Note: Descriptions are shown in the official language in which they were submitted.
C - 0 6 - 1 ~ - 036Z
SOLUTIONS OF PRESSURE~SENSITIVE RESIN SOLUTIONS WITH
IMPROVED Vl~COSITY AND FLOW
BACKGROUND OF I~E IlWENTION
-
1. Fi~ld of the Invention
The present invention relates to organic solvent ~olutions
containing chelate esters of orthotitanic acid and resins with functional
groups capable of reaction with the esters. In another aspect, the
invention relates to a proces!Q of manuacture of articles containing
films of pressure-sensitive resilL
2, Description of the Prior Art
Pressure-sensitive resins are used conventionally in the
form of films to provide adhesive bonds between normally non-adhering
3uperstrates and substrates. The films may be prepared by casting them
from organic soIvent solutions and evaporating the ~olvent.
Constraints are placed on the molecular weight of the
pressure-sensiti~e resin by the viscosity of the solution necessary for
ease of coating on commercial coating machines and by the solution
concentration required for economical operation. In general, low solution
viscosity and high solution concentration are desired in the presslure-
sensitive resin solution, and, hence, a re~in of relatively low molecular
weight is preferred for film casting.
2(1 Onc e a bond has been made by a pressure-sensitive film
placed between a slubstrate and a 3uperstrate, the pres~ure-sensitive
film may be subjected to stress generated by the weight of the super-
strate or by dimenYional change in the substrate or superstFate caused
by thermal expansion, stress relaxation, plasticizer migration or the like.
In general, a high molecular weight and a high cohesive strength is
l~Zi~ 3
C-06-12-0362
desired in the pressure-sen3itive resin 50 that it may resist the
stresses induced in the adhesive film. The opposing requirements of
low molecular weight resin for ease of coating and high molecular weight
resin for load holding ability are conventionally reconciled by the use
of cros~linkable resin system~ which can be applied at low molecular
weight and cured to a high molecular weight.
Metal alkoxides ase taught by Blance in U. S. Patent
3, 53Z, 708 a~ crosslinking agent~ for solution pressure-sensitive
adhesives. They offer the potential of cure at room temperature merely
by evaporation of ~he solvent. Of particular interest have been tetra-
alkyl titanates which are formulated with hydroxy pressure-sensitiYe
re~ins in alcohol solutions to yield ~table solutions from which cross-
linked pressure-sensitive resins are obtained by evaporation of the
alcoholic solvent. However, such titanates particularly the lower alkyl
titanates impart high solution vi8c08ity and unde~irable flow to the re~in
solutions .
The undesirable flow is manifested by the tendency of
the resin solution to form a highly extended "string" or column of nuid
when a spatula or like object is pulled rapidly out of the solution.
ZO Solutions e~ibiting such "stringiness" are difficult to apply on modern
high-speed coating machinery. Uneven splitting and transfer of the
adhesive solution on the rolls causes uneven coating. On rever~e roll
coaters, the format.ion of strings at the roll nips produces a ribbed effect
in the coating and on gravure rolls, webs of solution produce coating defects.
There is, therefore, a need in the art for pressure-
sensitive resin solutions with suitable viscosity and flow for applicatie~n
by coating rolls ancl which yield pressure-sensitive resins curable at
--3--
~2~ 3
~;-06-1~!-0362
room temperature Dr at ~lightly elevated temperat~re~ to yield adequate
cohesiYe ~treng~h.
SUMMARY OF THE lNVENTlON
The above-mentioned need in the art is fulfilled by the
present invention which provide~ pressl~re-sensitive resin solutions with
improved viscosity and flow. The rressu]re-sensitive re~in ~olutions
comprise an orga~c solvent ~olution of:
~1) an interpolymer having a weight average molecular
we~ght in the range of 10, 000 to 50S), 000 and a glass tran~iffon tem-
perature in the range of -15 to -75C., the interpolymer comprisin~:
~A) behReen 0. 5 and ?0 weight per cent of at least
one monomer containing a hydroxyl, carboxyl or enolizable keto
group,
(B~ at least one monomer selected from the group
l~ consisting of esters of acrylic acid and methacrylic acid con-
taining from 6 to 20 carbon atom~, and
(iC) optionally, a monomer selected from the
group consisting of ~-olefin~ containing from 2 to l0 carbon
atoms, vinyl esters of alkanoic acid~ containing from 3 to 10
carbon atoms, ethyl and methyl esters of acrylic and methacrylic
acids, acrylonitrile, methacrylon~trile, styrene and vinyl chloride;
and
a chelate ester of orthotitanic acid having the
formula:
~2~ 3
C-06-12-036Z
¦ O---C / .
