CA1145095A - Adhesive composition and method of preparation - Google Patents
Adhesive composition and method of preparationInfo
- Publication number
- CA1145095A CA1145095A CA000354121A CA354121A CA1145095A CA 1145095 A CA1145095 A CA 1145095A CA 000354121 A CA000354121 A CA 000354121A CA 354121 A CA354121 A CA 354121A CA 1145095 A CA1145095 A CA 1145095A
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- Prior art keywords
- solvent
- weight
- resin
- range
- block polymer
- Prior art date
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J153/00—Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
- C09J153/02—Vinyl aromatic monomers and conjugated dienes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
- C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
- C08L2666/28—Non-macromolecular organic substances
Abstract
Abstract Adhesive composition comprised of an unvulcanized block polymer product and a compatible tackifier resin.
Said adhesive composition is required to be prepared by (A) mixing a solution of a block styrene/isoprene polymer product with a solution of a tackifying resin and (B) optionally removing the solvent.
Said adhesive composition is required to be prepared by (A) mixing a solution of a block styrene/isoprene polymer product with a solution of a tackifying resin and (B) optionally removing the solvent.
Description
~5~5 Field of Invention This invention relates to adhesive compositions and method of preparation. The invention has particular reference to pressure sensitive adhesives of both the solution cast and the hot melt application -types.
Back~round of Inven-tion Various adhesives can individually be advantageously used as pressure sensitive, laminate or hot melt adhesives.
Most are generally known for their ability to form articles by bonding laminates together. Some are more particularly known as pressure sensitive adhesives and some as hot melt adhesives.
Pressure sensitive adhesives and adhesive-coated masking tapes and the like are well known. These products commonly contain a mixture of natural rubber or styrene/
isoprene/styrene block polymer and a thermoplastic tacki-fier resin compatible therewith. The adhesive, coated on a flexible backing to form a tape, is tacky at normal room temperatures and adheres instantly and tightly to surfaces against which it is pressed without requiring moistening or heating. It typically is required to have a balance of good shear strength, a satisfactory 180 peel strength, and good tack property in order to be commercially useful.
Adhesives are many times based on mixtures of rubbery materials and tackifiers. Pressure-sensitive adhesives typically require more sophisticated properties than simple tackified rubber compositions. They must have espe-cially balanced properties of adhesion, cohesion andelasticity in addition to peel and shear strengths to be useful for adhering materials together on a pressure sensitive basis.
Many times, pressure-sensitive adhesives can be based on mixtures of tackifiers with natural rubber or with ~1 ~5~9S
block copolymers of isoprene and styrene. HQwever, such adhesive composites are often deficient in desirable properties.
It is, therefore, an object of this invention to provide an adhesive composition of a tackifier and a rubbery block polymer product of styrene and isoprene.
Disclosure and Practice of Invention In accordance with the present invention, there is provided an adhesive composition which comprises an admixture of an unvulcanized block polymer product and a compatible tackifier resin therefor prepared by the method which comprises mixing (l) lO0 parts by weight of a solution comprised of 100 parts by weight of an unvulcanized block styrene/iosprene polymer product with an overall styrene polymer content in the range of about lO to 35 weight percent and a solvent therefor in the range of about 300 to about llO0 by weight with (2) about 50 to about 200 parts by weight of a solution comprised of lO0 parts by weight of a tackifying resin for said block polymer product and a solvent therefor in the range of about 25 to about 1100 parts by weight, wherein the total of said solvent(s) is a solvent for the combination of said block polymer and said resin; wherein said block polymer is (i) produced by the process of cotacting isoprene and a suitable amount of divinylbenzene under solution polymerization conditions with a polystyryllithium catalyst, said amount of divinylbenzene being from about 0.5/l to about lO/l moles of divinylbenzene per mole of active lithium catalyst or is (ii) of the linear or radial type styrne/isoprene/styrene block copolymer prepared by sequentially polymerizing styrene and isoprene with a lithium based initiator and wherein said tackifier resin is selected from terpene resins and synthetic hydrocarbon-de~yed ~es~ins of diolef~nlolefin copolymers having a softening point in the range of aoout 70~C., to about 11.5C.
f~
. ~ - 2 -In addition, the present invention prov~des a ,m,ethod ~f p~eparing an adhesive composition which comprises ~) m~xing (1) 1OO parts by weight of a solutlon comprised o~ 100 parts by weight of an unvulcanized block styrene/
isoprene polymer product with molecular weight in the range of 8,000 to 45,000 and overall styrene polymer weight in the range of about 10 to 35 weight percent and a solvent therefor in the range of about 300 to about 1100, prefera'bly about 400 to aboutlOOO,.partsbyweight with (2) about 50 to about 200 parts, preferably about 100 to about 150, by weight of a solution comprised of 100 parts by weight of a tackifying resin for said block polymer product and a solvent therefor in the range of about 25 to about 1100, preferably about 100 to about 1000, parts by weight and (B) optionally removing said solvent from the prepared mixture prior to its application as an adhesive; wherein the total of said solvent(s) is a solvent for the combination of said block polymer and said resin; wherein said block polymer is produced by the process of contacting isoprene and a suitable amount of divinylbenzene under solution polymerization conditions with a polystyryllithium catalyst, said amount of divinylbenzene being from about 0.5/1 to about 10/1, preferably about 0.5/1 to about 3/1, moles of divinylbenzene per mole of active lithium catalyst and wherein said resin has a softening point in the range of about 70C. to about 115 C.
- 2a -gs The (B) option of removing the solvent before appli-cation would be used for hot melt adhesive applications.
For solution adhesive applications, solvent could be retained or the mixture dried and redissolved prior to application.
It is an important feature of this invention that the adhesive composition can be prepared by directly mixing the polymerizates of either or both the block polymer product composed of (A-l) and/or the resin poly-merizate composed of (A-2).
Thus, the adhesive composition can be formed by a method selected from (A) mixing the block polymer poly-merizate ~ith a solution of the solid resin dissolved in its solvent, (B) mixing a solution of the solid block polymer product dissolved in its solvent with a solution of the solid resin dissolved in its solvent, (C) mixing a solution of the solid block polymer dissolved in its solvent with the resin polymerizate or (D) mixing the block polymer polymerizate with the resin polymerizate.
The term polymerizate is intended to refer to a solution of the block polymer produc-t or resin as a direct result of its preparation or polymerization, of its precursor monomers in the presence of its solvent and catalyst, deactivated and optionally removed.
The terms solid block polymer product and solid resin refer to such materials in their recovered form from the polymerizates. When they are dissolved in their solvent they become a solution. It is readily recognized that this solution~forming procedure from the solid prod~ct requires an additional step and effort as compared to the utility and/or convenience of directly using the polymerizate.
In the practice of this invention, the blending or mixing process can be generally accomplished, for example, by using a turbine blade agitation system for a period of about three hours at about 20C. to 30C.
~5~95 The adhesive composition can conveniently be recovered, for example, by application of conventional steam stripping and drying procedures, such as oven drying, to remove solvent.
It was unexpectedly found tha-t by using the solution preparation process of this invention, a resulting adhe-sive composition was observed having increased tack, faster molten solution time and excellent tack retention of the hot melt blend properties as compared to simply dry blending the block polymer product and tackifying resin.
