. 26, 2006
(54) GAP-FILLING CYANOACRYLATE
ADHESIVE
(75) Inventors: Thomas Bachon, Duesseldorf (DE);
Horst Beck, Neuss (DE); Jennifer
Lambertz, Langenfeld (DE); Bernd
Beuer, Monheim (DE)
Correspondence Address:
HENKEL CORPORATION
THE TRIAD, SUITE 200
2200 RENAISSANCE BLVD.
GULPH MILLS, PA 19406 (US)
(73) Assignee: Henkel Kommanditgesellschaft auf
Aktien (Henkel KGaA), Duesseldorf
(DE)
(21) Appl. No.: 11/427,424
(22) Filed: Jun. 29, 2006
Related U.S. Application Data
(63) Continuation of application No. PCT/EP05/00070,
filed on Jan. 7, 2005.
(30) Foreign Application Priority Data
Jan. 9, 2004 (DE) ........................ .. 10 2004 001 493.0
Publication Classification
(51) Int. Cl.
C08K 5/10 (2006.01)
(52) U.S.Cl. ............................................................ ..524/315
(57) ABSTRACT
Gap-filling cyanoacrylate adhesives containing cyanoacry-
late esters and organic halogenated polymers with a K-Value
of at least 46.
US 2006/0241226 Al
GAP-FILLING CYANOACRYLATE ADHESIVE
CROSS REFERENCE TO RELATED
APPLICATIONS
[0001] This application is a continuation under 35 U.S.C.
§ 365(c) and 35 U.S.C. § 120 of international application
PCT/EP 2005/000070, filed on Jan. 1, 2005. This application
also claims priority under 35 U.S.C. § 119 of DE 10 2004
001 493.0, filed Jan. 9, 2004, which is incorporated herein
by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a gap-filling cyanoacrylate
adhesive. Cyanoacrylate adhesives have basically been
known for a long time. Cyanoacrylate adhesives are one-
component reactive adhesives based on monomeric esters of
2-cyanoacrylic acid. They have conquered the market by
their extremely fast curing, which only requires a few
seconds according to the substrate. The resulting properties
meet many requirements set forth in industrial practice.
Nevertheless they need to be further improved in special
cases of application.
[0003] In particular, the fact that cyanoacrylate adhesives
hitherto could not be applied for making gap-filling bonds,
has strongly reduced the field of application of these adhe-
sives which are otherwise very appreciated. Hitherto,
cyanoacrylate adhesives could only be applied mainly in
cases in which the surfaces of the substrate to be adhered,
could essentially be adhered without any gaps.
[0004] Compositions are known from the state of the art,
which describe the rheological influence of cyanoacrylate
esters by addition of ester soluble polymers. Hence, for
example, a composition is described in U.S. Pat. No. 4,477,
607, which contains a cyanoacrylate ester, a small amount of
a dissolved organic polymer and silica gel. The document
does not give any indication about the organic polymers
used, and their properties with regard to the required
molecular weights,
[0005] U.S. Pat. No. 3,223,083 relates to the use of
cyanoacrylate esters thickened with organic polymers for
bonding body tissues, for example for bonding bones. For
this purpose, by means of an application exhibiting two
chambers, a mixture of one cyanoacrylate ester thickened
with an organic polymer on the one hand and a protein
dissolved in water on the other hand, are introduced into the
area to be adhered.
[0006] German Patent DE 34 00 577 C2 relates to
cyanoacrylate adhesives which exhibit a relatively small
adhesivity to the skin. Suitable cyanoacrylate adhesives for
this purpose contain a vinyl chloride/vinyl acetate copoly-
mer, which comprises not less than 5% by weight of vinyl
acetate and at the best should have a molecular weight of at
least 8,000, there is a problem in the described composition
in that the gap-filling properties are only badly developed
because of the amount of vinyl acetate. Furthermore, it is
shown that resistance to hydrolysis of the thereby obtained
bonds leaves much to be desired.
[0007] WO 99/28399 relates to a cyanoacrylate adhesive
with an ester addition, wherein at least partial and/or com-
plete esters of monovalent or polyvalent aliphatic carboxylic
acids are used as esters. The document actually mentions the
Oct. 26, 2006
addition of different polymers; however no indication is
given as to their potential for influencing the gap-filling
properties.