(RIO)n Ti~ C--R4
3 4-n
~herein n is an integer of 2 or 3, Rl is a C2 to C10 alkyl, alkenyl,
substituted alkyl or substituted alkenyl group, R2 is a Cl to C6
alkyl, alkoxy, alkenyl or alkenoxy group, E?3 is a Cl to C6 alkyl
or alkenyl group or a C6, to C10 aryl group and R4 is hydrogen or
a Cl to ~6 alkyl or alkenyl group, and R2 and R3 may be colnbined
as an ethylene or a trimethylene group.
The invention furtner provides a process for preparing ~`
pressure-sensitive resin solutions with improved viscosity and flow
arld a process or coating them as films on substrates to provide articles
of ~nanufacture coi~prising films of pressure-sensitlve interpolymer con-
taining tne above-described chelate esters of orthotitanic acid.
DESCRIPTION OF THE: INVENTION
The practice of the present invention involves the prepara-
-, tion of the interpolymer which is then formulated with the chelate ester
of orthot;t2nic acid in a ~uitable organic solvent. The solution is cast
on a substrate ~he or~anic solvent is dispelled and the resulting
lm is cured to a creep-resis~ant per~anently tacky compositlon.
The interpolymer comprises monomers selected from the
groups A, B, and C described above. Group A monomers contain
hydroxyl, carboxyl or enolizable keto groups. Monomers containing -
hydroxyl groups are exemplified by hydroxyalkyl acrylates,
methacrylates, fumarates or maleates
. ~ :
C;-06-1Z-0362
wherein the al~yl group contains from 2 ItO 4 carbon atoms. Pre-
ferred hydroxy monomers include 2-hydroxyethyl acrylate or meth-
acrylate, Z-hydroxypropyl acrylate or methacrylate7 3-hydroxy-
propyl acrylate or methacrylate, or bisl2-hydroxyethyl) fumarate
S ~r maleate. Monomers containing carboxyl grvups are exemplified
by acrylic acid, me~hacrylic acid, crotonic acid, iaocrotonic acid, and
the like, maleic acid, fumaric acid, citracon~s~ acid, itaconic acid,
and the like, and the alkyl monoesters of maleic acid, fumaric acid,
citraconic acid and itaconic acid in which the alkyl group contains from
1 to 8 carbon atomE~ ~3uch as me~hyl, ethyl, propyl, butyl and octyl
maleates and the like, Preferred acid monomers include acrylic acid
and methacrylic acid. Monomer:~ containing enolizable keto groups include
N, N-diacetonyiacrylamide and N, N-diacetonylmethacrylamide. The
amount of group A monomer in the interpolymer is generally in the
l range of 0. 5 to 20 weight per cent of the interpolymer, and is preferably
in the range of 1 to 10 per cent for adequate crosslinking potential with-
out excessive solution viscosity.
Group B monomers include ~he ester~ of acrylic and
methacrylic acid containing from 6 to 20 carbon atoms. Preferred e~ter~
contain branched chain alkyl groups such as isobutyl acrylate, 2-ethyl-
hexyl acrylate and 2-ethylhexyl methacrylate. The pressure-sensitive
resin need only contain monomers from groups A and B. However,
optionally, monomers from Group C may also be present. Group C
includes o~-olefins containing from 2 to 10 carbon atoms, vinyl esters
of alkanoic acids containing 3 to 10 carbon atoms such as vinyl acetate
and vinyl octoate, ethyl and methyl esters of acrylic and methacrylic
8~3
C-06-12-~362
acids, acrylomtrile, methacrylonitrile, styrene and vinyl chloride.
The ratio of monomers in the intf~rpolymer is selected
30 that the gla~s transition temperature is in the range of -15 to -75S;.