A disclosure of such dry blending can be found in United States Patent No. 4 ,172,860.
In order to effectively provide a solution of the resultant adhesive composition by the method of this invention, it is readily understood that solvents or solvent mixtures are selected in which -the block polymer product and the resin are mutually soluble. For example, the block polymer product is generally soluble in aromatic hydrocarbons such as toluene and benzene as well as some cycloaliphatic hydrocarbons such as cyclohexane, cyclo-pentane and methylcyclopentane. Tackifying resins are also usually soluble in such solvents with some being soluble in aliphatic hydrocarbons and chlorinated aliphatic hydrocarbons. Mixtures of solvents can be used with solubility advantages tailored to both the block polymer and resin. It is generally preferred that the solvent or solvent mixture of the resulting mixed solutions contain about 80 to about 100 weight aliphatic hydrocarbon solvent based on the solvent(s) alone. Thus, the choice of solvent or solvent mixture must depend upon the type of resin used as well as the block polymer product which can readily be determined by one having skill in the art. The term hydrocarbon solvent is intended to refer to liquid hydrocarbons and liquid halo-substituted hydrocarbons.
1~, In the prac-tice of this invention, said tackifier is a resin preferably having a softening point in the range of about 50C to about 150C, preferably about 70C to about 115C, and is preferably selected from at least one of terpene resins and synthetic hydrocarbon derived resins of diolefin/olefin copolymers. Coumerone-indene type resins may be satisfactory. The diolefin/
olefin copolymers are generally of the type prepared by copolymerizing in the presence of a catalyst selected from aluminum chloride or boron trifluoride or boron trifluoride etherate, a mixture of piperylene and at least one olefin containing 4 to 6, preferably 5 to 6, carbon atoms in a diolefin/olefin mole ratio in the range of about 0.6/1 to about 2.5/1, preferably about 0.8/1 to about 1.6/1. Optionally, said copolymer can be modi-fied by copolymerizing therewith about 5 to about 20 weight percent, based on the total monomers, of at least one additional monomer selected from a-methylstyrene and dicyclopentadiene. Some of such resins can have melting points according to ASTM E28-58T less than the required range. However, lower softening resins can be conveniently mixed with higher softening point resins to achieve the required range.
A particularly desirable type of tackifying resin is prepared from piperylene and 2-methyl-2-butene in about 0.8/1 to abou-t a 1.6/1 mole ratio, with the optional inclusion of a-methylstyrene and/or dicyclopentadiene.
Aluminum chloride would be a preferred catalyst In the further practice of this invention, the unvulcanized elastomeric block copolymer (i) preferably has its first polystyrene block with a molecular weight in the range of about 8,000 to about 45,000 with the overall styrene content in the copolymer being in the range of about 10 to about 35 weight percent, preferably 10 to 20 percent.
Additional description o~ a required block copoly-mer (i) for -this invention and methods for its prepara-tion are found in U.S. Patent 3,949,020.
~915~:19~;
In -the block copolymer (i), -the molecular weight of the polystyrene block and the molecular weight of the polydiolefin block can range quite broadly. Also, the weight ratio between the polystyrene and the poly-diolefin can range quite broadly. The polystyreneblock molecular weigh-t can range from about 8,000 to about 45,000. The polydiolefin block molecular weight, ignoring the effect of the divinylbenzene (DVB), can range from about 10,000 to about 100,000. It should be understood that one skilled in the art could adjust these molecular weight limitations and ratios to produce a host of materials ranging from soft, rela-tively weak (tensile at break 500 psi) adhesive sub-strates, through tough thermoplastic elastomers, to plastics. Because these materials are branched, they are more easily processed than their linear counter-parts.
The polystyryllithium catalysts useful in the pre-paration of the block copolymer are those that corres-pond to the formula RLi, in which R is polystyreneprepared by reacting alkyllithium with a styrene monomer solution forming polystyrene with a lithium atom at one end of the styrene chain. The alkyllithiums which can be utilized in the instant invention are n-butyllithium, secondary butyllithium, isopropyllithium, amyllithium, etc. Similarly, substituted styrenes such as p-methyl-styrene, p-t-butylstyrene, or o-ther substituted styrenes may be used in place of styrene, although ~or this invention, generally only styrene is preferred. For instance, if a styrene-isoprene block polymer branched along the polymer chain of the polyisoprene block to other styrene-isoprene units is to be prepared, the n-butyllithium is reacted with a styrene solution to make a polystyryl lithium catalyst which can then be added to an isoprene solution containing the branching agent and polymerizing the isoprene solution until the desired block polymer is formed.
s The polymerization reaction is usually carried out in an inert solvent such as a hydrocarbon. It has been found however that all hydrocarbons will not be particularly conducive. Some hydrocarbons that can be utilized for preparing the copolymer are benzene, toluene, cyclohexane, cyclopentane and me-thyl cyclopentane.
The unvulcanized elastomeric block copolymer (ii) of the linear or radial type which can be used in this inven-tion comprises nonelastomeric terminal styrene polymer blocks having a molecular weight in the range of about 5000 to about 30,000 and internal elastomeric isoprene polymer blocks having a molecular weight in the range of about 50,000 to about 150,000, where the styrene polymer block(s) is about 10 to about 30 weight percent of the copolymer. The characteristics of the internal or middle block, which is elastomeric, might be expressed in ASTM
Special Technical Bulletin No. 18L~ as follows: "A sub-stance that can be stretched at room temperature to at least twice its original length and, after having been stretched and the stress removed, returns with force to approximately its original length in a short time."
The terminal nonelastomeric blocks constitute poly-meric blocks which do not meet this definition. Further-more, the difference between glass transition temperatures f the end blocks and middle blocks should be at least 40C and preferably at least 100C.
Typically, the unvulcanized elastomeric copolymers (i) can be prepared by first polymerizing styrene with a lithium based initiator. A suitable lithium based ini-tiator is, for example, lithium metal, alkyl li-thium com-pounds, lithium hydrocarbyls and organo lithium amides.
The alkyl lithium compounds are preferred. Particularly preferred alkyl lithium compounds are branched chain, preferably secondary alkyl lithiums. Such alkyl lithium compounds especially include secondary butyl lithium, isobutyl lithium, isoamyl lithium and secondary amyl lithium.
~s~s After polymerizing the styrene -to an average molecu-lar weight of from about 2000 to about 100,000, and preferably from about 5000 to about 30,000,isoprene and additional amounts of styrene are added to the poly-meriza-tion mixture.
The polymerization then continues to provide an elas-tomeric middle block isoprene polymer having an average molecular weight of from about 25,000 to about 1,000,000, and more preferably between about 50,000 and about 500,000, followed by a non-elastomeric styrene block polymer to provide the block copolymer effect.
Typically, the preparation of the elastomeric block copolymer is made by polymerizing the monomers at tempera-tures in the order of about -20C. to about 100C., prefer-ably between about 20C. and about 65C. in an inert hydro-carbon solvent such as an alpha olefin or aromatic hydro-carbon. Typically inert hydrocarbon solvents are ali-phatic hydrocarbons (including cycloaliphatic) such as cyclohexane and a typical aromatic hydrocarbon is benzene.