[0008] Accordingly, the object of the present invention
consisted in avoiding the drawbacks of the known
cyanoacrylate adhesives as regards the lacking gap-filling
properties. Specifically, the object according to the invention
consisted in preparing a cyanoacrylate adhesive with good
storage stability, useful strengths and a practically
unchanged setting rate, which additionally is in a position to
enable gap-filling bondings and furthermore still exhibits
excellent stability to hydrolysis.
DESCRIPTION OF THE INVENTION
[0009] Now, it has been found that adding halogenated
polymers with a K value of more than 46 significantly
enhances the gap-filling properties of a cyanoacrylate adhe-
sive.
[0010] Accordingly, the objects at the basis of the inven-
tion are achieved by compositions which contain at least one
cyanoacrylate ester and at least one halogen-containing
organic polymer with a K value of more than 46.
[0011] Accordingly, the object of the present invention is
an adhesive, containing at least 50% by weight of a
cyanoacrylate ester or a mixture of two or more cyanoacry-
late esters and 5 to 15% by weight of at least one haloge-
nated polymer with a K value of at least about 46.
[0012] Cyanoacrylate adhesives are essentially based on
monoacrylic acid esters and/or bis-cyanoacrylates. By
“monocyanoacrylic acid esters”, are meant compounds of
general formula I
H2C:C(CN)—CO—O—R (1)
wherein R represents a C1-C24 alkyl, alkenyl, C1-C24
cycloalkyl, aryl, alkoxyalkyl, aralkyl, or haloalkyl, in par-
ticular a methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-
butyl, pentyl, hexyl, allyl, methallyl, crotyl, propargyl,
cyclohexyl, benzyl, phenyl, cresyl, 2-chloroethyl, 3-chloro-
propyl, 2-chlorobutyl, trifluoroethyl, 2-methoxyethyl,
3-methoxyethyl, and 2-ethoxyethyl.
[0013] The aforementioned cyanoacrylates are known to
one skilled in the art of adhesives. On this matter, reference
is made explicitly to Ullmarm’s Encyclopaedia of Industrial
Chemistry, vol. Al, pp. 240, Verlag Chemie Weinheim
(1985) as well as to U.S. Pat. Nos. 3,254,111-A and 3,654,
340-A as regards to the corresponding details, wherein the
disclosure of the cited documents concerning cyanoacrylate
esters and adhesives made therefrom, is understood as being
part of the disclosure of the present text.
[0014] Preferred monomers are the allyl, methoxyethyl,
ethoxyethyl, methyl, ethyl, propyl, isopropyl, or butyl esters
of 2-cyanoacrylic acid.
[0015] By “biscyanoacrylates” are meant substances of
general formula II
[H2C:C(CN)—CO—O]2—R1 (11)
wherein R1 represents a branched or unbranched, at least
bivalent, alkylene with 2 to 18, in particular 6 to 12 C atoms,
which may also even contain heteroatoms such as halogens
and oxygen, or aliphatic or aromatic rings. However, R1
preferably represents a pure hydrocarbon.
US 2006/0241226 A1
[0016] It is preferred that the biscyanoacrylates be par-
ticularly pure for use as part of an adhesive formulation. For
example, biscyanoacrylates with suitable purity may be
obtained by the following preparation and purification meth-
ods: for example, monocyanoacrylates are transesterified
with diols and then the reaction mixtures are treated by
fractional crystallization.
[0017] An appropriate method for making biscyanoacry-
lates therefore consists of transesterifying 2-cyanoacylic
acid or its alkyl ester of general formula III
H2C:C(CN)—CO—O—R2 (111)
wherein R2 represents a branched or unbranched alkyl with
l to 6 C atoms, with diols of general formula IV
[H0]2*R1 (IV)
wherein R1 represents a branched or unbranched bivalent
alkylene with 2 to 18 C atoms, which may also even contain
heteroatoms such as halogens and oxygen, or aliphatic or
aromatic rings, into biscyanoacrylates of general formula II
and then purifying the reaction mixture by fractional crys-
tallization.
[0018] A starting product is therefore the monofunctional
cyanoacrylic acid or its alkyl esters according to formula III.
The alkyl should be selected if possible so that the formed
alcohol may be removed easily. The possibilities suitable for
this are known to one skilled in the art from the general
transesterification reaction. Preferably, the alcohol is dis-
tilled olf. Consequently, R2 preferably represents a linear or
branched alcohol with l to 6 C atoms, preferably with l to
2 C atoms. The monofunctional cyanoacrylic acid ester is
generally stabilized in the usual way for example.
[0019] As for the diols (formula IV), they are bivalent
primary or secondary alcohols, preferably primary alcohols.
The hydroxyl groups may be positioned essentially in any
manner, however they are preferably found at the ends on
the hydrocarbon chain. The diols have 2 to 18 C atoms,
preferably 6 to 12 C atoms. They may have a linear,
branched or cyclic configuration. The aliphatic radical may
also contain an aromatic group or even heteroatoms, such as
for example chlorine or oxygen atoms, in addition to the
hydrogen and carbon atoms, preferably in the form of
polyethylene glycol and polypropylene glycol units. Let us
mention as specific diols: hexanediol, octanediol, decanediol
and dodecanediol.
[0020] The cyanoacrylic acid ester is preferably applied in
excess. The molar ratio of monofunctional cyanoacrylic acid
ester to diol for example, is at least 2.0:l.0, but preferably
2.5:l.0, in particular 2.2:l.0.
[0021] Transesterification is catalyzed by strong acids, in
particular by sulfonic acids, preferably by aromatic sulfonic
acids, such as, for example, p-toluenesulfonic acid. But
naphthalenesulfonic acid and benzenesulfonic acid as well
as acid ion exchangers are also possible. The concentration
of the transesterification catalyst should be between 1 and
20% by weight, based upon the monofunctional cyanoacry-
late.
[0022] Transesterification preferably occurs in solution.
Aromatic substances and halohydrocarbons are used as
solvents. The preferred solvents are toluene and xylene. The
concentration of the solution is in the range from 10 to 50,
preferably from 10 to 20%.
Oct. 26, 2006
[0023] The formed monovalent alcohol or the formed
water are removed in a known way, preferably by distillation
with the solvent. The yield of the transesterification is
controlled by means of NMR spectra for example. The
reaction may run over a period of a few minutes to several
hours. In the case of toluene as solvent and p-toluenesulfonic
acid as catalyst, the reaction is for example completed after
10 to 15 hours, i.e. alcohol is no longer separated.
[0024] In the case of acid ion exchangers as catalyst, the
latter can simply be filtered out for treating the reaction
mixture. In the case of soluble sulfonic acids as catalyst, for
example in the case of p-toluenesulfonic acid, the latter is
separated by substituting the solvent: toluene is replaced
with a mixture of hexane, heptane or decane. Pure biscy-
anoacrylate is obtained after two fractional crystallizations.
Purity according to NMR spectra is higher than 99%.
[0025] The obtained biscyanoacrylate is storage-stable
with the usual stabilizers and in the usual concentrations,
i.e., its melting point does not change at 20° C. within a 6
month period, in practice.
[0026] The obtained biscyanoacrylates however polymer-
ize in the presence of bases very rapidly, preferably practi-
cally as rapidly as the corresponding monocyanoacrylates.
As in the case of monofunctional cyanoacrylates, traces of
water are already sufficient. A three-dimensional cross-
linked polymer with good thermal properties forms subse-
quently. An adhesive according to the invention, in addition
to a cyanoacrylate ester or a mixture of two or more
cyanoacrylate esters, further contains at least one halogen-
containing organic polymer.
[0027] Examples of such halogen-containing polymers are
polymers of vinyl chloride, vinyl resins, which contain vinyl
chloride units in the polymer backbone, copolymers of vinyl
chloride and esters of acrylic and methacrylic acid or acry-
lonitrile or mixtures of two or more thereof, copolymers of
vinyl chloride with diene compounds or unsaturated dicar-
boxylic acids or their ar1hydrides, for example copolymers
of vinyl chloride with diethyl maleate, diethyl fumarate, or
maleic acid anhydrides, post-chlorinated polymers and
copolymers of vinyl chloride, copolymers of vinyl chloride
and vinylidene chloride with unsaturated aldehydes,
ketones, and other compounds such as acrolein, crotonalde-
hyde, vinyl methyl ketone, vinyl methyl ether, vinyl isobutyl
ether and the like, polymers and copolymers of vinylidene
chloride with vinyl chloride and other polymerizable com-
pounds, as those already mentioned above, polymers of
vinyl chloroacetate, and dichlorodivinyl ethers, chlorinated
polymers of vinyl acetate, chlorinated polymer esters of
acrylic acid, and ot-substituted acrylic acids, chlorinated
polystyrenes, for example polydichlorostyrene, chlorinated
polymers of ethylene, polymers and post-chlorinated poly-
mers of chlorobutadiene and their copolymers with vinyl
chloride, as well as mixtures of two or more of the cited
polymers or polymer mixtures, which contain one or more
of the aforementioned polymers.
[0028] Within the scope of the present invention, it is
required that corresponding halogen-containing polymers
have a K value (according to Fikentscher) of at least about
46, preferably of at least about 48. It is more preferred
according to the invention that the K value be from about 49
to about 62, in particular from about 50 to about 58.
[0029] Further, according to the invention, it is possible to
apply a mixture of halogen-containing polymers which have
US 2006/0241226 A1
different K values. A mixture of halogen-containing poly-
mers is also suitable, in which the K value above differs by
at least about 2, preferably by at least 3 or more, for example
by at least about 4, 5, 6, 7 or 8.
[0030] Within the scope of a more preferred embodiment
of the present invention, an adhesive according to the
invention contains as an organic halogen-containing poly-
mer, polyvinyl chloride (PVC) with a K value from about 50
to about 58. Mixtures of polyvinyl chloride with different K
values, in particular a mixture of polyvinyl chloride with a
K value of about 50 and of a polyvinyl chloride with a K
value of about 58, are also suitable.
[0031] An adhesive according to the invention contains
about 50 to about 99% by weight of cyanoacrylate ester and
more than 5% by weight to about 35% by weight of organic
halogen-containing polymers, wherein the content of
organic halogen-contaimng polymers with the required K
value according to the invention is within the limits men-
tioned within the scope of the present text.
[0032] In addition to the aforementioned components,
cyanoacrylate ester and organic halogen-containing poly-
mers, an adhesive according to the invention may addition-
ally contain further additives, for example softeners, thick-
eners, stabilizers, activators, dyes, and accelerators, for
example polyethylene glycol, or cyclodextrin.
[0033] Particular ester compounds are suitable as plasti-
cizers. As for the alcohol component of the ester, these are
preferably alcohols with 1 to 5, in particular 2 to 4 OH
groups and with 2 to 5, in particular 3 or 4 C atoms, directly
bound to each other.
[0034] The number of C atoms not directly bound to each
other may amount to 110, in particular up to 18 C atoms.
[0035] As exemplary monovalent alcohols, let us mention:
methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-bu-
tanol, 2,2-dimethyl-1-propanol, 2-methyl-1-propanol, 2,2-
dimethyl-1-propanol, 2-methyl-2-propanol, 2-methyl-l-bu-
tanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-
butanol, 1-pentanol, 2-pentanol, 3-pentanol, cyclopentanol,
cyclopentenol, glycidol, tetrahydrofurfurylic alcohol, tet-
rahydro-2H-pyran-4-ol, 2-methyl-3-buten-2-ol, 3-methyl-2-
buten-2-ol, 3-methyl-3-buten-2-ol, 1-cyclopropyl-ethanol,
l-penten-3-ol, 3-penten-2-ol, 4-penten-l-ol, 4-penten-2-ol,
3-pentyn-l-ol, 4-pentyn-l-ol, propargylic alcohol, allylic
alcohol, hydroxyacetone, 2-methyl-3-butyn-2-ol.
[0036] As exemplary bivalent alcohols, let us mention:
1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, dihy-
droxyacetone, thioglycerine, 2-methyl-1,3-propanediol,
2-butyne-1,4-diol, 3-butene-1,2-diol, 2,3-butenediol, 1,4-
butenediol, 1,3-butenediol, 1,2-butenediol, 2-butene-1,4-
diol, 1,2-cyclopentanediol, 3-methyl-1,3-butenediol, 2,2-
dimethyl-1,3-propanediol, 4-cyclopentane-1,3-diol, 1,2-
cyclopentenediol, 2,2-dimethyl-1,3 -propanediol, 1,2-
pentenediol, 2,4-pentenediol, 1,5 -pentenediol,
4-cyclopentene-1,3-diol, 2-methylene-1,3-propanediol, 2,3-
dihydroxy-1,4-dioxane, 2,5-dihydroxy-1,4-dithiane.
[0037] As exemplary trivalent alcohols, let us mention:
glycerine, erythrulose, 1,2,4-butanetriol, erythrose, threose,
trimethylolethane, trimethylolpropane, and 2-hydroxym-
ethyl-1 ,3 -propanediol.
Oct. 26, 2006
[0038] As exemplary quadrivalent alcohols, let us men-
tion: erythritol, threitol, pentaerythritol, arabinose, ribose,
xylose, ribulose, xylulose, lyxose, ascorbic acid, gluconic
acid y-lactone.
[0039] As exemplary pentavalent alcohols, let us mention:
arabitol, adonitol, xylitol.
[0040] The polyvalent alcohols described above may also
be applied in an ether form for example. The ethers may for
example be produced by condensation reactions, William-
son’s ether synthesis or by conversion with alkylene oxides
such as ethylene oxide, propylene oxide or butylene oxide
from the aforementioned alcohols. As examples, let us
mention: diethylene glycol, triethylene glycol, polyethylene
glycol, diglycerine, triglycerine, tetraglycerine, pentaglyc-
erine, polyglycerine, technical mixtures of condensation
products of glycerine, glycerine propoxylate, diglycerine
propoxylate, pentaerythritol ethoxylate, dipentaerythritol,
ethylene glycol monobutyl ether, propylene glycol mono-
hexyl ether, butyldiglycol, dipropylene glycol monomethyl
ether.
[0041] As monovalent carboxylic acids for esterification
with the aforementioned alcohols, let us mention: formic
acid, acrylic acid, acetic acid, propionic acid, butyric acid,
isobutyric acid, valeric acid, isovaleric acid, 2-oxovaleric
acid, 3-oxovaleric acid, pivalic acid, acetacetic acid, levulic
acid, 3-methyl-2-oxobutyric acid, propiolic acid, tetrahydro-
furane-2-carboxylic acid, methoxyacetic acid, dimethoxy-
acetic acid, 2-(2-methoxyethoxy)acetic acid, 2-methylacetic
acid, pyruvic acid, 2-methoxyethanol, vinylacetic acid, ally-
lacetic acid, 2-pentenic acid, 3-pentenic acid, tetrahydro-
furane-2-carboxylic acid.
[0042] As examples of polyvalent carboxylic acids let us
mention: oxalic acid, malonic acid, fumaric acid, maleic
acid, succinic acid, glutaric acid, acetylene-dicarboxylic
acid, oxalacetic acid, acetone-dicarboxylic acid, mesoxalic
acid, citraconic acid, dimethylmalonic acid, methylmalonic
acid, ethylmalomc acid.
[0043] Hydroxycarboxylic acids may also be used as
starting materials, for example tartronic acid, lactic acid,
malic acid, tartaric acid, citramalic acid, 2-hydroxyvaleric
acid, 3-hydroxyvaleric acid, 3-hydroxybutyric acid, 3-hy-
droxyglucaric acid, dihydroxyfumaric acid, 2,2-dimethyl-3-
hydroxypropionic acid, dimethylolpropionic acid, glycolic
acid.
[0044] Esterification may occur either completely or par-
tially. If necessary, mixtures of these acids may also be used
for the esterification.
[0045] The esters to be used according to the invention,
produced from these alcohols and carboxylic acids or from
the corresponding derivatives preferably are free of cata-
lysts, in particular of alkali metals and amines. This can be
achieved by treating the esters according to the invention
with acids, ion exchangers, acetic aluminas, aluminium
oxides, active charcoals, or other adjuvants known to one
skilled in the art. For drying them and further purification,
they may be distilled.
[0046] As exemplary esters particularly suitable as plas-
ticizers, let us mention: ethyl acetate, butyl acetate, glycerine
triacetate, glycerine tripropionate, triglycerine pentaacetate,
polyglycerine acetate, diethylene glycol diacetate, 3-hy-
US 2006/0241226 Al
droxyvaleric acid ethyl ester, lactic acid butyl ester, lactic
acid isobutyl ester, 3-hydroxybutyric acid ethyl ester, oxalic
acid diethyl ester, mesoxalic acid diethyl ester, malic acid
dimethyl ester, malic acid diisopropyl ester, tartaric acid
diethyl ester, tartaric acid dipropyl ester, tartaric acid diiso-
propyl ester, glutaric acid dimethyl ester, succinic acid
dimethyl ester, succinic acid diethyl ester, malic acid diethyl
ester, fumaric acid diethyl ester, malonic acid diethyl ester,
acrylic acid 2-hydroxyethyl ester, 3-oxovaleric acid methyl
ester, glycerine diacetate, glycerine tributyrate, glycerine
tripropionate, glycerine dipropionate, glycerine triisobu-
tyrate, glycerine diisobutyrate, glycidyl butyrate, acetic acid
butyl ester, levulic acid ethyl ester, 3-hydroxyglutaric acid
dimethyl ester, glycerine acetate dipropionate, glycerine
diacetate butyrate, propiolic acid butyl ester, propylene
glycol diacetate, propylene glycol dibutyrate, diethylene
glycol dibutyrate, trimethylolethane triacetate, trimethylol-
propane triacetate, trimethylolethane tributyrate, neopen-
tylic alcohol dibutyrate, methoxyacetic acid pentyl ester,
dimethoxy acetic acid butyl ester, glycolic acid butyl ester.
[0047] The mentioned esters are added in an amount up to
50% by weight, preferably in an amount from 1 to 30% by
weight, based on the total adhesive. The polycyanoacrylates
starting from a concentration of 30, in particular 40% by
weight, exhibit tacky properties.
[0048] Further suitable plasticizers are for example esters
such as abietic acid esters, adipic acid esters, azelaic acid
esters, benzoic acid esters, butyric acid esters, acetic acid
esters, esters of higher fatty acids with about 8 to about 44
C atoms, esters of epoxidized or OH group bearing fatty
acids, fatty acid esters and fats, glycolic acid esters, phos-
phoric acid esters, phthalic acid esters of linear or branched
alcohols containing 1 to 12 C atoms, propionic acid esters,
sebacic acid esters, sulfonic acid esters, thiobutyric acid
esters, trimellitic acid esters, citric acid esters, as well as
mixtures of two or more thereof. The asymmetric esters of
difunctional, aliphatic or aromatic dicarboxylic acids are
particularly suitable, for example the esterification product
of adipic acid monooctyl ester with 2-ethylhexanol (Edenol
DOA, Cognis, Duesseldorf) or the esterification product of
phthalic acid with butanol.
[0049] The pure or mixed ethers of monofunctional, linear
or branched C4-C16 alcohols or mixtures of two or more
different ethers of such alcohols, for example dioctyl ether
(available as Cetiol OE, Cognis, Duesseldort) are also
suitable as plasticizers.
[0050] Polyethylene glycols with closed terminal groups
are also suitably used, for example polyethylene or polypro-
pylene glycol di-(C1-C4-alkyl) ethers, in particular dimethyl
or diethyl ethers of diethylene glycol or dipropylene glycol,
as well as mixtures of two or more thereof.
[0051] Basically all materials are suitable as fillers, those
which on the one hand fill the adhesive and on the other hand
do not adversely influence or no more than is unavoidable,
the adhesive properties of the adhesive. Silica gels are
particularly suitable as fillers, in particular surface-treated
silica gels. For example, suitable fillers are described in U.S.
Pat. No. 4,477,607. The disclosure of this document with
regards to fillers in adhesives with a content of cyanoacry-
late esters is considered as part of the disclosure of the
present text.
Oct. 26, 2006
[0052] Further suitable fillers are for example glass pow-
der, glass flour, glass hollow beads or glass fibres as well as
other suitable inorganic fillers known to one skilled in the
art.
[0053] The filler content may basically be selected essen-
tially in any way, as long as the effect according to the
invention is not influenced by the filler content. However,
filler contents in a range from about 5 to about 30 or about
10 to about 20% by weight, based on the total adhesive, are
particularly suitable.
[0054] Basically, all compounds currently applied for
thickening solutions with a cyanoacrylate ester content may
be used as thickeners, as long as they do not adversely
influence or no more than is unavoidable, the gap-filling
properties of the adhesive according to the invention. The
content of an adhesive according to the invention in such
thickeners may for example be from 0 to about 10 or from
about 2 to about 5% by weight.
[0055] Within the scope of the present invention, all
compounds applied currently for stabilizing cyanoacrylate
esters against radical polymerization are suitable as stabi-
lizers especially radical scavengers based on phenol such as
hydroquinone. The content of an adhesive according to the
invention in such stabilizers preferably is from about 0 to
about 3% by weight, based on the total adhesive.
[0056] Within the scope of the present invention, all
compounds applied currently for colouring compositions
containing cyanoacrylate esters are suitable as dyes, insofar
that the latter do not adversely influence or no more than is
unavoidable the curing of the adhesive and its gap-filling
properties.
[0057] In particular, compounds which accelerate the cur-
ing of the adhesive without adversely influencing or no more
than is unavoidable, its adhesive properties or its gap-filling
properties, are suitable as accelerators. The content of an
adhesive according to the invention in such accelerators
preferably is from about 0 to about 5% by weight, based on
the total adhesive.
[0058] The adhesive is made as usual by mixing the
component. The storage stability of the new adhesives was
more than 1 year at room temperature or more than 10 days
at 80° C. in all the investigated cases.
[0059] The viscosity of an adhesive according to the
invention preferably is within a range from about 500 to
about 25,000 mPa.s (as measured with a Brookfield RVT,
23° C., spindle 7, 2.5 rpm).
[0060] The curing rate is practically uninfluenced by the
organic halogen-containing polymers applied according to
the invention, i.e., it is preferably not doubled and does not
practically exceed 1 min.
[0061] The new cyanoacrylate adhesive according to the
invention is particularly suitable for bonds especially of
rubber, metals, wood, ceramic, china, cardboard, paper,
cork, and plastics, except PE, PP and Teflon and Styropore.
[0062] As used herein, and in particular as used herein to
define the elements of the claims that follow, the articles “a”
and “an” are synonymous and used interchangeably with “at
least one” or “one or more,” disclosing or encompassing
both the singular and the plural, unless specifically defined
US 2006/0241226 A1
otherwise. The conjunction “or” is used herein in its inclu-
sive disjunctive sense, such that phrases formed by terms
conjoined by “or” disclose or encompass each term alone as
well as any combination of terms so conjoined, unless
specifically defined otherwise. All numerical quantities are
understood to be modified by the word “about,” unless
specifically modified otherwise or unless an exact amount is
needed to define the invention over the prior art.
[0063] The invention is now explained in detail with the
help of examples:
EXAMPLES
[0064] In order to obtain an overview as complete as
possible, on the properties of the adhesives according to the
invention, mixtures of basically stabilized pure esters and
different polymers were made. Further, ethyl cyanoacrylate
was heated to 80° C. with moisture excluded and mixed with
different organic polymers. The polymers were dissolved or
gelified for 10-20 minutes at 80-100° C.
[0065] PVC-PVC bonds with a gap (0.6 mm) or without
any gap, were made with the cyanoacrylate polymer mix-
tures. The combined tension and shear resistances were
determined after 7 days of storage.
[0066] In addition, wood-wood bonds with a gap (0.4 mm)
and without any gap, were made with the cyanoacrylate
polymer mixtures. The bonds were stored for 24 h, and then
boiled for 6 h in water, and the combined tension and shear
resistances were determined after further 2 h storage in cold
water.
[0067] The results are summarized in the following table:
PVC PVC Wood Wood
(0 mm) (0.6 mm) (0 mm) (0.6 mm)
N°: Mixture; (N/mm2) (N/mm2) (N/mm2) (N/mm2)
1 Ethyl CA 6.5 0 6.8* 0
2 Ethyl CA + PVAC 6.6 2.6 7.8 0
(9%)
3 Ethyl CA + PVC(K 14.2 4.4 8.0 4.4
value = 50) (9%)
4 Ethyl CA + PVC(K 7.1 3.4 7.5 4.1
value = 50)
(4.5%) + PVC (K
value = 58) (4.5%)
5 Ethyl CA + PVC(K 10.5 8.9 7.1 2.7
value = 58) (9%)
[0068] Conclusions/Explanations
[0069] Pure CA does not have any gap-filling properties
(Example 1).
[0070] CA is thickened by PVAC and delivers moderately
good resistances, but is rapidly hydrolyzed in the gap
(Example 2).
[0071] PVC interacts with CA by filling the gap and even
after treatment with boiling water provides sufficient resis-
tances.
[0072] Making of an Adhesive Formulation
[0073] 75 g of ethyl cyanoacrylate were mixed with 15 g
of PVC powder (K value=50) and heated without stirring
with air excluded. The warm mixture was stirred for 10
Oct. 26, 2006
minutes with air excluded and then mixed with 2 g of
hydrophobicized silicic acid and further stirred for 5 min-
utes.
[0074] Wood-wood bonds were made with the adhesive
and the following properties were determined.
Heat resistance Watt 91 at 80° C. 10.55 N/mm2 100% HB
Dry adhesivity EN 204 D1 12.08 N/mm2 100% HB
Wet adhesivity EN 204 D3 7.52 N/m2 100% HB
Wet ad.hesivity EN 204 D4 6.37 N/mm2 KB
[0075] Various substrates were adhered together with the
adhesive and the combined tension and shear resistances
were determined after 2 days of storage:
PVC—PVC 7.1 N/mm2
Birch wood-birch wood 7.5 N/mm2
PMMA—PMMA 5.5 N/mm2
Aluminium-aluminium 4.6 N/mm2
Brass-brass 6.0 N/mm2
[0076] PVC tubes were adhered with the adhesive by
means of a fitting et service life investigations were per-
formed at room temperature and at a hydrostatic pressure of
50 bars. The adhesives outlasted the test period of more than
1,000 hours, undamaged.
What is claimed is:
1. An adhesive, comprising at least 50 weight % of one or
more cyanoacrylate esters and 5 to 15 weight % of at least
one halogenated polymer having a K-value of at least about
46.
2. The adhesive of claim 1, comprising 60 to 95 weight %
of the one or more cyanoacrylate esters.
3. The adhesive of claim 2, comprising 7 to 12 weight %
of at least one halogenated polymer with a K-value of at
least about 46.
4. The adhesive of claim 3, comprising at least one
organic halogen-containing polymer with a K-value of at
least 50.
5. The adhesive of claim 4, comprising at least one
organic halogen-containing polymer with a K-value of
maximum 58.
6. The adhesive of claim 1, comprising a filler.
7. The adhesive of claim 1, wherein the cyanoacrylate
esters comprise one or more of ethyl cyanoacrylate, butyl
cyanoacrylate or methoxyethyl cyanoacrylate.
8. The adhesive of claim 1, comprising 7 to 12 weight %
of at least one halogenated polymer with a K-value of at
least about 46.
9. The adhesive of claim 1, comprising at least one
organic halogen-containing polymer with a K-value of at
least 50.
10. The adhesive of claim 2, comprising at least one
organic halogen-containing polymer with a K-value of at
least 50.
11. The adhesive of claim 1, comprising at least one
organic halogen-containing polymer with a K-value of
maximum 58.
US 2006/0241226 Al
12. The adhesive of claim 2, comprising at least one
organic halogen-containing polymer with a K-value of
maximum 58.
13. The adhesive of claim 3, comprising at least one
organic halogen-containing polymer with a K-value of
maximum 58.
14. The adhesive of claim 2, wherein the cyanoacrylate
esters comprise one or more of ethyl cyanoacrylate, butyl
cyanoacrylate or methoxyethyl cyanoacrylate.
Oct. 26, 2006
15. The adhesive of claim 3, wherein the cyanoacrylate
esters comprise one or more of ethyl cyanoacrylate, butyl
cyanoacrylate or methoxyethyl cyanoacrylate.
16. The adhesive of claim 4, wherein the cyanoacrylate
esters comprise one or more of ethyl cyanoacrylate, butyl
cyanoacrylate or methoxyethyl cyanoacrylate.
17. The adhesive of claim 5, wherein the cyanoacrylate
esters comprise one or more of ethyl cyanoacrylate, butyl
cyanoacrylate or methoxyethyl cyanoacrylate.
* * * * *
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