A suitable ratio i~ conventionally calculaLted from the equation:
1 Wl + W2 ~ _~_ Wn
Tg ~ Tg2 Tgn
where T is the glass transition temperature of the interpolymer
expressed as degrees Kelvin, Tgl, Tg2, etc. are the glass tranf~ition
temperatures of the homopolymers of the respective comonomers
and Wl, W2, etc. are the w~ight fractions of comonorners required
for a ~pecific glass tran~ition temperature of the interpolymer. GlasY
transition temperature~ are determined experimentally by conven-
tional method~ such as by means of the duPont Differential Thermal
Analyzer.
The weight average molecular weight of the interpolymer
is in the range of 10, 0Q0 to 500, 000, corre~ponding to a relative viscosity
in the range of 1. 3 to 8. 0 measured on a solution of 2 grams of inter-
polymer per deciliter of benzene. The preferred molecular weight
range is from 20, 000 to 300, 000, providing adequate cohe3ive strength
to the interpolymer without excessive solution viscosity.
The interpolymers are conveniently prepared by organic
solvent polymerization technique~ involving in ~ome cases delayed addition
of monomer when there is a great disparity between reactivity ratios as
for example between the reactivity ratio~ of vinyl acetate and acrylate
monomers. The time interval for the delayed addition may range from
ZS abollt 60 to about 600 minutes and longer. The techniquea in general,
'~ ~
:
;i8~93
C-06-1~-0~2
involve the polymerization of the respective monomer mixtures in
suitable orga~uc solvent~, the polymerization being initiated by heat
activated free radical initia~ors.
The choice of solvents for the interpolyrner used in the
prac~ce of this invention is governed by the solubility requirements of
the monomers and the resulting interpolymers in that both the monomers
and the resulting interpolymers should be soluble in the selected solvent
or mixture3 of solvents. A further requirement is that the interpolymer
solution should contain less than 3 per cent water by weight, ba~ed on
the total weight of the ss7lvent, In order to avoid adverse interference with
the metal alkoxide component. More preferably, t~e interpolymer 801u-
tion should contain less than 2 per cent water by weight.
Examples of ~uit~ble solvents for the interpolymers include
aromatic solvents such as benzene, toluene, xylene, etc. Suitable
aliphatic solvents include esters such as ethyl acetate, propyl acetate,
i~opropyl acetate, butyl acetate, etc.; ketones such as methyl ethyl ketone,
acetone, etc" aliphatic hydrocarbons such as hexane, pentane, etc.
Especially useful are mixtures of the foregoing.
The polymer systems of this invention may also be prepared
in mass or non-aqueou~ dispersion type polymerization processes as
are well known to those skilled in the art. However, solution poly-
merization processes are preferred~
Polymerization initiators suitable for the preparation
of the special interpolymers of this invention include organic peroxides,
such as tert-butyl hydroperoxide, di-tert-butylperoxide, cumene hydro-
peroxide, di-cumyl peroxideJ be~szoyl peroxide and the like. Equally
C - Q 6 - 1 2 - 03 62
suitable are organic peroxygen compounds 0uch a~ tert-butyl per~ceta~e,
acetate, tert-butyl perbenzoate, di-tert-butyl perphthalate; other
initiators would include o~ azo-di-isobutyronitrile, ultraviolet
light, gamma radiation, etc.
The following Examples 1 to 13 illustrate the preparation
formulation and testing of the special interpolymers which are to be
used in the practice of this inYention and are not to be construed as
limitations thereof. All part~ and percentages are by weight unless
otherwi3e specified and the expres~ion~ polymer and interpolymer are
1 0 us e d inter changeably.
PREPARATION OF INTERPOLYMERS
Example 1
Thi~ Example illu~trates the preparation of an inter-
polymer comprising 50. 5 part~ 2-ethylhexyl acrylate, 45 part3 methyl
acrylate and 4. 5 part~ 2-hydroxyethyl acrylate.
The polymer is prepared under reflux cunditions in a
kettle equipped with a stirrer, condenser, holding tanks and pumps.