Usually the amount of initiator should be maintained as low as possible, but may be varied over a relatively wide range such as from abou-t 1 to about 200 par-ts per million, based on the weight of the monomers present.
In the practice of this invention, the adhesive com-position is useful for bonding substrates together.Although utility as a solution cast adhesive can be shown, the adhesive composition prepared by this invention has been found to particularly provide an enhanced usefulness in hot melt adhesive applications. Apparently the solu-tion mixing as a method of preparation is an important factor.
The adhesive composition of this invention can ~ suitably bond substrates together such as by simply ; applying it as a hot melt to substrate surfaces and adhering the surfaces together with a thin film of the mixture therebetween. Alternately, it can be applied sl~9s in its solution form. The mixture solution is applied to at least one of the substrate surfaces, followed by at least partially drying it to enhance its tack, bringing -the substrate surfaces together with the application of pressure and drying the adhesive to enhance the bond.
Pressure-sensitive tapes can be prepared by applying a solution of the adhesive composition to a flexible substrate and drying it.
The composition, as a hot melt pressure sensitive adhesive, can be prepared by mixing the block copolymer, tackifying resin, and thermoplastic polymer such as poly-ethylene, polyisobutylene, polystyrene, poly-a-methyl-styrene, ethylene-vinyl acetate copolymers and a minor amount of an oil such as petroleum-derived or coal tar-derived oil such as mineral oil or rubber processing cil.The hot melt adhesive is applied by heating the mixture, applying it to a substrate and cooling.
In the preparation of the adhesives of this invention it is understood that minor amounts of various antioxidant and fillers can be mixed therewith.
The following examples further illustrate the inven-tion and are not intended to be limiting. The parts and percentages are by weight unless otherwise indicated.
Example I
A resin is prepared as follows:
To a reactor is charged 200 parts of heptane and 6 parts of anhydrous aluminum chloride at a temperature of about 25C. While stirring the mixture, 400 parts of a hydrocarbon mixture containing unsaturated hydrocarbons is slowly added to the reactor over a period of about 90 minutes. The temperature of the reaction is maintained at about 25C to 30C for about 60 minutes. The hydro-carbon mixture has the following composition:
5~S
Component Parts
Back~round of Inven-tion Various adhesives can individually be advantageously used as pressure sensitive, laminate or hot melt adhesives.
Most are generally known for their ability to form articles by bonding laminates together. Some are more particularly known as pressure sensitive adhesives and some as hot melt adhesives.
Pressure sensitive adhesives and adhesive-coated masking tapes and the like are well known. These products commonly contain a mixture of natural rubber or styrene/
isoprene/styrene block polymer and a thermoplastic tacki-fier resin compatible therewith. The adhesive, coated on a flexible backing to form a tape, is tacky at normal room temperatures and adheres instantly and tightly to surfaces against which it is pressed without requiring moistening or heating. It typically is required to have a balance of good shear strength, a satisfactory 180 peel strength, and good tack property in order to be commercially useful.
Adhesives are many times based on mixtures of rubbery materials and tackifiers. Pressure-sensitive adhesives typically require more sophisticated properties than simple tackified rubber compositions. They must have espe-cially balanced properties of adhesion, cohesion andelasticity in addition to peel and shear strengths to be useful for adhering materials together on a pressure sensitive basis.
Many times, pressure-sensitive adhesives can be based on mixtures of tackifiers with natural rubber or with ~1 ~5~9S
block copolymers of isoprene and styrene. HQwever, such adhesive composites are often deficient in desirable properties.
It is, therefore, an object of this invention to provide an adhesive composition of a tackifier and a rubbery block polymer product of styrene and isoprene.
Disclosure and Practice of Invention In accordance with the present invention, there is provided an adhesive composition which comprises an admixture of an unvulcanized block polymer product and a compatible tackifier resin therefor prepared by the method which comprises mixing (l) lO0 parts by weight of a solution comprised of 100 parts by weight of an unvulcanized block styrene/iosprene polymer product with an overall styrene polymer content in the range of about lO to 35 weight percent and a solvent therefor in the range of about 300 to about llO0 by weight with (2) about 50 to about 200 parts by weight of a solution comprised of lO0 parts by weight of a tackifying resin for said block polymer product and a solvent therefor in the range of about 25 to about 1100 parts by weight, wherein the total of said solvent(s) is a solvent for the combination of said block polymer and said resin; wherein said block polymer is (i) produced by the process of cotacting isoprene and a suitable amount of divinylbenzene under solution polymerization conditions with a polystyryllithium catalyst, said amount of divinylbenzene being from about 0.5/l to about lO/l moles of divinylbenzene per mole of active lithium catalyst or is (ii) of the linear or radial type styrne/isoprene/styrene block copolymer prepared by sequentially polymerizing styrene and isoprene with a lithium based initiator and wherein said tackifier resin is selected from terpene resins and synthetic hydrocarbon-de~yed ~es~ins of diolef~nlolefin copolymers having a softening point in the range of aoout 70~C., to about 11.5C.
f~
. ~ - 2 -In addition, the present invention prov~des a ,m,ethod ~f p~eparing an adhesive composition which comprises ~) m~xing (1) 1OO parts by weight of a solutlon comprised o~ 100 parts by weight of an unvulcanized block styrene/
isoprene polymer product with molecular weight in the range of 8,000 to 45,000 and overall styrene polymer weight in the range of about 10 to 35 weight percent and a solvent therefor in the range of about 300 to about 1100, prefera'bly about 400 to aboutlOOO,.partsbyweight with (2) about 50 to about 200 parts, preferably about 100 to about 150, by weight of a solution comprised of 100 parts by weight of a tackifying resin for said block polymer product and a solvent therefor in the range of about 25 to about 1100, preferably about 100 to about 1000, parts by weight and (B) optionally removing said solvent from the prepared mixture prior to its application as an adhesive; wherein the total of said solvent(s) is a solvent for the combination of said block polymer and said resin; wherein said block polymer is produced by the process of contacting isoprene and a suitable amount of divinylbenzene under solution polymerization conditions with a polystyryllithium catalyst, said amount of divinylbenzene being from about 0.5/1 to about 10/1, preferably about 0.5/1 to about 3/1, moles of divinylbenzene per mole of active lithium catalyst and wherein said resin has a softening point in the range of about 70C. to about 115 C.
- 2a -gs The (B) option of removing the solvent before appli-cation would be used for hot melt adhesive applications.
For solution adhesive applications, solvent could be retained or the mixture dried and redissolved prior to application.
It is an important feature of this invention that the adhesive composition can be prepared by directly mixing the polymerizates of either or both the block polymer product composed of (A-l) and/or the resin poly-merizate composed of (A-2).
Thus, the adhesive composition can be formed by a method selected from (A) mixing the block polymer poly-merizate ~ith a solution of the solid resin dissolved in its solvent, (B) mixing a solution of the solid block polymer product dissolved in its solvent with a solution of the solid resin dissolved in its solvent, (C) mixing a solution of the solid block polymer dissolved in its solvent with the resin polymerizate or (D) mixing the block polymer polymerizate with the resin polymerizate.
The term polymerizate is intended to refer to a solution of the block polymer produc-t or resin as a direct result of its preparation or polymerization, of its precursor monomers in the presence of its solvent and catalyst, deactivated and optionally removed.
The terms solid block polymer product and solid resin refer to such materials in their recovered form from the polymerizates. When they are dissolved in their solvent they become a solution. It is readily recognized that this solution~forming procedure from the solid prod~ct requires an additional step and effort as compared to the utility and/or convenience of directly using the polymerizate.
In the practice of this invention, the blending or mixing process can be generally accomplished, for example, by using a turbine blade agitation system for a period of about three hours at about 20C. to 30C.
~5~95 The adhesive composition can conveniently be recovered, for example, by application of conventional steam stripping and drying procedures, such as oven drying, to remove solvent.
It was unexpectedly found tha-t by using the solution preparation process of this invention, a resulting adhe-sive composition was observed having increased tack, faster molten solution time and excellent tack retention of the hot melt blend properties as compared to simply dry blending the block polymer product and tackifying resin.
A disclosure of such dry blending can be found in United States Patent No. 4 ,172,860.
In order to effectively provide a solution of the resultant adhesive composition by the method of this invention, it is readily understood that solvents or solvent mixtures are selected in which -the block polymer product and the resin are mutually soluble. For example, the block polymer product is generally soluble in aromatic hydrocarbons such as toluene and benzene as well as some cycloaliphatic hydrocarbons such as cyclohexane, cyclo-pentane and methylcyclopentane. Tackifying resins are also usually soluble in such solvents with some being soluble in aliphatic hydrocarbons and chlorinated aliphatic hydrocarbons. Mixtures of solvents can be used with solubility advantages tailored to both the block polymer and resin. It is generally preferred that the solvent or solvent mixture of the resulting mixed solutions contain about 80 to about 100 weight aliphatic hydrocarbon solvent based on the solvent(s) alone. Thus, the choice of solvent or solvent mixture must depend upon the type of resin used as well as the block polymer product which can readily be determined by one having skill in the art. The term hydrocarbon solvent is intended to refer to liquid hydrocarbons and liquid halo-substituted hydrocarbons.
1~, In the prac-tice of this invention, said tackifier is a resin preferably having a softening point in the range of about 50C to about 150C, preferably about 70C to about 115C, and is preferably selected from at least one of terpene resins and synthetic hydrocarbon derived resins of diolefin/olefin copolymers. Coumerone-indene type resins may be satisfactory. The diolefin/
olefin copolymers are generally of the type prepared by copolymerizing in the presence of a catalyst selected from aluminum chloride or boron trifluoride or boron trifluoride etherate, a mixture of piperylene and at least one olefin containing 4 to 6, preferably 5 to 6, carbon atoms in a diolefin/olefin mole ratio in the range of about 0.6/1 to about 2.5/1, preferably about 0.8/1 to about 1.6/1. Optionally, said copolymer can be modi-fied by copolymerizing therewith about 5 to about 20 weight percent, based on the total monomers, of at least one additional monomer selected from a-methylstyrene and dicyclopentadiene. Some of such resins can have melting points according to ASTM E28-58T less than the required range. However, lower softening resins can be conveniently mixed with higher softening point resins to achieve the required range.
A particularly desirable type of tackifying resin is prepared from piperylene and 2-methyl-2-butene in about 0.8/1 to abou-t a 1.6/1 mole ratio, with the optional inclusion of a-methylstyrene and/or dicyclopentadiene.
Aluminum chloride would be a preferred catalyst In the further practice of this invention, the unvulcanized elastomeric block copolymer (i) preferably has its first polystyrene block with a molecular weight in the range of about 8,000 to about 45,000 with the overall styrene content in the copolymer being in the range of about 10 to about 35 weight percent, preferably 10 to 20 percent.
Additional description o~ a required block copoly-mer (i) for -this invention and methods for its prepara-tion are found in U.S. Patent 3,949,020.
~915~:19~;
In -the block copolymer (i), -the molecular weight of the polystyrene block and the molecular weight of the polydiolefin block can range quite broadly. Also, the weight ratio between the polystyrene and the poly-diolefin can range quite broadly. The polystyreneblock molecular weigh-t can range from about 8,000 to about 45,000. The polydiolefin block molecular weight, ignoring the effect of the divinylbenzene (DVB), can range from about 10,000 to about 100,000. It should be understood that one skilled in the art could adjust these molecular weight limitations and ratios to produce a host of materials ranging from soft, rela-tively weak (tensile at break 500 psi) adhesive sub-strates, through tough thermoplastic elastomers, to plastics. Because these materials are branched, they are more easily processed than their linear counter-parts.
The polystyryllithium catalysts useful in the pre-paration of the block copolymer are those that corres-pond to the formula RLi, in which R is polystyreneprepared by reacting alkyllithium with a styrene monomer solution forming polystyrene with a lithium atom at one end of the styrene chain. The alkyllithiums which can be utilized in the instant invention are n-butyllithium, secondary butyllithium, isopropyllithium, amyllithium, etc. Similarly, substituted styrenes such as p-methyl-styrene, p-t-butylstyrene, or o-ther substituted styrenes may be used in place of styrene, although ~or this invention, generally only styrene is preferred. For instance, if a styrene-isoprene block polymer branched along the polymer chain of the polyisoprene block to other styrene-isoprene units is to be prepared, the n-butyllithium is reacted with a styrene solution to make a polystyryl lithium catalyst which can then be added to an isoprene solution containing the branching agent and polymerizing the isoprene solution until the desired block polymer is formed.
s The polymerization reaction is usually carried out in an inert solvent such as a hydrocarbon. It has been found however that all hydrocarbons will not be particularly conducive. Some hydrocarbons that can be utilized for preparing the copolymer are benzene, toluene, cyclohexane, cyclopentane and me-thyl cyclopentane.
The unvulcanized elastomeric block copolymer (ii) of the linear or radial type which can be used in this inven-tion comprises nonelastomeric terminal styrene polymer blocks having a molecular weight in the range of about 5000 to about 30,000 and internal elastomeric isoprene polymer blocks having a molecular weight in the range of about 50,000 to about 150,000, where the styrene polymer block(s) is about 10 to about 30 weight percent of the copolymer. The characteristics of the internal or middle block, which is elastomeric, might be expressed in ASTM
Special Technical Bulletin No. 18L~ as follows: "A sub-stance that can be stretched at room temperature to at least twice its original length and, after having been stretched and the stress removed, returns with force to approximately its original length in a short time."
The terminal nonelastomeric blocks constitute poly-meric blocks which do not meet this definition. Further-more, the difference between glass transition temperatures f the end blocks and middle blocks should be at least 40C and preferably at least 100C.
Typically, the unvulcanized elastomeric copolymers (i) can be prepared by first polymerizing styrene with a lithium based initiator. A suitable lithium based ini-tiator is, for example, lithium metal, alkyl li-thium com-pounds, lithium hydrocarbyls and organo lithium amides.
The alkyl lithium compounds are preferred. Particularly preferred alkyl lithium compounds are branched chain, preferably secondary alkyl lithiums. Such alkyl lithium compounds especially include secondary butyl lithium, isobutyl lithium, isoamyl lithium and secondary amyl lithium.