AMOUNT OF INGREDIE:NTS, Parts by Weight
Initial Subsequent charge3
Charge 1 2 3
2-ethylhe~yl acrylate 14. 1 6. 97
Methyl acrylate 12. 6 6. 20
2-hydroxyethyl acrylate 1. 26 0. 62
Ethyl acetat,e 19. 6912. 3 9, 0
~Iexane S. 14 2.749.26
oC, O~ ' -azo-diisobutyronitrile 0. 07 6 0. 038
Dodecyl mercaptan 0. 0027 0. 0013
393
C-06-lZ -0362
Charges 1 and 2 are made at uniform ratc~ ov~r thc
14 hour period after the initial charge reaches reflux~ After 6i! hours
of reflux, the batch is cooled and charge 3 is added. The solids content
is 41. 0 per cent. The Brook~ield viscosity is 3, 000 cps. The relative
5 viscosity, determined with a solution of 2 grams of resin in 100 ml. ben~ene
is 4.1.
- Examples 2 to 11
The gene~al procedure of Example 1 is followed except
that different monomers and monomer ratios are used in order to
illu3trate a variety of interpolymer~ used in the practice of this invention.
- TABLE 1
COMPOSITIONS OF INTERPOLYMERS
- ~EPARED IN EXAMPLES 1 to 11
.. . _ _ . .. .
Ex:. Monomeric Components Weight Ratio
- 15 1 EHA/MA/HEA 50. 5145/4. 5 $
i~ EHA/YAc/AA 59/39. 5/1. 5
3 EHA/VAc/AA - 52/47/1. 0
4 EHA/~A/AA Sl/33/6. 2
EHA/I~A/HEA 71/Z4/5
6 iBA/MA/HEA 71/24/5
7 VAc/EHA/HPA 45/50/5
8 VActEHA/HEMA 35/60/5
9 VAc/EHA/HEF 40/55/5
AN/EHA/HEMA 25/70/5
11 VCl/EHA/HEMA 30/65/5
-10-
~J.~ 3
C-0~-12-03~
L EGE ND
EHA 2-ethylhexyl acrylate
~L~ m ethyl acrylate
HEA 2-hydroxye~hyl acrylate
YAc vinyl acetate
~ acrylic acid
H PA 3-hydroxypropyl acrylate
HE~ 2-hydroxyethyl m ethac~ylate
H EF bis-(2-hydroxyethyl3furnarate
A N acrylonitrile
VCl vinyl chloride
iBA isobutyl acrylate
. ,
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o g o g g o o o o o
~ t, o o o o ,~, o CO U7 ~
~1 ~> ~ n ~f~ t~
O ~ .
o u~ l ~r tl) tn ~ ~, ~ ~ ~ ~
~il O , , , , o
N N N I I
l, h ¦ ~ I , o , , , ,
; ~ ~ ~lo o n O co I ~ '
o ~ r
Z
,, ~ O I ~ I ~ I CO
: O ~
~,
,..................... ¢ o o o u~ O ~ ~r ~ o o
, ~
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--12--
C-06-12-0362
FORMULATION OF RE~SIN SOLUTIONS WITH
CHELATE_TE~RS OF ORTHOTITANIC ACID
After the preparation of the interpolymer, the interpoLymer
solution is formulated with at least one chelate ester of orthotitanic acid
of the general formula:
(Rl~n Ti O=C\
R3 4-n
`:
- wherein n is an integer of 2 or 3, Rl is a C2 to C10 alkyl, alkenyl, sul~-
stituted alkyl or substituted alkenyl group, Rz is a Cl to C6 alkyl,
alko~y, alkenyl or alkeno~y group, R3 is a Cl to C6 alkyl or alkenyl
group or a C6 to C1 0 aryl group and R4 i9 hydrogen or a Cl to C6
alkyl or a~kenyl group, and R2 and R3 may be combined as an ethylene
or a trirnethylene group.
The chelate esters are prepared by conventional Inethods
such as the addition of the appropriate chelating agent to an alkyl or alkenyl
titanate wherein the alkyl or alkenyl group contains 2 to 10 carbon atom3.
Among the chelating agents which can be used are, for example,
acetylacetone, propionylacetone, benzoylacetone, 1, 3-cyclopentandione,
1, 3-cycloheY~ndione, alkyl acetoacetates, such as ethyl acetoacetate,
and the alkyl and alkenyl substituted derivatives of these diketone~ and
acetoacetates. Thus, where acetylacetone is used as the chelating agent
the Rz and R3 groups are methyl and the R4 group iY hydrogen. The
chelating agents may be reacted with the lower alkyl or alkenyl titanate
in a molar ratio ranging from 1:1 to 2:1. The preferred ratio is about
_13-
~" .