~s~s After polymerizing the styrene -to an average molecu-lar weight of from about 2000 to about 100,000, and preferably from about 5000 to about 30,000,isoprene and additional amounts of styrene are added to the poly-meriza-tion mixture.
The polymerization then continues to provide an elas-tomeric middle block isoprene polymer having an average molecular weight of from about 25,000 to about 1,000,000, and more preferably between about 50,000 and about 500,000, followed by a non-elastomeric styrene block polymer to provide the block copolymer effect.
Typically, the preparation of the elastomeric block copolymer is made by polymerizing the monomers at tempera-tures in the order of about -20C. to about 100C., prefer-ably between about 20C. and about 65C. in an inert hydro-carbon solvent such as an alpha olefin or aromatic hydro-carbon. Typically inert hydrocarbon solvents are ali-phatic hydrocarbons (including cycloaliphatic) such as cyclohexane and a typical aromatic hydrocarbon is benzene.
Usually the amount of initiator should be maintained as low as possible, but may be varied over a relatively wide range such as from abou-t 1 to about 200 par-ts per million, based on the weight of the monomers present.
In the practice of this invention, the adhesive com-position is useful for bonding substrates together.Although utility as a solution cast adhesive can be shown, the adhesive composition prepared by this invention has been found to particularly provide an enhanced usefulness in hot melt adhesive applications. Apparently the solu-tion mixing as a method of preparation is an important factor.
The adhesive composition of this invention can ~ suitably bond substrates together such as by simply ; applying it as a hot melt to substrate surfaces and adhering the surfaces together with a thin film of the mixture therebetween. Alternately, it can be applied sl~9s in its solution form. The mixture solution is applied to at least one of the substrate surfaces, followed by at least partially drying it to enhance its tack, bringing -the substrate surfaces together with the application of pressure and drying the adhesive to enhance the bond.
Pressure-sensitive tapes can be prepared by applying a solution of the adhesive composition to a flexible substrate and drying it.
The composition, as a hot melt pressure sensitive adhesive, can be prepared by mixing the block copolymer, tackifying resin, and thermoplastic polymer such as poly-ethylene, polyisobutylene, polystyrene, poly-a-methyl-styrene, ethylene-vinyl acetate copolymers and a minor amount of an oil such as petroleum-derived or coal tar-derived oil such as mineral oil or rubber processing cil.The hot melt adhesive is applied by heating the mixture, applying it to a substrate and cooling.
In the preparation of the adhesives of this invention it is understood that minor amounts of various antioxidant and fillers can be mixed therewith.
The following examples further illustrate the inven-tion and are not intended to be limiting. The parts and percentages are by weight unless otherwise indicated.
Example I
A resin is prepared as follows:
To a reactor is charged 200 parts of heptane and 6 parts of anhydrous aluminum chloride at a temperature of about 25C. While stirring the mixture, 400 parts of a hydrocarbon mixture containing unsaturated hydrocarbons is slowly added to the reactor over a period of about 90 minutes. The temperature of the reaction is maintained at about 25C to 30C for about 60 minutes. The hydro-carbon mixture has the following composition:
5~S
Component Parts
2-pentene 5.3 2-methyl-1-butene 2.3 2-methyl-2-butene 37.5 Isoprene 0.2 1,3-pentadiene (piperylene) 45.0 Cyclopentene 7.5 Unsatura-ted hydrocarbons containing 5 to 6 carbon atoms 2 3 100.1 After the polymerization, 25 parts of water, 8 parts of particulate hydrated calcium hydroxide and 8 parts of Attapulgus clay are added to the polymerizate. Agitation is provided to suspend the hydrated calcium hydroxide at about 90C and continued for about 120 minutes. The mixture is then filtered to remove the insoluble catalyst residue, excess calcium compound and clay. The ~iltrate is then steam distilled to a pot temperature of about 235C. The resulting residual molten resin is poured from the reactor onto an aluminum tray and cooled -to about 25C to form 173 parts of a hard brittle resin having a pale yellow color, and having a softening point, according to ASTM Method E28-58T of about 98C, although it has been observed that softening points in the range f about 950C to about 1010C are generally obtained.
Example II
A styrene/isoprene block copolymer is generally prepared according to the method of Example ~I of U.S.
Patent No. 3,949,020.
Example_III
Adhesives were prepared by solution ~asterbatch according to this invention and by individual blending~
and compared. The tackifying resin was prepared generally according to Example I and the styrene/isoprene block polymer product was prepared according to the general method referred to as Example II.
In the practice of this invention, it is preferable that the polystyrene block has a molecular weight in the range of about 10,000 to about 25,000, based on number average, for hot melt applica-tions.
The solution masterbatch was prepared by blending the unvulcanized block polymer dissolved in solvent with the tackifier dissolved in sQlvent using a turbine blade agitator at about 25Co The masterbatch was mixed for
Example II
A styrene/isoprene block copolymer is generally prepared according to the method of Example ~I of U.S.
Patent No. 3,949,020.
Example_III
Adhesives were prepared by solution ~asterbatch according to this invention and by individual blending~
and compared. The tackifying resin was prepared generally according to Example I and the styrene/isoprene block polymer product was prepared according to the general method referred to as Example II.
In the practice of this invention, it is preferable that the polystyrene block has a molecular weight in the range of about 10,000 to about 25,000, based on number average, for hot melt applica-tions.
The solution masterbatch was prepared by blending the unvulcanized block polymer dissolved in solvent with the tackifier dissolved in sQlvent using a turbine blade agitator at about 25Co The masterbatch was mixed for
3 hours and the adhesive composition recovered in a conventional stripping and drying manner. The adhesive composition was oven dried at a temperature of about 50C. for about 6 hours.
The adhesive composition was applied as a pressure sensitive adhesive by mixing with additional toluene while agitating to form a 33.3 weight percent solution.
The solution was cast on one mil thickness film o~ Mylar (a trademark o~ the E. I. DuPont de Nemours & Co. for a polyester film) which was pulled between two steel rolls at a steady rate which were positioned at approximately a 30J vertical angle to each other for a doctoring ef~èct for the coating. The coated film was oven dried for about 5 minutes at about 70C to form a one mil thickness dry coating on the film.
The same adhesive composition could be applied as a hot melt by first drying to remove solvent and then heating the mass to about 190C-205C, coating the Mylar film therewith and doctoring by pulling the coated film through the rolls which would be heated to about 190C-210C. Thus, the one mil adhesive film coating can be deposited and formed in this manner without the use of solvent.
The individual blending of an adhesive composi tion was accomplished by sequentially mixing toluene with the block polymer product,~ then the tackifying resin and then a small amount of antioxidant to form a solutionO
The solution of the individually blended mixture was applied as a pressure sensitive adhesive by coating 5~9S
it on a one mil Mylar film and doctored by pulling through two rollers which were a-t approximately a 30 vertical angle to each other at a steady rate. The sheet of coated film was oven dried for about 5 minutes at about 70C to form a one mil thickness dry ~ilm coating.
Comparative data of the two types of pressure sensi-tive adhesive compositions is shown in the following Tables 1 and 2. Table 1 relates to the compositions and Table 2 relates to data pertaining to the composi-tions.
The compositions are identified herein as experiments, or compositions, A-D. Experiment D represents the inven-tion utilizing the mixing of individual solutions of block copolymer and -tackifying resin followed by drying the solution mixture. The dried composition was redissolved in toluene and dried to yield the adhesive. The block copolymer was used directly in its polymerizate form where cyclohexane had been used as the polymerization solvent. The tackifying resin had been previously recovered and dried from its polymerizate followed by redissolving it in cyclohexane.
-Compositions A-C were prepared by simply mixing toluene with the dried block polymer, adding the dried resin thereto to form a solution and then drying the solution mixture.
~5~95 Adhesive Compositions A B C D
styrene/isoprene~styrene 56 -_ __ __ block copolymer styrene/isoprene2styrene block copolymer -- 56 -- --styrene/isoprene block copolymer with DVB3 -- -- 56 __ styrene/isoprene block copolymer mixed ~ith tackifying resin4 -- -- -- 100 Tackifying resin5 44 44 44 --Phenolic antioxidant Toluene 200 200 200 200 lObtained as Kraton 1107, trademark of the Shell Chemical Co., reportedly containing 14% styrene end blocks Obtained as Solprene 423-P, trademark of the Phillips Petroleum Co., reportedly containing 15% styrene end blocks 3Prepared generally according to Example II
4Tackifying resin was prepared according to Example I.
Block copolymer was prepared by method of Example II.
The resin was recovered and dried from its polymerizate, then solution mixed with the block polymer polymerizate in its cyclohexane solvent in a copolymer/resin ratio of 56/44 and then dried.
5Prepared according to method of Example I~
~5~S
Table 2 Adhesive Composition Data A B C D
Brookfield Viscosity (c~s) (Spindle No. 2 ~ 840 1105 510 500 Rolling Ball Tack (In.) Initial 2.4 2.9 2.2 1.9 Agedl 2.6 3.1 2.4 1.6 _80 Peel Adhesion (z.l Init~al 53 55 51 48 Aged 54 54 53 48 90 Peel Adhesion ~
Init~al 38 38 38 35 Aged 36 35 38 33 D~namic Shear (psi) Init~al 46 44 41 Aged 38 39 39 37 Te perature to Failure (F) 1000 G/l sq. in. 249 2 199 Solution A~pearance Light Cloudy Light Light Straw Amber Amber Film Appearance Init~al ~ - Off` White Aged ~- Off White UV Exposure~ hrs ~ ry slight discoloratio~
Light Source - 1 -1/2 inches Surface Temperature 92F
E ~ osed Film Tack3 (DAYS) 3 Oven aged for 7 days a-t 70C.
2Probably caused by a partitioning agent 3Number "1" is most observed tack, a~d "VL" is very little observed tack. The observation is a relative value on -the day observed.
EXAMPLE IV
Hot melt pressure sensitive adhesives were prepared by compounding the block copolymers used for the adhesive compositions of A-C of Example III. The dry, mixed copolymer/resin of Compound D of Example III shows the invention. The recipe using the block polymers and Composition D of Example III are shown in Table 3 and identified as AA and DD, respectively.
To prepare the hot melt from block polymers, addi-tional resins, rubber processing oil and ~inc dibutyldithiocarbamate were mixed and the mixture brought to a molten solution. The block polymer was then added.
The hot melt from Compound DD was similarly prepared except that an additional 5 parts of the block polymer 15 product according to Example II and 90 parts of Compound D
described in Example III were mixed together.
The recipes are shown in the following Table 3.
Table 3 HOT MELT PRESSURE SENSITIVE ADSESIVES
AA DD
Tackifying resinl 80 40 Coumarone-Indene resin; 155C.2 25 25 Naphthenic petroleum oil 40 40 Zinc dibutyl dithiocarbamate 3 3 Block copolymer of A, B or C from Example III 55 ~~
Block polymer product of Example II ~- 5 Dried Compound D from Example III -- 90 According to Example I
~0 2Ring and Ball softening poin-t The hot melt solution times are shown in the following Table 4. These times are particularly important because it shows that by prior solution masterbatching the block pol~mer and tackifying resin, the molten solutlon time is reduced. Long molten solution compounds are generally undesirable and typically increase 5~S
1~
preparation of hot melt cos-ts. The molten solution time is the span of time between the addition of the first in ingredient in the recipe of this example until the mixture was a smooth, workable mass.
Table 4 Hot Melt Soluti.on Time , 1 Time to Molten Compound Experiment Solution (minutes)2 C AA L~o lCompounds from Example III.
2Pot temperature about 175-190C.
While certain representative embodiments and details have been shown for the purpose of illustrating the inven-tion, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.
The adhesive composition was applied as a pressure sensitive adhesive by mixing with additional toluene while agitating to form a 33.3 weight percent solution.
The solution was cast on one mil thickness film o~ Mylar (a trademark o~ the E. I. DuPont de Nemours & Co. for a polyester film) which was pulled between two steel rolls at a steady rate which were positioned at approximately a 30J vertical angle to each other for a doctoring ef~èct for the coating. The coated film was oven dried for about 5 minutes at about 70C to form a one mil thickness dry coating on the film.
The same adhesive composition could be applied as a hot melt by first drying to remove solvent and then heating the mass to about 190C-205C, coating the Mylar film therewith and doctoring by pulling the coated film through the rolls which would be heated to about 190C-210C. Thus, the one mil adhesive film coating can be deposited and formed in this manner without the use of solvent.
The individual blending of an adhesive composi tion was accomplished by sequentially mixing toluene with the block polymer product,~ then the tackifying resin and then a small amount of antioxidant to form a solutionO
The solution of the individually blended mixture was applied as a pressure sensitive adhesive by coating 5~9S
it on a one mil Mylar film and doctored by pulling through two rollers which were a-t approximately a 30 vertical angle to each other at a steady rate. The sheet of coated film was oven dried for about 5 minutes at about 70C to form a one mil thickness dry ~ilm coating.
Comparative data of the two types of pressure sensi-tive adhesive compositions is shown in the following Tables 1 and 2. Table 1 relates to the compositions and Table 2 relates to data pertaining to the composi-tions.
The compositions are identified herein as experiments, or compositions, A-D. Experiment D represents the inven-tion utilizing the mixing of individual solutions of block copolymer and -tackifying resin followed by drying the solution mixture. The dried composition was redissolved in toluene and dried to yield the adhesive. The block copolymer was used directly in its polymerizate form where cyclohexane had been used as the polymerization solvent. The tackifying resin had been previously recovered and dried from its polymerizate followed by redissolving it in cyclohexane.
-Compositions A-C were prepared by simply mixing toluene with the dried block polymer, adding the dried resin thereto to form a solution and then drying the solution mixture.