~R.~Zfi~33
~:1 so that, for example, when acetylacetone is used, a di-
alkoxy titanium diacetylacetonate is obtained. The alkanol
generated by the reaction may be distilled~ Alternatively,
it may be allowed to remain so -that the product of reaction is
essentially a solu-tion of chelate ester in alkanol. The pre-
ferred chelate esters are dialkoxy titanium diacetylacetonates,
dialkoxy titanium di(l,3-cyclopentandiona-tes) and dialkoxy
titanium di(l,3-cyclohexandionates).
The ~mount of chelate ester used in a given resin
solution will depend on the type of reactive group in the
interpolymer, the molecular weight of the interpolymer, the
concentration of interpolymer in the solution, the composition
of the solvent and the degree of cross-linking desired in the
pressure-sensitive resin after it has been cast from solution.
As little as 0.01 parts by weight of the chelate ester per 100
parts by weight of interpolymer can give a significant effect
on the cohesive strength of the polymer as measured ~y -the
creep resistance. As much as 4.0 parts by weight of the
chelate ester per 100 parts by weight of interpolymer can be
used especially with lower molecular weight interpolymers and/or
: lower concentrations of functional groups. However, the pre-
erred range is between 0.1 and 1.0 parts by weight per 100
parts of interpolymer to achieve an appreciable degree of
crosslinking without an undesirable increase in the viscosity
of the resin solution.
Unlike the lower alkyl titanates, the chelate esters of
orthotitanic acid may be added to the interpolymer solutions
in the absence of highly polar solvents such as the lower
alcohols and much higher concentrations of resin and chelate
ester can be achieved in the solution without excessive
viscosity, stringiness or gelling. However, it may
~ -14-
~3~ i8~93
~-06-12-0362
still be advantageous to include a lower alcohol in the ~esin solution
to increase the solubility parameter of the solvent, particularly ~,vhen
the sub~trate to be coated can be swollen by the less polar solvents which
are conventionally uaed in the aolution interpolymerization proces~.
Apart from the optional use of a lower aloohol, conventional solvents
and solvent blends are selected for use in the pressure-sensitive resin
solutions of thi3 invention on the basis of the solubility requirements of
the resin and the nature of the substrate which is to be coated, The solids
content of the resin solutions can be varied between 10 per cent and 60
per cent for application to the substrate. The preferred concentration
iB between 20 and 50 per cent.
EVALUATION OF PRESSURE-SENSITIVE
RESIN SOLUTIONS
In the evaluation of pressure-sensitive resin ~olutions
containing esters of orthotitanic acid, the solutions are formulated to
32 weight per cent solids. The esters of orthotitanic acid are added
in ethanol solution gradually with stirring to the pre~sure-sensitive
resin solution, the amount of ethanol being 25 weight per cent of the total
solvent in the final solution.
The solution~ are subjected to determination of viscosity
and "stringiness index". Viscosity iB determined at 20C, by the
conventional method using a Brookfield Model LVF Viscometer and the
appropriate spindle and speed. Vi9cosity stability is determined from
viscosity measurennents over a 7 day period.
The stringiness index (S. I. ) i~ determined by immersing
a platinum surface tension ring of 3. 6 cm diameter, -one inch below the
-15-
~3~ 3
C -Ob- lZ -036 2
surface of the pres~ure-sen~itive reain ~olution contairled in a 7.62 cm
diameter jar. The ring i~ mounted in the jaw of an ln~tron l'est Machiné
and is withdrawn from the solution by allawing the cros~he~d upon which
the jar rests to de~cend at a rate of 12.7 cm/mln. The tensile
S fs~rce exerted on the ring i~ recorded by means of the A cell on the chart
oct at lO ~ram~ full RCalC and moVi~ t 12.7 crn/min. I h~
stringi~e~s index is mea~ured from the peak of rr1aximum extensional
force to the failure point of the elongating curtain of ss>lution. Five
mea~uremel~t~ are made in rapid succession. The arithmetic average
0 e~cpre~o~d in cms. i8 the ~tringine~s index. In general, a stringiness
index of le~ than o.76 cm indicatee that a resin solution haa good 10w
properties and that the solution will not form string~ on conventional
high-~peed roll coaters at normal speeds of operation. The tendency
of a pressure-sensitive reAin solution to develop ~tringiness is determined
by measurement of the stringines~ index over a 7 day period.