~5~95 Adhesive Compositions A B C D
styrene/isoprene~styrene 56 -_ __ __ block copolymer styrene/isoprene2styrene block copolymer -- 56 -- --styrene/isoprene block copolymer with DVB3 -- -- 56 __ styrene/isoprene block copolymer mixed ~ith tackifying resin4 -- -- -- 100 Tackifying resin5 44 44 44 --Phenolic antioxidant Toluene 200 200 200 200 lObtained as Kraton 1107, trademark of the Shell Chemical Co., reportedly containing 14% styrene end blocks Obtained as Solprene 423-P, trademark of the Phillips Petroleum Co., reportedly containing 15% styrene end blocks 3Prepared generally according to Example II
4Tackifying resin was prepared according to Example I.
Block copolymer was prepared by method of Example II.
The resin was recovered and dried from its polymerizate, then solution mixed with the block polymer polymerizate in its cyclohexane solvent in a copolymer/resin ratio of 56/44 and then dried.
5Prepared according to method of Example I~
~5~S
Table 2 Adhesive Composition Data A B C D
Brookfield Viscosity (c~s) (Spindle No. 2 ~ 840 1105 510 500 Rolling Ball Tack (In.) Initial 2.4 2.9 2.2 1.9 Agedl 2.6 3.1 2.4 1.6 _80 Peel Adhesion (z.l Init~al 53 55 51 48 Aged 54 54 53 48 90 Peel Adhesion ~
Init~al 38 38 38 35 Aged 36 35 38 33 D~namic Shear (psi) Init~al 46 44 41 Aged 38 39 39 37 Te perature to Failure (F) 1000 G/l sq. in. 249 2 199 Solution A~pearance Light Cloudy Light Light Straw Amber Amber Film Appearance Init~al ~ - Off` White Aged ~- Off White UV Exposure~ hrs ~ ry slight discoloratio~
Light Source - 1 -1/2 inches Surface Temperature 92F
E ~ osed Film Tack3 (DAYS) 3 Oven aged for 7 days a-t 70C.
2Probably caused by a partitioning agent 3Number "1" is most observed tack, a~d "VL" is very little observed tack. The observation is a relative value on -the day observed.
EXAMPLE IV
Hot melt pressure sensitive adhesives were prepared by compounding the block copolymers used for the adhesive compositions of A-C of Example III. The dry, mixed copolymer/resin of Compound D of Example III shows the invention. The recipe using the block polymers and Composition D of Example III are shown in Table 3 and identified as AA and DD, respectively.
To prepare the hot melt from block polymers, addi-tional resins, rubber processing oil and ~inc dibutyldithiocarbamate were mixed and the mixture brought to a molten solution. The block polymer was then added.
The hot melt from Compound DD was similarly prepared except that an additional 5 parts of the block polymer 15 product according to Example II and 90 parts of Compound D
described in Example III were mixed together.
The recipes are shown in the following Table 3.
Table 3 HOT MELT PRESSURE SENSITIVE ADSESIVES
AA DD
Tackifying resinl 80 40 Coumarone-Indene resin; 155C.2 25 25 Naphthenic petroleum oil 40 40 Zinc dibutyl dithiocarbamate 3 3 Block copolymer of A, B or C from Example III 55 ~~
Block polymer product of Example II ~- 5 Dried Compound D from Example III -- 90 According to Example I
~0 2Ring and Ball softening poin-t The hot melt solution times are shown in the following Table 4. These times are particularly important because it shows that by prior solution masterbatching the block pol~mer and tackifying resin, the molten solutlon time is reduced. Long molten solution compounds are generally undesirable and typically increase 5~S
1~
preparation of hot melt cos-ts. The molten solution time is the span of time between the addition of the first in ingredient in the recipe of this example until the mixture was a smooth, workable mass.
Table 4 Hot Melt Soluti.on Time , 1 Time to Molten Compound Experiment Solution (minutes)2 C AA L~o lCompounds from Example III.
2Pot temperature about 175-190C.
While certain representative embodiments and details have been shown for the purpose of illustrating the inven-tion, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An adhesive composition which comprises an admixture of an unvulcanized block polymer product and a compatible tackifier resin therefor prepared by the method which comprises mixing (1) 100 parts by weight of a solution com-prised of 100 parts by weight of an unvulcanized block styrene/iosprene polymer product with an overall sytrene polymer content in the range of about 10 to 35 weight percent and a solvent therefor in the range of about 300 to about 1100 parts by weight with (2) about 50 to about 200 parts by weight of a solution comprised of 100 parts by weight of a tackifying resin for said block polymer product and a solvent therefor in the range of about 25 to about 1100 parts by weight, wherein the total of said solvent(s) is a solvent for the combination of said block polymer and said resin; wherein said block polymer is (i) produced by the process of contacting isoprene and a suitable amount of divinylbenzene under solution polymerization conditions with a polystyryllithium catalyst, said amount of divinylbenzene being from about 0.5/1 to about 10/1 moles of divinylbenzene per mole of active lithium catalyst or is (ii) of the linear or radial type styrene/isoprene/styrene block copolymer prepared by sequentially polymerizing styrene and isoprene with a lithium based initiator and wherein said tackifier resin is selected from terpene resins and synthetic hydrocarbon-derived resins of diolefin/olefin copolymers having a softening point in the range of about 70 C., to about 115°C.
2. The adhesive composition of claim 1 where said block polymer product (i) said styrene polymer block has a molecular weight in the range of about 8,000 to about 45,000 and wherein said block polymer product (ii) said styrene polymer blocks have a molecular weight in the range of about 5,000 to about 30,000, said isoprene polymer blocks have a molecular weight in the range of about 50,000 to about 150,000 and where the difference between glass transition temperatures of the end styrene polymer blocks and methyl isoprene polymer blocks is at least 40 C.
3. The adhesive composition of claim 2 formed by a method selected from one of (A) mixing the block polymer polymerizate with a solution of the solid resin dissolved in its solvent, (B) mixing a solution of the solid block polymer product dissolved in its solvent with a solution of the solid resin dissolved in its solvent, (C) mixing a solution of the solid block polymer dissolved in its solvent with the resin polymerizate or (D) mixing the block polymer polymerizate with the resin polymerizate.
4. The adhesive composition of claim 2 with its solvent removed, characterized by having a reduced hot melt solution time as compared to similar composition prepared by dry blending its block polymer and resin components.
5. The adhesive composition of claim 2 where the solvent for the block polymer product is used in an amount of about 400 to about 1000 parts by weight, where the solvent for said tackifying resin is used in an amount of about 100 to about 1000 parts by weight, where the relative amount of divinylbenzene used is about 0.5/1 to about 3/1 moles per mole active lithium catalyst and where said resin has a softning point in the range of about 70°C. to about 115°C.
6. The adhesive composition of claim 2 where said solvent(s) is selected from at least one of toluene, benzene, cyclohexane, cyclopentane and methylcyclo-pentane.
7. A method of preparing an adhesive composition which comprises (A) mixing (1) 100 parts by weight of a solution comprised of 100 parts by weight of an unvulcanized block styrene/isoprene polymer product with molecular weight in the range of 8,000 to 45,000 and overall styrene polymer weight in the range of about 10 to 35 weight percent and a solvent therefor in the range of about 300 to about 1100 parts by weight with (2) about 50 to about 200 parts by weight of a solution comprised of 100 parts by weight of a tackifying resin for said block polymer product and a solvent therefor in the range of about 25 to about 1100 parts by weight and (B) optionally removing said solvent from the prepared mixture prior to its application as an adhesive; wherein the total of said solvent(s) is a solvent for the combination of said block polymer and said resin; wherein said block polymer is produced by the process of contacting isoprene and a suitable amount of divinylbenzene under solution polymerization conditions with a polystyryllithium catalyst, said amount of divinylbenzene being from about 0.5/1 to about 10/1 moles of divinylbenzene per mole of active lithium catalyst and wherein said resin has a softening point in the range of about 70°C. to about 115°C.