The dlata for viscosi2y and stringine~ index of Ihe inter-
polymer ~olutions of Examples 1-4 formulated with various esters alf
orthotitanic acid are preiented in Tables 3 and 4. The ~olids content of
the solutions i3 32 per cent. Ethanol forms 25 per cent of the solvent.
'O In the Tables, TBT ~ignifies tetrabutyl titanate and TAA signifies di-
isopropoxy titanium diacetylacetonate which i~ formed by rea~ 2ion of
2 rnole~ of acetylacetone with 1 mole of tetra-isopropyl titanate.
-16-
~fi893
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:~ ~o3~ o~ o ~
. ~ ¢-. , _.
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¢ ~
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.~ o~ o ~ u~
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f~ _ ¢ 3 a ~ ~ ~0
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¢Z ~
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0
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--17--
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~Z~ 93
C-06-lZ-036Z '
o o o o ,~ o
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op, ~'
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a~
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o
, O ~ o o oo o ~ P~ ~3
P' 3 1.
O ~ OO OO O 1- D ~ W
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oo oo 1 ~ ~ -
o l- o ~ o o o ~ , ~ ~ C~
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x
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CO ~ ~n ~ ~ W ~ ~ P
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t
-18-
'
The data show the higher viscosities, the tendency to
gel and the hi~her stringiness indices of pressure-sensitive
resin solutions containing -tetrabutyl titanate in comparison
with solutions containing diisopropoxy titanium diacetyl-
acetonate especially at higher concentrations of the titanateester.
Data for stringiness index of interpolymer solutions
of Examples 3 and 6 through 11 formulated with various chelate
esters of orthotitanic acid are presented in Table 5. The
solids content of the solutions is 30 percent. Ethanol forms
25 percent of the solvent. The concentration of chelate ester
of titanium is 0.4 parts per 100 parts by weight of resin.
~- EVALUATION OF PRESSURE-SENSITIVE RESINS
The pressure-sensitive resin solutions listed in
Table 3 are cast on silicone release paper, and the cast films
are dried at room temperature, then at 90C. for 2 minutes to
dispel the organic solvent. The (0.002 cm thickness) films are
cooled to room temperature and applied to polyvinyl chloride
film (Ultron* Polyvinyl Chloride UL-58 Film, 0.0076 cm thick,
supplied by Monsanto Company). The laminate is cut into 2.54
cm strips. The strips are conditioned at 22C and 50~
relative humidity for 24 hours. The release paper is removed
and the strips are applied to steel panels (ASTM 1000-651 with
a Pressure-Sensitive Tape Council roller. Peel strength is
determined on an Instron Test Machine by peeling the strip
at a 180 angle and at a rate of 15.1 cm per minute from the
steel panel. "Green" strength is gauged by comparing the
peel strength of the bond 20 minutes after formation and 24
hours after formation. Data are presented in Table 6.
* Trademark
--19 -
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U~ X o o~ 1 ~ 1~ ~ 3 C~
~1 ~1 ~ 0 ~ 3 3
`O ~' ,1: 3 0 t~
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93
C-06-12 -0362
The data show that titanate ~ter causes a decrease
;n peel strength in direct relation to f,he concentration of titanate
ester, Ho~ever, the effects of tetrabutyl titanate and diisopropoxy titanium
diacetylaceton~te are essentially equivalent and in no case is the peel
st}ength reduced below a useful value,
The co~lesive strength nf the pressure-sensitive
adhesive is gauged from the creep resistance of a 1.61 cm;~ 0.002cm
thick bond formed by the film of adhesive between a strip of Mylar*
Polyester filrn ~a product of E. I, duPont de Nemours and Company) and
a polished stainless steel bar, The Mylar*strip is loaded with a one-
pound weight, The bond is held in a vertical plane at 22C and 50%
relative humidity and the tirne in hours for failure after application
of the load is determined, The data are presented in Table 7,
TABLE 7
CRE~EP RF:SISTANCE OF PRESSURE-
SENSITIVE RESINS ~hours to failure)
Titanate RESIN
Concentration, g. ~ ~x. ~;x, ~;x.
per 100 g, re~in Type 1 2 3 4
0 none 0, 2 0, 3 0, 7 0, 5
0, 2 TBT 3 3 4, 6 -_
TAA 3 2 4 10
0. 4 TBT 10 55 40 --
TAA 25 15 55 25
0, 6 TBT -- 52 -_ __
TAA 5S 145 155 --
* Trademark
~ %~ ?t3
C-06-12 0362
Note that at loYv coneentrations of titanate e~ter, the
initial creep resistance i~ roughly the same for resins containing
tetrabutyl titanate and those containing diisopropoxy titanium
diacetylacetonate;but at higher concentrations, the creep resistance
improves to a higher level for TAA formuiations than iEor the TBT
systems. An exception is the Exampl~ 2 system for which TBT may
be a more efficient crosslinker.
While the present invention has been described with parti-
cular reference to certain spec;fic embodiments thereof, it will be
understood that certain changes, substitutions and modifications may be
made therein without departing from the scope thereof. This invention
also contemplates the use of filler3, extenders, s~abili~;ers, antioxi-
dants, plasticizers, tackifiers, flow control agents, adhesion promoters,
dyes, etc. in the pressure-sensitive resin solutions and the pressure-
sensitive resins of this invention.
The compositions of the present invention may be used
as the adhesive component in pressure-sensitive tapes, films and foams.
They adhere well to resin 3urfaces such as plasticized polylvinyl chloride3
Mylar, cellulose acetate, nylon, polyethylene and polypropylene, as well
as to paper, metal and painted surfaces. They are e3pecially useful as
the adhesive component of decorative vinyl sheets and decals, conferring
- excellent shrink resistance to vinyl film. Their excellent tack retention,
creep resistance and resistance to plasticizer migration make them u3eful as
adhesives for vinyl foam and tile~.Their outstanding tack, wetting and holding
power may be used to advantage in transfer adhesive applications.
8~3
C - 0~ - 1 2 - 03 62
Articles of manufacture ~uch as tapes, decals, decorative
vinyl 8heet8 and transfer films containing the pressure-sensitive re~in
composition of the present invention are prepared by coating the resin
on the appropriate substrate by conventional coating methods. Such
artieles conventionally include a release paper for teml?orary protection
of the adhesive film until lhe adhesive l~-n-l is rna~le. The thi~:kn~s~
of the adhesive film is generally in the range of 0.00051 to 0.0127 cm
Application of the film to the sub~trate is conventionally
carried out on roll coater~ ~uch as reverse roll and gravure roll coater~.
The resin ~olution visco~ity i~ adjusted to between 25 and 5, 000
centipoiRe~ with higher viscositieu within the range preferred for reverse
roll coating and lower visco3ities within the range preferred for gravure
coating. The coatings are applied to the substrate moving through the rolls
a~ a rate of between 5.1 cm~sec. and ~o~.n n~m/~?C.
Example l 2
This ~:xample i8 ~let forlh lo colllpdre Ille perforll~al~ce
of a resin aolution formulated with letrabutyl titanale with a resin
solution formulated with diisopropoxy titanium diacetylacetonate in reverse
roll application to a polylvinyl chloride) substrate at a rate of 25.4 cDnJ~ec.
Polymer solutions made according to Example l are diluted
to 30 per cent solids and formulated with 0. 5 parts tetrabutyl titanate
or diisopropoxy titanium diacetylacetonate per lOO parts of resin. The
levels of titanate con~pound are ~elected to give the desired cohesive
~trength in the dried films. The TBT solution had a Stringiness Index of
about 1.14 cms. and g:ives poor coatings of rough surface texture and uneven
Ihi~:hn~ . A l~r~ ul~ r ~f "~IrinK~" ~re ~ erve(l I)etw( (~n Ine
_ 2 4 _
..
. . . . . . . .
C-06-12 -0362
application roll and Lhe sub~tra~te during tile coating operation. Th~ ac
coatinga are judged unsuitable Ior commercial u~e. The TAA solution
has a Stringpness Lndex of abous Q.50 cm. and gives smooth coatings of
uniforln thickneas. These filma are judged satisfactory for commercial
u~e.
.~ .
~ -25 -