8. The method of claim 7 where said tackifier resin is selected from terpene resins and synthetic hydrocarbon-derived resins of diolefin/olefin copolymers having a softening point in the range of about 70°C. to about 115°C.
and wherein in said block polymer product (i) said styrene polymer block has a molecular weight in the range of about 8,000 to about 45,000 and wherein in said block polymer product (ii) said styrene polymer blocks have a molecular weight in the range of about 5,000 to about 30,000, said isoprene polymer blocks have a molecular weight in the range of about 50,000 to about 150,000 and where the difference between glass transition temperatures of the end styrene polymer blocks and methyl isoprene polymer blocks is at least 40°C.
and wherein in said block polymer product (i) said styrene polymer block has a molecular weight in the range of about 8,000 to about 45,000 and wherein in said block polymer product (ii) said styrene polymer blocks have a molecular weight in the range of about 5,000 to about 30,000, said isoprene polymer blocks have a molecular weight in the range of about 50,000 to about 150,000 and where the difference between glass transition temperatures of the end styrene polymer blocks and methyl isoprene polymer blocks is at least 40°C.
9. The method of claim 8 where the method is selected from one of (A) mixing the block polymer polymerizate with a solution of the solid resin dissolved in its solvent, (B) mixing a solution of the solid block polymer product dissolved in its solvent with a solution of the solid resin dissolved in its solvent, (C) mixing a solution of the solid block polymer dissolved in its solvent with the resin polymerizate or (D) mixing the block polymer poly-merizate with the resin polymerizate.
10. The method of claim 8 where the solvent for the block polymer product is used in an amount of about 400 to about 1000 parts by weight, where the solvent for said tackifying resin is used in an amount of about 100 to about 1000 parts by weight, where the relative amount of divinylbenzene used is about 0.5/1 to about 3/1 moles per mole active lithium catalyst and where said resin has a softening point in the range of about 70°C. to about 115°C.
11. The method of claim 8 where said solvent or solvent mixture contains about 80 to about 100 weight percent aliphatic solvent.
12. The method of claim 7 where said solvent(s) is selected from at least one of toluene, benzene, cyclohexane, cyclopentane and methylcyclopentane.
13. The adhesive composition of claims 1 or 2 where said solvent is removed from the prepared mixture prior to its application as an adhesive.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US70,379 | 1979-08-27 | ||
| US06/070,379 US4288567A (en) | 1979-08-27 | 1979-08-27 | Adhesive composition and method of preparation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1145095A true CA1145095A (en) | 1983-04-19 |
Family
ID=22094947
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000354121A Expired CA1145095A (en) | 1979-08-27 | 1980-06-16 | Adhesive composition and method of preparation |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4288567A (en) |
| EP (1) | EP0025004B1 (en) |
| JP (1) | JPS5634778A (en) |
| AU (1) | AU534027B2 (en) |
| BR (1) | BR8005320A (en) |
| CA (1) | CA1145095A (en) |
| DE (1) | DE3070551D1 (en) |
| ZA (1) | ZA804557B (en) |
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| BRPI0720155A2 (en) | 2006-12-07 | 2014-02-04 | 3M Innovative Properties Co | BLOCK COPOLYMER BLENDES AND ACRYLIC ADVISES. |
| KR101768745B1 (en) * | 2014-05-13 | 2017-08-17 | 주식회사 엘지화학 | Non-curable rubber adhesive composition for touch screen panel and non-curable rubber adhesive film for touch screen panel using the same |
| JP6355581B2 (en) * | 2015-03-20 | 2018-07-11 | 住友ゴム工業株式会社 | POLYMER COMPOSITE AND PROCESS FOR PRODUCING THE SAME, TIRE RUBBER COMPOSITION AND PNEUMATIC TIRE |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1140674A (en) * | 1965-03-09 | 1969-01-22 | Dunlop Co Ltd | Method for the manufacture of reinforced polymer compositions in solution |
| GB1277363A (en) * | 1969-03-17 | 1972-06-14 | Goodyear Tire & Rubber | Adhesive composition |
| US3954692A (en) * | 1969-03-17 | 1976-05-04 | The Goodyear Tire & Rubber Company | Adhesive composition |
| US3880953A (en) * | 1969-03-17 | 1975-04-29 | Goodyear Tire & Rubber | Adhesive composition |
| US3784587A (en) * | 1972-07-31 | 1974-01-08 | Goodyear Tire & Rubber | Adhesive composition containing an a-b-a block copolymer,poly alpha-methyl styrene and a tackifying resin |
| US4046838A (en) * | 1972-09-11 | 1977-09-06 | The Goodyear Tire & Rubber Company | Adhesive compositions of a block copolymer and tackifying resin |
| US3949020A (en) * | 1974-09-03 | 1976-04-06 | The Goodyear Tire & Rubber Company | Thermoplastic block polymers |
| JPS51125135A (en) * | 1975-01-22 | 1976-11-01 | Nippon Zeon Co Ltd | Novel adhesive composition |
| US4060503A (en) * | 1975-02-24 | 1977-11-29 | The Goodyear Tire & Rubber Company | Adhesive composition |
| US4038346A (en) * | 1975-03-31 | 1977-07-26 | The Goodyear Tire & Rubber Company | Tackifier composition and rubber mixture |
| US4172860A (en) * | 1976-06-03 | 1979-10-30 | The Goodyear Tire & Rubber Company | Adhesive composition |
| JPS5931547B2 (en) * | 1976-07-27 | 1984-08-02 | 株式会社クラレ | pressure sensitive adhesive composition |
-
1979
- 1979-08-27 US US06/070,379 patent/US4288567A/en not_active Expired - Lifetime
-
1980
- 1980-06-16 CA CA000354121A patent/CA1145095A/en not_active Expired
- 1980-07-28 ZA ZA00804557A patent/ZA804557B/en unknown
- 1980-07-31 AU AU60954/80A patent/AU534027B2/en not_active Ceased
- 1980-08-22 BR BR8005320A patent/BR8005320A/en unknown
- 1980-08-22 EP EP80630035A patent/EP0025004B1/en not_active Expired
- 1980-08-22 DE DE8080630035T patent/DE3070551D1/en not_active Expired
- 1980-08-26 JP JP11765080A patent/JPS5634778A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| AU534027B2 (en) | 1983-12-22 |
| AU6095480A (en) | 1981-03-05 |
| JPS5634778A (en) | 1981-04-07 |
| EP0025004A1 (en) | 1981-03-11 |
| EP0025004B1 (en) | 1985-04-24 |
| DE3070551D1 (en) | 1985-05-30 |
| ZA804557B (en) | 1981-09-30 |
| US4288567A (en) | 1981-09-08 |
| BR8005320A (en) | 1981-03-04 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |