CN110194940B

CN110194940B - Hot melt pressure sensitive adhesive composition and method of making same

Info

Publication number: CN110194940B
Application number: CN201810159453.7A
Authority: CN
Inventors: 秦永胜; 林春雷; 李立
Original assignee: HB Fuller Co
Current assignee: HB Fuller Co
Priority date: 2018-02-26
Filing date: 2018-02-26
Publication date: 2022-04-15
Anticipated expiration: 2038-02-26
Also published as: WO2019165396A1; CN110194940A

Abstract

A hot melt pressure sensitive adhesive composition comprising an isocyanate group-terminated compound, a plasticizer, a thermoplastic polymer, and a tackifier. At least one of the plasticizer or tackifier is hydroxyl modified.

Description

Hot melt pressure sensitive adhesive composition and method of making same

Technical Field

The present disclosure relates to hot melt adhesive compositions and methods of forming the same. In particular, the present disclosure relates to pressure sensitive hot melt adhesive compositions and methods of forming the same.

Background

Hot melt adhesive compositions are used in a variety of applications where it is desirable to bond two substrates together. Hot melt adhesive compositions are typically applied in a liquid or molten state and form a bond as they cool and solidify. The hot melt adhesive composition may be applied by extruding the adhesive composition directly onto a substrate at an elevated temperature to form a structural bond with another substrate as the temperature of the adhesive composition cools.

The hot melt adhesive compositions are useful in packaging applications (e.g., for bonding paperboard and corrugated board), in nonwoven applications (e.g., disposable articles such as diapers), bookbinding, and footwear manufacture, among others.

In certain applications, hot melt adhesives with pressure sensitive properties are desired. In certain applications, there is a need for hot melt adhesives that are pressure sensitive and that exhibit adhesion to a wide range of substrates in a wide range of applications. In certain applications, there is a need for hot melt adhesives that are pressure sensitive and exhibit excellent retention at elevated temperatures.

Disclosure of Invention

Various aspects of the present disclosure provide a hot melt pressure sensitive adhesive composition. In a first aspect, the hot melt pressure sensitive adhesive comprises an isocyanate group-terminated compound, a plasticizer, a thermoplastic polymer, and a tackifier. At least one of the plasticizer or tackifier comprises isocyanate reactive groups. In some aspects, the hot melt pressure sensitive adhesive composition of the first aspect further comprises a polyurethane curing catalyst. In some aspects, the hot melt pressure sensitive adhesive composition further comprises a non-reactive tackifier.

In some aspects, the plasticizer and tackifier both comprise hydroxyl groups. In some aspects, the hot melt pressure sensitive adhesive composition comprises a second plasticizer that is not modified by hydroxyl groups.

In some aspects, the combined weight percentage of the isocyanate-terminated compound, plasticizer, thermoplastic polymer, and tackifier is at least 90%, based on the total weight of the adhesive composition. In some aspects, the combined weight percentage of the isocyanate-terminated compound, plasticizer, thermoplastic polymer, and tackifier is at least 95%, based on the total weight of the adhesive composition.

In some aspects, the tackifier is at least one of an aliphatic hydrocarbon resin, an aromatic hydrocarbon resin, or an aliphatic-aromatic hydrocarbon resin. In some aspects, the tackifier is at least one of an aliphatic resin, an aromatic modified resin, a cycloaliphatic resin, a hydroxyl modified resin, or a hydrogenated version thereof. In some aspects, the tackifier is at least one of a rosin or a terpene resin.

In some aspects, the thermoplastic polymer is at least one of a block copolymer or a polyolefin. In some aspects, the thermoplastic polymer is at least one of a propylene-rich polyolefin, a butene-rich polyolefin, or an ethylene-rich polyolefin. In some aspects, the thermoplastic polymer can be a styrenic block copolymer. In some aspects, the thermoplastic polymer is an SIS block copolymer.

In some aspects, the plasticizer is at least one of an oil, a liquid resin, or a liquid polymer. In some aspects, the plasticizer is polybutene. In some aspects, the hot melt pressure sensitive adhesive composition comprises a first plasticizer that is free of hydroxyl groups and is at least one of an oil, a liquid resin, or a liquid polymer, and a second plasticizer comprising hydroxyl groups.

In some aspects, the isocyanate-terminated compound may be a monomeric diisocyanate. In some aspects, the isocyanate group-terminated compound may be at least one of methylene diphenyl diisocyanate (MDI), methylene diphenyl isocyanate, Hydrogenated Methylene Diphenyl Isocyanate (HMDI), Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), polymeric methylene diphenyl diisocyanate, Toluene Diisocyanate (TDI), polymethylene polyphenyl diisocyanate, Naphthalene Diisocyanate (NDI), or polymethylene polyphenyl isocyanate (PAPI).

In some aspects, the hot melt pressure sensitive adhesive composition is tacky at room temperature.

In some aspects, the isocyanate-terminated compound is present in an amount of about 1 to about 20 weight percent based on the total weight of the hot melt pressure sensitive adhesive composition. In some aspects, the thermoplastic polymer is present in an amount of about 5 to about 70 weight percent, based on the total weight of the hot melt pressure sensitive adhesive composition. In some aspects, the tackifier is present in an amount of greater than 0.0 wt% to about 50 wt%, based on the total weight of the hot melt pressure sensitive adhesive composition. In some aspects, the tackifier is present in an amount of about 5 to about 30 weight percent, based on the total weight of the hot melt pressure sensitive adhesive composition. In some aspects, the plasticizer is present in an amount of greater than 0.0 wt% to about 50 wt%, based on the total weight of the hot melt pressure sensitive adhesive composition.

In some aspects, the hot melt pressure sensitive adhesive composition comprises an isocyanate-terminated compound in an amount of about 5 to about 20 weight percent, a thermoplastic polymer in an amount of about 15 to about 40 weight percent, a tackifier in an amount of about 10 to about 50 weight percent, a plasticizer in an amount of about 15 to about 30 weight percent, and a polyurethane cure catalyst in an amount of about 0.2 weight percent, all based on the total weight of the hot melt pressure sensitive adhesive composition.

Also disclosed herein in a second aspect is a hot melt pressure sensitive adhesive composition comprising the reaction product of an isocyanate compound, a plasticizer, and a tackifier; and a thermoplastic polymer. At least one of the plasticizer or tackifier is hydroxyl terminated.

In some aspects, the isocyanate compound is at least one of an aromatic diisocyanate, an aliphatic diisocyanate, or an oligomer; the thermoplastic polymer is at least one of styrene-ethylene-butylene-styrene (SEBS), styrene-isoprene-styrene (SIS) or styrene-butadiene-styrene (SBS); the tackifier is rosin, terpene resin, phenolic resin or terpene phenolic resin; the plasticizer is at least one of mineral oil, resin or liquid polymer.

In some aspects, the hot melt pressure sensitive adhesive composition of the second aspect comprises an isocyanate compound in an amount of about 5 to about 20 weight percent, a thermoplastic polymer in an amount of about 15 to about 40 weight percent, a tackifier in an amount of about 10 to about 40 weight percent, a plasticizer in an amount of about 15 to about 25 weight percent, and a polyurethane curing catalyst in an amount of about 0.2 weight percent, all based on the total weight of the hot melt pressure sensitive adhesive composition.

In some aspects, the tackifier has a softening point of from about 60 to about 160 ℃. In some aspects, the tackifier has at least one of a number average molecular weight of about 100 to about 1000, an OH number of about 1 to about 400, or a softening point of about 60 to about 160 ℃.

In some aspects, the hot melt pressure sensitive adhesive composition has a 180 ° peel strength of at least 5N/cm (13N/inch) after curing.

In some aspects, the hot melt pressure sensitive adhesive composition has at least 23N/cm after curing²(150N/inch)²) The shear strength of (2).

In some aspects, the hot melt pressure sensitive adhesive composition has a hold time (holding time) of greater than 1 minute at a temperature greater than 40 ℃ for about one week after curing.

In some aspects, the hot melt pressure sensitive adhesive composition exhibits cross-linking between the components of the hot melt pressure sensitive adhesive composition upon curing.

Also disclosed herein is a method of forming a hot melt pressure sensitive adhesive composition. In some aspects, the method includes combining a thermoplastic polymer, a plasticizer, and a tackifier to form a first mixture, and adding an isocyanate compound to the first mixture to form a hot melt pressure sensitive adhesive composition. In some aspects, the combined weight percentage of the thermoplastic polymer, plasticizer, tackifier, and isocyanate compound is at least 90 weight percent, based on the total weight of the hot melt pressure sensitive adhesive composition. At least one of the plasticizer or tackifier contains-OH groups. In some aspects, the method further comprises adding a catalyst.

In some aspects, the method includes maintaining the thermoplastic polymer, plasticizer, and hydroxyl containing tackifier at a first temperature during the combining step, and performing the adding step at a second temperature that is lower than the first temperature. In some aspects, during the combining step, the thermoplastic polymer, plasticizer, and hydroxyl containing tackifier are at a first temperature of about 100 to about 200 ℃. In some aspects, the adding step is performed at a second temperature of about 80 to about 130 ℃.

In some aspects, the method further comprises maintaining the sub-atmospheric pressure on the thermoplastic polymer, plasticizer, and hydroxyl containing tackifier for about 2 to about 3 hours. In some aspects, the method comprises maintaining a pressure of less than or equal to-1.0 MPa relative to atmospheric pressure over the thermoplastic polymer, plasticizer, and hydroxyl containing tackifier for about 2 to about 3 hours. In some aspects, the adding step comprises maintaining the sub-atmospheric pressure for about 0.5 to about 2 hours. In some aspects, the method comprises maintaining a pressure of less than or equal to-1.0 MPa relative to atmospheric pressure for about 0.5 to about 2 hours during the adding step.

While multiple embodiments are disclosed, other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Brief Description of Drawings

Fig. 1 is a graph showing thermal history vs. temperature experimental results for various compositions of embodiments described herein, where the time of the total thermal history is expressed in seconds(s), minutes (min), and hours (h), and the dashed line in the graph is the temperature line.

Detailed Description

Disclosed herein is a hot melt adhesive composition which exhibits thermal stability, green bond strength (green bond strength), pot stability (pot stability), cured adhesive strength, and can be used in a wide range of applications in production and use. The hot melt pressure sensitive adhesive composition exhibits cross-linking between the components of the hot melt pressure sensitive adhesive composition after curing. This crosslinking helps to provide a hot melt pressure sensitive adhesive composition with excellent retention at elevated temperatures.

The adhesive composition has a suitable green strength (green strength) to form an initial bond with a substrate. The hot melt pressure sensitive adhesive compositions disclosed herein exhibit adhesion to substrates formed from a wide range of materials. Some examples of materials to which the hot melt pressure sensitive adhesive composition exhibits good adhesion include, but are not limited to, Polycarbonate (PC), polypropylene (PP), Polyethylene (PE), polyethylene terephthalate (PET), Acrylonitrile Butadiene Styrene (ABS), polyvinyl chloride (PVC), and Polyamide (PA), although other materials are further contemplated. The hot melt pressure sensitive adhesive compositions disclosed herein exhibit good tack, cohesive strength (adhesive strength), peel strength, and holding power to substrates formed from the materials disclosed herein.

The hot melt pressure sensitive adhesive composition is tacky to the touch at room temperature. As used herein, "pressure sensitive" refers to the property of a material to be tacky at room temperature. The hot melt pressure sensitive adhesive may be tacky to the touch after application and cooling to room temperature. The adhesive composition may be tacky to the touch both before the hot melt pressure sensitive adhesive composition is cured and after the adhesive composition is cured. The hot melt pressure sensitive adhesive composition may solidify or solidify when the liquid adhesive composition is cooled from its application temperature to room temperature (e.g., 25-35 ℃) and forms a bond between the components of the adhesive composition. As used herein, "tacky" or "stickiness" describes the property of a material (e.g., an adhesive composition) to adhere to a substrate after contact with the substrate. For example, an adhesive composition disposed on a surface of a first substrate can be adhered to a second substrate that is in contact with an adhesive material adhered to the first substrate such that the amount of force required to separate the first substrate from the second substrate is greater than the force required to separate the first substrate from the second substrate in the absence of the adhesive material therebetween.

The hot melt pressure sensitive adhesive composition solidifies after it has cooled to room temperature (about 25 to about 35 ℃). After curing, the hot melt pressure sensitive adhesive composition exhibits a 180 ° peel strength from about 3.9N/cm (10N/inch), about 5.9N/cm (15N/inch), about 7.9N/cm (20N/inch), or about 9.8N/cm (25N/inch) to about 21.7N/cm (55N/inch), about 23.6N/cm (60N/inch), about 25.6N/cm (65N/inch), or about 27.6N/cm (70N/inch), or a 180 ° peel strength between any pair of the foregoing values. For example, the hot melt pressure sensitive adhesive composition exhibits a 180 ° peel strength between any pair of the foregoing values after being held in a CTH (constant temperature and humidity) chamber for about one week. In some embodiments, the hot melt pressure sensitive adhesive composition has a 180 ° peel strength of greater than 10.2N/cm (26N/inch) after curing. In some embodiments, the hot melt pressure sensitive adhesive composition has a 180 ° peel strength of at least 25.6N/cm (65N/inch) after curing.

The hot melt pressure sensitive adhesive composition has from about 10N/cm after curing²(65N/inch)²) About 15N/cm²(95N/inch)²) About 51.2N/cm²(330N/inch)²) About 52.7N/cm²(340N/inch)²) About 54.3N/cm²(350N/inch)²) Or about 55.8N/cm²(360N/inch)²) To about 60.5N/cm²(390N/inch)²) About 62.0N/cm²(400N/inch)²) About 63.6N/cm²(410N/inch)²) About 75N/cm²(484N/inch)²) Or about 100N/cm²(645N/inch)²) Or a shear strength between any pair of the foregoing values. In some embodiments, the hot melt pressure sensitive adhesive composition has greater than 22.9N/cm after curing²(148N/inch)²) The shear strength of (2). In some embodiments, the hot melt pressure sensitive adhesive composition has at least 63.1N/cm after curing²(407N/inch)²) The shear strength of (2).

The hot melt pressure sensitive adhesive composition exhibits thermal stability over a wide temperature range. The hot melt pressure sensitive adhesive composition exhibits a hold time of greater than 1 (one) minute at a temperature of about 40 ℃ for about one week after application. In some embodiments, the hot melt pressure sensitive adhesive composition exhibits a hold time of from about 1 (one) minute, about 10 minutes, or about 20 minutes to about 30 minutes or about 40 minutes, or a time between any pair of the foregoing values, at a temperature of up to 60 ° after about one week of curing. In some embodiments, the hot melt pressure sensitive adhesive composition exhibits a hold time of from about 1 (one) minute, about 40 minutes, or about 1 (one) hour to about 2 (two) hours, about 3 (three) hours, or about 4 (four) hours, or a time between any pair of the foregoing values, at a temperature of up to 75 ℃ after about one week of curing. In some embodiments, the hot melt pressure sensitive adhesive composition exhibits a hold time of greater than about 40 minutes at a temperature of about 60 ℃ after about one week of curing. In some embodiments, the hot melt pressure sensitive adhesive composition exhibits a hold time of greater than 4 hours at a temperature of about 75 ℃ after about one week of curing. In some embodiments, the hot melt pressure sensitive adhesive composition exhibits absolute retention at temperatures up to about 100 ℃ after about one week of curing. For example, the adhesive composition does not fail in adhesion at temperatures up to 100 ℃ after about one week of curing. In some embodiments, the hot melt pressure sensitive adhesive composition exhibits absolute holding power over a range of temperatures. For example, the bond of the adhesive composition remains after about one week of curing at temperatures up to 40 ℃, then at temperatures up to 60 ℃, then at temperatures up to 75 ℃, and then at temperatures up to 100 ℃ without failing.

The hot melt pressure sensitive adhesive composition exhibits viscosity stability over a wide temperature range. For example, the adhesive composition maintains viscosity stability at temperatures up to about 120 ℃, about 130 ℃, about 140 ℃, or about 150 ℃. In some embodiments, the hot melt pressure sensitive adhesive composition has a viscosity increase of no greater than about 0.8%/hour, no greater than about 0.9%/hour, or no greater than about 1.0%/hour at a temperature of about 150 ℃. In some embodiments, the hot melt pressure sensitive adhesive composition has a viscosity increase of less than about 6%/hour at a temperature of about 150 ℃. In some cases, the hot melt pressure sensitive adhesive composition has a viscosity of no greater than about 21,000 centipoise (cp), no greater than about 20,000cp, no greater than about 19,000cp, no greater than about 8,000cp, no greater than about 7,500cp, no greater than about 7,000cp, no greater than about 3,000cp, no greater than about 2,900cp, or no greater than about 2,800cp at a temperature of about 150 ℃.

The hot melt pressure sensitive adhesive composition includes a thermoplastic polymer, an isocyanate compound, a tackifier, and a plasticizer. The hot melt pressure sensitive adhesive composition may comprise the reaction product of an isocyanate compound and a tackifier and/or plasticizer, and a thermoplastic polymer having sufficient structural integrity to provide cohesive strength. In some embodiments, the hot melt pressure sensitive adhesive composition comprises one or more of the individual components. For example, the adhesive composition may comprise one or more isocyanate-terminated compounds, one or more thermoplastic polymers, one or more tackifiers, and/or one or more plasticizers. In some embodiments, the hot melt pressure sensitive adhesive composition further comprises other components, such as a catalyst and/or an antioxidant. In some embodiments, the hot melt pressure sensitive adhesive comprises no greater than 15 wt.%, no greater than 10 wt.%, no greater than 5 wt.%, or even no thereof, of a polyester or polyether polyol.

Thermoplastic polymers

The hot melt pressure sensitive adhesive composition comprises one or more thermoplastic polymers combined with the remaining components of the adhesive composition to provide initial green strength and cured strength to the adhesive composition. In some embodiments, the thermoplastic polymer is at least one of a homopolymer, a copolymer, or a higher order polymer. For example, the thermoplastic polymer may be a block copolymer and/or terpolymer. The thermoplastic polymer may be an elastomer.

In some embodiments, the thermoplastic polymer has a softening point of a temperature from about 60 ℃, about 70 ℃, about 80 ℃, or about 90 ℃ to about 160 ℃, about 170 ℃, about 180 ℃, or about 190 ℃ (as measured by the ASTM ring and ball softening point test), or a temperature between any pair of the foregoing values, although thermoplastic polymers having other softening points are contemplated.

Suitable polymers from which the thermoplastic polymer may be formed include, but are not limited to, block copolymers such as A-B diblock copolymers, A-B-A triblock copolymers, radial A-B block copolymers, multiblock copolymers, Y block copolymers, linear A- (B-A)_n-B block copolymers, or amorphous or semi-crystalline polyolefin polymers.

In some embodiments, such as A-B-A block copolymers, radial A-B block copolymers, or linear A- (B-A)_nIn the B block copolymer, the A component may comprise a polystyrene block and the B component may comprise a rubber block (e.g., a polyolefin block). Other suitable A components include polymers having aromatic monomers and glassy end block units such as poly alpha-methylstyrene and other similar polymers. Suitable B components include, but are not limited to, polymers or monomers that can produce rubbery polymer blocks, such as isoprene, butadiene, and mixtures thereof. Suitable B components may include hydrogenated and/or unhydrogenated polymers or monomers. Suitable block copolymers from which the thermoplastic polymer may be formed include styrene block copolymers including, but not limited to, styrene-ethylene-butylene-styrene (SEBS), styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR), or hydrogenated SIS (seps), and combinations thereof.

Suitable block copolymers from which the thermoplastic polymer can be formed include styrenic block copolymers comprising from about 10%, about 15%, or about 20% to about 40%, about 45%, or about 50%, or a weight percentage of styrene between any pair of the foregoing values, based on the total weight of the block copolymer. Suitable examples of block copolymers from which the thermoplastic polymer may be formed include styrene-isoprene-styrene (SIS) block copolymers having a number average molecular weight of from about 50,000, about 70,000, or about 90,000 to about 150,000, about 180,000, about 200,000, or about 500,000 and comprising from about 10 wt%, about 15 wt%, or about 20 wt% to about 40 wt%, about 50 wt%, or about 60 wt% styrene, based on the total weight of the copolymer. Other suitable examples of block copolymers from which the thermoplastic polymer may be formed include styrene-butadiene-styrene (SBS) block copolymers having a molecular weight of from about 50,000, about 70,000, or about 90,000 to about 150,000, about 180,000, or about 200,000, or about 500,000 and comprising from about 10 wt%, about 15 wt%, or about 20 wt% to about 40 wt%, about 50 wt%, or about 60 wt% styrene. Other suitable examples of block copolymers from which the thermoplastic polymer may be formed include styrene-hydrogenated butadiene-styrene block copolymers (i.e., styrene-ethylene-butylene-styrene block copolymers) having a molecular weight of from about 30,000, about 50,000, or about 70,000 to about 90,000, about 100,000, or about 120,000, or about 500,000 and comprising from about 10 wt%, about 15 wt%, or about 20 wt% to about 40 wt%, about 50 wt%, or about 60 wt% styrene, although other block copolymers of other molecular weights and compositions are contemplated. In some embodiments, the thermoplastic polymer may comprise a copolymer blend having a ratio of diblock polymer to triblock polymer, or a ratio between any pair of the foregoing values, of from 0.1:1, about 0.2:1, about 0.3:1, to about 0.8:1, about 0.9:1, or 1: 1.

Other examples of suitable thermoplastic polymers include polybutadiene, including hydroxylated forms thereof, such as hydroxyl-terminated polybutadiene. Other examples of other suitable thermoplastic polymers include polyolefins. For example, the thermoplastic polymer can be at least one of a propylene-rich polyolefin, a butene-rich polyolefin, or an ethylene-rich polyolefin. It is contemplated that in some embodiments, suitable thermoplastic polymers may include acrylates or acetates (e.g., EVA).

Examples of suitable commercially available thermoplastic polymers include styrenic block copolymers such as those sold under the product names SIS 1105 or SIS 1124 (both available from Guingzhou Tongshen Chemical Co., Cantonese, China), KRATON D1126, or other styrenic block copolymers sold under the tradenames KRATON and KRATON G (available from Kraton Corp., Houston, TX). Examples of suitable olefin block copolymers include those sold under The trade name INFUSE (available from The Dow Chemical Co., located in Midland, MI). Examples of suitable propylene-rich polyolefins include VISTAMAXX 6202 (ex xonmobil Chemical Company, Houston, TX).

The thermoplastic polymer is present in the hot melt pressure sensitive adhesive composition in an amount from about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, or about 25 wt% to about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, or about 70 wt%, or in an amount between any pair of the foregoing values, based on the total weight of the hot melt pressure sensitive adhesive composition, although other amounts are contemplated. In embodiments having more than one thermoplastic polymer, the total amount of the more than one thermoplastic polymer in the hot melt pressure sensitive adhesive composition can be from about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, or about 25 wt% to about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, or about 70 wt%, or an amount between any pair of the foregoing values, based on the total weight of the hot melt pressure sensitive adhesive composition, although other amounts are contemplated.

Isocyanate compound

The hot melt pressure sensitive adhesive composition comprises one or more isocyanate compounds. The term "isocyanate compound" as used herein means a compound having 2 or more-NCO groups. The isocyanate compound may be an isocyanate group-terminated compound. The isocyanate compound may be selected from monomeric isocyanates and isocyanate-terminated oligomers.

Some examples of suitable isocyanate compounds include, but are not limited to, aromatic isocyanates such as aromatic diisocyanates, aliphatic isocyanates such as aliphatic diisocyanates. In some examples, isocyanate compounds may be used to form a prepolymer composition for use in the hot melt pressure sensitive adhesive.

Suitable isocyanate compounds that may be used in forming the hot melt pressure sensitive adhesive composition include aliphatic and aromatic isocyanate compounds having an isocyanate functionality of about 2 or greater. In some embodiments, the isocyanate compound has 1 to 10 aliphatic or aromatic groups substituted with an isocyanate group. The isocyanate compound may also include other substituents that do not substantially adversely affect the viscosity of the isocyanate prepolymer, the adhesive properties of the hot melt pressure sensitive adhesive composition, or the reactivity of the-NCO groups during formation of the adhesive composition. The isocyanate compound may also include mixtures of both aromatic and aliphatic isocyanates as well as isocyanate compounds having both aliphatic and aromatic character.

Suitable isocyanate compounds include methylene diphenyl isocyanate compounds such as diphenylmethane diisocyanate (including isomers thereof), methylene diphenyl diisocyanate (MDI), carbodiimide-modified MDI, Hydrogenated Methylene Diphenyl Isocyanate (HMDI), Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), polymeric methylene diphenyl isocyanate, diphenylmethane-4, 4' -diisocyanate, diphenylmethane-2, 2' -diisocyanate, diphenylmethane-2, 4' -diisocyanate and other oligomeric methylene isocyanates, toluene diisocyanate compounds (TDI) (including isomers thereof), tetramethylxylene diisocyanate (TMXDI), isomers of naphthalene diisocyanate, isomers of triphenylmethane triisocyanate, and mixtures thereof, however, other isocyanates are further contemplated. In some cases, aliphatic diisocyanates, triisocyanates and polyisocyanates are also suitable isocyanate compounds, including, for example, hydrogenated aromatic diisocyanates, aliphatic polyisocyanates or cycloaliphatic polyisocyanates, although other isocyanates are further contemplated.

The isocyanate compound is present in the hot melt pressure sensitive adhesive composition in an amount of from about 1 weight percent, about 2 weight percent, about 4 weight percent, about 6 weight percent to about 14 weight percent, about 16 weight percent, about 18 weight percent, or about 20 weight percent, or an amount between any pair of the foregoing values, based on the total weight of the hot melt pressure sensitive adhesive composition, although other values are contemplated. In embodiments having more than one isocyanate compound, the total amount of isocyanate compound present in the hot melt pressure sensitive adhesive composition can be from about 1 weight percent, about 2 weight percent, about 4 weight percent, about 6 weight percent to about 14 weight percent, about 16 weight percent, about 18 weight percent, or about 20 weight percent, or an amount between any pair of the foregoing values, based on the total weight of the hot melt pressure sensitive adhesive composition, although other values are contemplated. In some embodiments, the isocyanate compound is present in the hot melt pressure sensitive adhesive composition in an amount of about 5 weight percent, about 10 weight percent, or about 15 weight percent based on the total weight of the hot melt pressure sensitive adhesive composition, although other amounts are contemplated.

Tackifier

The hot melt pressure sensitive adhesive composition comprises one or more tackifiers. In some embodiments, suitable tackifiers for use in the adhesive composition are those that contain isocyanate-reactive groups (i.e., active hydrogen-containing groups such as hydroxyl, amine, mercapto, etc.) that are reactive with the isocyanate component of the hot melt pressure sensitive adhesive composition. In some embodiments, the hot melt pressure sensitive adhesive composition may further comprise one or more non-reactive tackifiers.

Suitable tackifiers that can be used to form the adhesive composition include those having a softening point (as measured by the ASTM ring and ball softening point test) of a temperature of from about 60 to about 160 ℃. For example, suitable tackifiers may have a softening point greater than 60 ℃ and less than about 160 ℃, less than about 150 ℃, or less than about 140 ℃. In some cases, tackifiers suitable for use in forming the adhesive composition have a softening point of from about 60 ℃, about 80 ℃, about 100 ℃ to about 120 ℃, about 140 ℃, or about 160 ℃, or a softening point between any pair of the foregoing temperatures, although other tackifiers are further contemplated.

In some embodiments, the tackifier has a number average molecular weight of from about 80, about 100, or about 120 to about 900, about 1000, or about 1100, or a molecular weight between any pair of the foregoing values, although other molecular weights are contemplated.

In some embodiments, the tackifier is a hydroxyl modified tackifier (-OH modified tackifier), such as a hydroxyl terminated tackifier. In some embodiments, the tackifier has a hydroxyl (OH) value of from about 1, about 5, about 10, about 15, about 20, about 25, about 30, about 50 to about 100, about 140, about 160, about 200, about 250, about 300, about 380, about 400, or about 420, or an OH value between any pair of the foregoing values.

Suitable tackifiers for use in forming the hot melt pressure sensitive adhesive composition include aromatic, aliphatic, and cycloaliphatic hydrocarbon resins, mixed aromatic and aliphatic modified hydrocarbon resins, hydroxyl modified resins, aromatic modified aliphatic hydrocarbon resins, and hydrogenated versions thereof. Other suitable examples of tackifiers include terpenes, modified terpenes, and hydrogenated versions thereof.

In some embodiments, suitable tackifiers include rosin, terpene resins, phenolic resins (e.g., terpene phenolic resins, phenol-modified aromatic hydrocarbon resins, and the like), and hydrogenated versions thereof. In some embodiments, suitable tackifiers include natural rosins, modified rosins, rosin esters, and hydrogenated versions thereof; low molecular weight polylactic acid, and combinations thereof. Examples of suitable natural and modified rosins include rosin gum, wood rosin, tall oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin, and polymerized rosin. Examples of suitable tackifiers include rosin esters including glycerol esters of rosin, methyl esters of rosin, glycerol esters of hydrogenated rosin, glycerol esters of polymerized rosin, pentaerythritol esters of natural and modified rosins including pentaerythritol esters of rosin, pentaerythritol esters of hydrogenated rosin, pentaerythritol esters of tall oil rosin, phenol-modified pentaerythritol esters of rosin, and combinations thereof.

Other examples of suitable tackifiers include copolymers and terpolymers of natural terpenes, such as styrene-terpene, alpha-methylstyrene-terpene, and vinyltoluene-terpene, and combinations thereof. Examples of suitable aliphatic and cycloaliphatic petroleum hydrocarbon resins include aliphatic and cycloaliphatic petroleum hydrocarbon resins, hydrogenated derivatives thereof, and combinations thereof. Suitable aliphatic and cycloaliphatic petroleum hydrocarbon resins include, for example, branched, unbranched, and cyclic C5 resins, C9 resins, and C10 resins.

Examples of suitable commercially available tackifiers that can be used to form the hot melt pressure sensitive adhesive composition include those sold under various trade names, including trade nameESCOREZ^TMSome of the series (obtained from ExxonMobil Chemical Co, located in Houston, TX), including ESCOREZ 5400, ESCOREZ 5415, ESCOREZ 5600, ESCOREZ 5615, and ESCOREZ 5690; trade name EASTOTAC^TMSeries (available from Eastman Chemical Co., located in Kingsport, TN) including EASTOTAC H-100R, EASTOTAC H-100L, EASTOTAC H130W and EASTOTAC H142; trade name

Series (obtained from Cray Valley HSC located in Exton, PA) including WINGTACK 86, WINGTACK EXTRA and WINGTACK 95; trade names PICCOTAC series (available from Eastman Chemical Co.), including PICCOTAC 8095; trade name of ARKON^TMSeries (obtained from Arkawa Europe GmbH, Germany) including ARKON P-125; and under the trade name REGALITE^TMThose sold in series (available from Eastman Chemical Co.) include, for example, REGALITE R1125.

Suitable tackifiers for use in forming the hot melt pressure sensitive adhesive composition include phenolic-modified terpene resins, such as, for example, SYLVARES^TMThose sold by TP (KRATON Corp. ex Houston, TX) and phenol-modified C9 aromatic hydrocarbon resins, such as those sold under the tradename HIKOTACK P (available from Kolon Chemical Company LTD, located in Kwachen City, Korea). Other suitable tackifiers that may be used to form the hot melt pressure sensitive adhesive composition include modified aliphatic resins, such as those sold under the trade name LUHOREZ^TMM90 (obtained from Zibo Luha Hongjin New Material Co., Ltd., of Zibo, China).

The tackifier is present in the hot melt pressure sensitive adhesive composition in an amount of from about 1 wt%, about 5 wt%, about 10 wt%, or about 15 wt% to about 30 wt%, about 40 wt%, about 50 wt%, or about 60 wt%, based on the total weight of the adhesive composition, or in an amount between any pair of the foregoing values, although other values are contemplated. In some embodiments, the one or more tackifiers are present in the hot melt pressure sensitive adhesive composition in an amount of about 10 weight percent, about 12 weight percent, or about 20 weight percent based on the total weight of the hot melt pressure sensitive adhesive composition, although other weight percentages are contemplated.

Plasticizer

The hot melt pressure sensitive adhesive composition comprises one or more plasticizers. In some embodiments, the plasticizer is at least one of an oil, a liquid resin, or a liquid polymer. Liquid resins include resins that are liquid at room temperature (e.g., about 25 to about 35 ℃).

Suitable plasticizers for forming the hot melt pressure sensitive adhesive composition include mineral oils, paraffin oils, naphthenic oils, synthetic liquid oligomers of polyolefins (e.g., polybutylene and polypropylene), hydrocarbon fluids, vegetable oils, and combinations thereof. In some embodiments, suitable plasticizers may have a number average molecular weight (Mn) of from about 1,000, about 2,000 to about 6,000, or about 10,000, or a molecular weight between any pair of the foregoing values.

In some embodiments, the plasticizer may be hydroxyl modified (-OH modified) or may be unmodified. In some embodiments, the hot melt pressure sensitive adhesive composition comprises a first plasticizer modified with hydroxyl groups and a second plasticizer that is not modified with hydroxyl groups. Suitable hydroxyl modifying plasticizers include those containing from about 0.5 weight percent, about 1 weight percent, or about 2 weight percent to about 7 weight percent, about 8 weight percent, or about 9 weight percent-OH, or a weight percent of-OH between any pair of the foregoing values, based on the total weight of the plasticizer. In some embodiments, the plasticizer may be a hydroxylated compound reactive with the isocyanate compound.

In some embodiments, the plasticizer may be a liquid resin that may or may not be hydroxyl modified. In some embodiments, the plasticizer may be a hydroxylated compound, such as a hydroxyl terminated polybutene, a hydroxyl modified liquid resin, or a combination thereof.

In some embodiments, a suitable plasticizer may be a liquid polybutene, which is-OH modified or unmodified, and is liquid at room temperature. Suitable plasticizers include liquid polybutenes having a viscosity of from about 500 centipoise (cp), about 2,000cp, or about 6,000cp to about 10,000cp, about 50,000cp, or about 70,000cp, or a viscosity between any pair of the foregoing values, at a temperature of about 25 to about 35 ℃.

Suitable commercially available plasticizers may include those available under the trade name

Those sold in series (available from Nynas Corp, located in Houston, TX), including, for example, NYFLEX 222B; oils, e.g. under the trade name

Those sold (available from Sonneborn, LLC, located in Parsippany, NJ); mineral oils, e.g. under the trade name KRYSTOL^TMThose sold, for example, KRYSTOL550 (available from Petrochem Carless Ltd, Surrey, uk); oils such as those sold under the trade name CALSOL 550 (available from Calumet Specialty Products Partners, LP, located IN Indianapolis, IN); rubber oils such as those sold under the product name KN401 (available from Fuda Petrochemical co., Ltd, hang, china); and polyalphaolefins, e.g. under the trade name SPECTRASYN^TMThose sold in series (available from ExxonMobil Chemical Co located in Houston, TX) include, for example, SPECTRASYN 4 and 40.

Suitable plasticizers may include certain commercially available liquid hydrocarbon resins, such as those under the trade name REGALITE^TMThose sold under the name ESCOREZ (available from Eastman Chemical Co., located in Kingsport, TN) by C8010^TMSome examples of those sold, for example ESCOREZ 5040 (available from ExxonMobil Chemical Co, located in Houston, TX). Other suitable-OH modified liquid resins that may be used as plasticizers include those known under the trade name

Those sold (obtained from Germany)

Germany GmbH), including for example

Those in the series, such as the LA, LC, HA, TNA, CA or LS series.

Suitable plasticizers may include

Liquid polybutenes (available from Cray Valley of Exton, PA) sold under the trade name series, for example

130. 142 or 150. Suitable polybutenes may be available under the trade name

Those sold in series (INEOS from london, uk). Other suitable plasticizers include

liquid-OH-modified polybutenes (Cray Valley from Exton, Pa.) sold in series, for example

LBH-2000, 3000 or 5000.

The plasticizer is present in the hot melt pressure sensitive adhesive composition in an amount of from 1 wt%, about 5 wt%, about 10 wt%, or about 15 wt% to about 30 wt%, about 40 wt%, or about 50 wt%, based on the total weight of the adhesive composition, or in an amount between any pair of the foregoing values, although other values are contemplated. In embodiments having more than one plasticizer, the total amount of plasticizer or plasticizers present in the hot melt pressure sensitive adhesive can be from about 1 weight percent, about 5 weight percent, about 10 weight percent, or about 15 weight percent to about 30 weight percent, about 40 weight percent, or about 50 weight percent (based on the total weight of the adhesive composition), or an amount between any pair of the foregoing values, although other values are contemplated.

Other Components

In some embodiments, the hot melt pressure sensitive adhesive composition optionally includes one or more of a variety of other components including, for example, stabilizers, antioxidants, adhesion promoters, ultraviolet light stabilizers, rheology modifiers, biocides, corrosion inhibitors, dehydrating agents, colorants (e.g., pigments and dyes), fillers, surfactants, flame retardants, waxes, other polymers, and mixtures and combinations thereof.

In some embodiments, the hot melt pressure sensitive adhesive composition comprises one or more antioxidants. In some embodiments, suitable antioxidants include, but are not limited to, pentaerythritol tetrakis [3, (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate]2,2' -methylenebis (4-methyl-6-tert-butylphenol), phosphites including, for example, tris (p-nonylphenyl) phosphite (TNPP) and bis (2, 4-di-tert-butylphenyl) 4,4' -diphenylenediphosphonite, distearyl-3, 3' -thiodipropionate (DSTDP), and combinations thereof. Useful antioxidants are commercially available under various trade names, including, for example, under the trade name

Hindered phenolic antioxidants sold in series (available from BASF Corporation, Florham Park, NJ) including, for example, IRGANOX 1010, IRGANOX 565, IRGANOX 1076; under the trade name of

Phosphite antioxidants sold, for example

168 (BASF available from Ludwigshafen, Germany) and 4,4' -methylenebis (2, 6-di-tert-butylphenol) available under the generic name Ethyl 702.

In some embodiments, the hot melt pressure sensitive adhesive composition comprises one or more catalysts. In some embodiments, a suitable catalyst may be selected to improve the reaction, formation and/or curing of the remaining components of the hot melt pressure sensitive adhesive composition. For example, the adhesive composition may include a curing catalyst, such as a polyurethane curing catalyst. Suitable curing catalysts that may be used to form the hot melt pressure sensitive adhesive composition include 2,2' -dimorpholinodiethyl ether (DMDEE), such as that available under the trade name DMDEE

Those sold (obtained from Hunstman Performance Products located in The Woodland, TX).

Method of forming hot melt pressure sensitive adhesive

In some embodiments, a method of forming the hot melt pressure sensitive adhesive composition includes combining the thermoplastic polymer, plasticizer, tackifier, and isocyanate compound to form the hot melt pressure sensitive adhesive composition.

In some embodiments, a method of forming the hot melt pressure sensitive adhesive composition includes combining the thermoplastic polymer, plasticizer, tackifier, and then adding an isocyanate compound to form the hot melt pressure sensitive adhesive composition. For example, a method of forming the hot melt pressure sensitive adhesive composition may include combining the thermoplastic polymer with a tackifier and a plasticizer in a first step, followed by a second step of adding an isocyanate compound. In some embodiments, in a second step, a catalyst is added to the thermoplastic polymer, plasticizer, hydroxyl-containing tackifier, and isocyanate compound to aid in forming the hot melt pressure sensitive adhesive composition.

In some embodiments, in a first step, the thermoplastic polymer, plasticizer, and tackifier are maintained at a first temperature while the components are combined. In some embodiments, in the second step, the isocyanate compound is added to the components combined in the first step and the components combined in the second step are maintained at a second temperature that may be higher, lower, or equal to the first temperature. In a preferred embodiment, the second temperature is lower than the first temperature. For example, the first temperature may be from about 100 ℃, about 120 ℃, or about 140 ℃ to about 160 ℃, about 180 ℃, or about 200 ℃, or a temperature between any pair of the foregoing values, although other temperatures are further contemplated. In some embodiments, the second temperature may be a temperature from about 70 ℃, about 80 ℃, about 90 ℃, or about 100 ℃ to about 120 ℃, about 130 ℃, or about 140 ℃, or between any pair of the foregoing values, although other temperatures are further contemplated.

The components of the hot melt pressure sensitive adhesive composition can be combined in a pressure controlled container, for example, a container that can maintain the pressure inside the container above, at, or below the pressure outside the container, e.g., atmospheric pressure. As an example, the components of the hot melt pressure sensitive adhesive composition may be combined in a container, and in the first step and/or the second step, the interior of the container may be maintained at a pressure below atmospheric pressure. In some embodiments, the first step comprises combining the thermoplastic polymer, plasticizer, tackifier in the container for a time of about 1 hour, about 2 hours to about 3 hours, about 4 hours, or about 5 hours, or between any pair of the foregoing values, while maintaining the pressure inside the container at a pressure below atmospheric pressure. In some embodiments, the second step comprises combining the components combined in the first step with the isocyanate compound and optional catalyst in a vessel for a period of about 0.5 hours, about 1 hour to about 2 hours, about 3 hours, or about 4 hours, or between any pair of the foregoing values, while maintaining the pressure inside the vessel at a pressure below atmospheric pressure. In some embodiments, the first step and/or the second step may comprise maintaining a pressure within the vessel of about-0.5 MPa, about-1.0 MPa, about-1.5 MPa, or about-2.0 MPa relative to atmospheric pressure.

Sample procedure for forming hot melt pressure sensitive adhesive

In some embodiments, a method for forming a hot melt pressure sensitive adhesive composition comprises: in a first step, a thermoplastic polymer is added to a container in an amount of from about 5 to about 70 weight percent, a tackifier in an amount of from greater than 0.0 to about 80 weight percent, and a plasticizer in an amount of from about 15 to about 25 weight percent, all based on the total final weight of the hot melt pressure sensitive adhesive composition. The components combined in the first step may be mixed in the vessel for about 2-3 hours. The pressure inside the container can be maintained at about-1.0 MPa relative to atmospheric pressure. During the first step, the components of the vessel may be maintained at a temperature of from about 100 to about 200 ℃.

In some embodiments, in a second step, an isocyanate compound in an amount of from about 1 to about 20 weight percent and a catalyst in an amount of about 0.2 weight percent (all based on the total final weight of the hot melt pressure sensitive adhesive composition) are added to the components combined in the first step. In some examples, the total weight percent of the thermoplastic polymer, tackifier, plasticizer, isocyanate compound, and catalyst comprises at least 90 weight percent of the final weight of the hot melt pressure sensitive adhesive composition. In some examples, the total weight percent of the thermoplastic polymer, tackifier, plasticizer, isocyanate compound, and catalyst comprises at least 95 weight percent of the final weight of the hot melt pressure sensitive adhesive composition. The components combined in the second step may be mixed in a container for about 0.5 to about 2 hours to form the hot melt pressure sensitive adhesive composition. The pressure inside the container can be maintained at about-1.0 MPa relative to atmospheric pressure. During the second step, the components of the vessel may be maintained at a temperature of from about 80 to about 130 ℃.

In a preferred embodiment, a method of forming a hot melt pressure sensitive adhesive composition comprises adding to a container in a first step a thermoplastic polymer in an amount of from about 15 to about 40 weight percent, a tackifier in an amount of from about 10 to about 40 weight percent, and a plasticizer in an amount of from about 20 to about 25 weight percent, all based on the total final weight of the hot melt pressure sensitive adhesive composition. The components combined in the first step may be mixed in the vessel for about 2-3 hours. The pressure inside the container can be maintained at about-1.0 MPa relative to atmospheric pressure. During the first step, the components of the vessel may be maintained at a temperature of from about 100 to about 200 ℃.

In some embodiments, in a second step, an isocyanate compound in an amount of from about 5 to about 10 weight percent and a polyurethane curing catalyst in an amount of about 0.2 weight percent (all based on the final total weight of the hot melt pressure sensitive adhesive composition) are added to the components combined in the first step. In some examples, the total weight percent of the thermoplastic polymer, tackifier, plasticizer, isocyanate compound, and catalyst comprises at least 90 weight percent of the final weight of the hot melt pressure sensitive adhesive composition. In some examples, the total weight percent of the thermoplastic polymer, tackifier, plasticizer, isocyanate compound, and catalyst comprises at least 95 weight percent of the final weight of the hot melt pressure sensitive adhesive composition. The components combined in the second step may be mixed in a container for about 0.5 to about 2 hours to form the hot melt pressure sensitive adhesive composition. The pressure inside the container can be maintained at about-1.0 MPa relative to atmospheric pressure. During the second step, the components of the vessel may be maintained at a temperature of from about 80 to about 130 ℃.

Typically, the use of block copolymers comprising low glass transition temperature (Tg) segments as the polymer backbone in hot melt adhesives can provide useful levels of tack (tack) and adhesion (adhesion). In some cases, cohesion (cohesion) and high temperature performance under certain conditions may be limited due to the low molecular weight of certain materials (e.g., certain oils or tackifiers) in the hot melt adhesive. In some cases, it may also be difficult to prepare hot melt adhesives that contain isocyanate-terminated chemicals that are compatible with polyolefins or rubbers or similar components when forming hot melt pressure sensitive adhesives. It has been found that in some cases, a certain degree of crosslinking between the hot melt pressure sensitive adhesive components can help to increase the cohesive strength of the adhesive composition and increase the range of substrates to which the adhesive can adhere. In some cases, adjusting the percentage of thermoplastic polymer content in the hot melt pressure sensitive adhesive composition can help to further adjust the level of cohesion and the materials to which the hot melt adhesive can adhere.

Additionally or alternatively, a hot melt adhesive composition having certain pressure sensitive properties may be formed. For example, it has been found that the addition of hydroxyl containing compounds to hot melt adhesives can be used to help increase the pressure sensitive properties of the hot melt adhesive composition. Some other techniques include the addition of certain plasticizers and/or tackifiers that help to increase pressure-sensitive properties without compromising other desired properties. In some cases, the method used to form the hot melt pressure sensitive adhesive may be selected so as to help impart the desired cohesive properties to the adhesive. For example, the thermoplastic polymer, tackifier and plasticizer are first mixed, and then an isocyanate compound such as MDI is added, which can prepare a pressure-sensitive hot melt adhesive that can be cured by reaction with moisture in the air.

It has been found in some instances that it may be preferable to form the hot melt pressure sensitive adhesive composition by selecting the components of the hot melt pressure sensitive adhesive composition such that the adhesive composition exhibits crosslinking between the adhesive composition components after the adhesive composition has cured. For example, it has been found that certain types of tackifiers (e.g., those having hydroxyl groups) can be advantageous. As an example, a tackifier (e.g., a resin having hydroxyl groups) may be polymerized with an isocyanate compound (e.g., MDI) to form a hot melt pressure sensitive adhesive composition. When the hot melt pressure sensitive adhesive composition is exposed to air, it can be cured by moisture (e.g., by ambient moisture in the air), thereby forming a cured adhesive having a degree of crosslinking. In some examples, the addition of a plasticizer that is reactive with other components of the adhesive composition can aid in crosslinking of the adhesive composition components and can aid in increasing cohesion. For example, the addition of a hydroxyl-containing plasticizer can increase the cohesion of the cured adhesive composition.

It has been found that the hot melt pressure sensitive adhesive compositions disclosed herein have good stability, e.g., viscosity stability and viscosity growth rate stability, up to high temperatures, e.g., about 150 ℃. The good viscosity stability makes the hot melt pressure sensitive adhesive compositions disclosed herein useful in a wide range of applications. It has been found that in some compositions, controlling a certain level of MDI can adjust viscosity stability, which can adjust the adhesive composition to accommodate various manufacturing processes. For example, the hot melt pressure sensitive adhesive composition can maintain viscosity stability at temperatures used for melting and allow the adhesive composition to be applied as a liquid under manufacturing conditions.

The hot melt pressure sensitive adhesive compositions disclosed herein have been found to be suitable for bonding a wide range of substrates formed from a variety of materials such as PC, PE, PET, PVC, PP, ABS, PA, and the like. It has been found that the hot melt pressure sensitive adhesive compositions disclosed herein have good tack, good cohesive strength, good peel strength and good holding power. The hot melt pressure sensitive adhesive compositions disclosed herein maintain these characteristics at elevated temperatures, for example, at room temperature to temperatures, for example, up to 100 ℃.

It has been found that the hot melt pressure sensitive adhesive compositions disclosed herein also exhibit pressure sensitive characteristics after the adhesive composition is cured. The adhesive composition may be tacky at room temperature (e.g., 25-35 ℃) and at temperatures above room temperature (e.g., room temperature to 100 ℃). The adhesive composition is flexible even after curing.

In some examples, the hot melt pressure sensitive adhesive composition disclosed herein can be applied as a liquid to a first substrate. The viscosity stability allows the adhesive composition to remain liquid when the adhesive composition is transported and applied to a first substrate (e.g., when the adhesive composition is transported through a tube and/or nozzle at an elevated temperature). In some applications, the second substrate may be attached to the first substrate by contacting the second substrate with the adhesive composition that has been applied to the first substrate. For example, the second substrate may be contacted with the first substrate before or after the adhesive composition is cured. The pressure sensitive properties may aid in positioning the second substrate relative to the first substrate when the adhesive composition is cured, and/or after it is cured. The characteristics and properties of the hot melt pressure sensitive adhesive composition, including but not limited to those described herein, provide the user with a wide range of applications and a range of conditions to which the adhesive composition can be applied.

In some examples, the adhesive composition may be applied to a first substrate, for example, as a film, and then the first substrate is attached to a second substrate after the adhesive composition is cured. In certain instances, the adhesive composition can be used to form a tape, such as a removable tape. The adhesive composition can be used to make tapes with high temperature properties because the adhesive composition can remain tacky at elevated temperatures (e.g., above room temperature). In some cases, crosslinking of the adhesive composition components helps to improve and maintain the cohesive strength of the adhesive composition even at elevated temperatures. For example, a tape formed using the hot melt adhesive composition disclosed herein can be applied to a substrate at about room temperature and maintain its tack level when the tape is heated to a temperature above room temperature.

The hot melt pressure sensitive adhesive compositions disclosed herein can be used in the manufacture of articles and/or for bonding to substrates made from a wide range of materials including, but not limited to, wood, cardboard, paper, metal, plastic, rubber, glass, nonwoven, and textiles. Other examples include consumer products and specialized industrial applications. Markets in which the hot melt pressure sensitive adhesive compositions may be used include disposable articles such as diapers or feminine hygiene products, textiles such as carpets and garments, food packaging, footwear, consumer electronics, construction, furniture, automobiles and aircraft. Various applications include, but are not limited to, use in marine and automotive applications, windows, for making doors (including entry doors, garage doors, etc.), for making building panels, for bonding parts outside of vehicles such as headlamps, etc.

The hot melt pressure sensitive adhesive compositions disclosed herein can be used to bond articles together by: the adhesive composition is applied to a surface of a first article in liquid or molten form, a second article is contacted with the adhesive composition applied to the first article, and the applied adhesive composition is under conditions that allow the adhesive composition to cool and solidify into a solid form. In some cases, the conditions used to cool and cure the adhesive composition may include an environment containing ambient moisture that can react with the components of the adhesive composition to cure the adhesive.

The adhesive composition may be dispensed and stored in solid form and stored in the absence of moisture. When the adhesive composition is ready for use, the solid adhesive composition may be heated and melted prior to application.

Examples

The following non-limiting examples are included to further illustrate various embodiments of the present disclosure and are not intended to limit the scope of the present disclosure.

Test method

Viscosity test method

The viscosity was determined on the composition to be tested heated to 150 ℃ using a Brookfield DV2T viscometer and a spindle 27 rotating at 5-10 rpm.

Viscosity stability is determined by measuring viscosity on an hourly basis according to the viscosity test method of ASTM D445(ISO3104) and calculating the increase as a percentage of the initial viscosity. The samples were aged in the viscometer.

Viscosity test method

Tack or tack testing can be performed by placing a sample of the adhesive composition on a first substrate and contacting a second substrate (e.g., a piece of paper, a piece of plastic, or a finger) with the sample of adhesive composition. Samples of the adhesive composition were formed into 0.15mm thick, 2.5cm (1 inch) wide films. The samples were applied at a temperature of 150 ℃. After one week of curing, the samples were measured at a temperature of 25 ℃. A non-increase in the amount of force required to remove the second substrate from the adhesive composition will indicate no tack or no tack. A low tack or low tack is found if the second substrate remains in place at a location along the first substrate where the second substrate is in contact with the adhesive composition, but can be separated from the first substrate with minimal force without deforming the adhesive composition sample. A medium tack or viscosity can be found if the second substrate is contacted with the adhesive composition and the surface shape of the adhesive composition changes as the second substrate separates from the first substrate. Moderate tack can be found in materials such as gums or sap. High tack or stickiness is found when separation of the second substrate from the portion of the first substrate having the adhesive composition results in a change in the shape of a sample of the adhesive composition or the shape of the first or second substrate, including but not requiring damage to the first and/or second substrate, such as difficulty in removing plywood or plastic, tearing the cardboard or paper surface, the adhesive composition remaining on the skin of a finger when the finger is removed from the adhesive composition. High tack is generally comparable to household tape such as packaging tape or duct tape.

Shear and peel test method

The shear test was performed by laminating a first 3mm thick Polycarbonate (PC) substrate with the adhesive composition to form a film of the adhesive composition having a thickness of 0.15 mm. The applied adhesive composition was then contacted with a second 3mm thick Polycarbonate (PC) substrate after laminating the adhesive composition to the PC substrate for about 5-20 minutes. Shear testing was performed after sample preparation and then held for one week in a constant temperature and humidity chamber set at 25 ℃ and 50% relative humidity.

Using a vacuum having 1/2 inches²(3.23cm²) Test samples for shear testing were cut from standard Polycarbonate (PC) lap shear panels of lap area and 0.005 inch (0.0127cm) spacing, with each sample having dimensions of 1 inch (2.54 cm) by 4 inches (10.16 cm) and 3mm thickness.

Test samples for peel samples were cut using a standard Polycarbonate (PC) lap shear plate (lap-shear), each sample having dimensions of 1 inch (2.54 cm) by 4 inches (10.16 cm) and 3mm thickness. The sample for the peel test was formed by laminating a 3mm thick Polycarbonate (PC) substrate with an adhesive composition to form an adhesive composition film having a thickness of 0.15 mm. Then, after laminating the adhesive composition to a PC substrate for about 5 to 20 minutes, the applied adhesive composition was contacted with a 0.05mm thick polyethylene terephthalate (PET) film. The peel test was performed after sample preparation and then held in a constant temperature and humidity chamber set at 25 ℃ and 50% relative humidity for one week.

The traveling speed of the shear and peel tester was 50 mm/min. All data are used under the trade name 25 ℃ and 60% humidity

The obtained test machine (model LEGEND 2369, obtained from Illinois Tool Inc. located in Norwood, MA) was measured.

Holding power test method

Using a vacuum having 1/2 inches²(3.23cm²) Test samples for retention testing were cut from standard Polycarbonate (PC) lap shear panels of lap area and 0.005 inch (0.0127cm) spacing, with each sample having dimensions of 1 inch (2.54 cm) by 4 inches (10.16 cm) and 3mm thickness.

The holding power test was conducted by laminating a first 3mm thick PC substrate with the adhesive composition to form an adhesive composition film having a thickness of 0.15 mm. The applied adhesive composition was then contacted with a second 3mm thick PC substrate within 5-20 minutes of lamination to the PC substrate.

The retention test was performed after one week after the sample was formed and then held in a constant temperature and humidity chamber set at 25 ℃ and 50% relative humidity for one week.

For the test samples, each sample was suspended vertically in an oven. The top surface of each sample was fixed and the bottom surface was loaded with 1kg weight. The test sample was placed in an oven for about 1 (one) hour to bring the adhesive composition to the test temperature. The time at which the loaded sample sags (drop) after heating to the test temperature was recorded.

Example 1

In a first exemplary sample, a SIS block copolymer (SIS 1105, Grand Petrochemical co., Ltd., available from ningbo, china), a first tackifier (SYLVARES) were combined in a first step^TMTP 300, terpene phenolic resin available from KRATON Corp., Houston, TX), second tackifier (LUHOREZ)^TMM90, Luhua Hongjin New Material Co, from china catabo) and a plasticizer in the form of a naphthenic oil (KN4010, from Fuda Petrochemical Co, Ltd, hang, china) were combined in a container. The components of the container combined in the first step are maintained at a temperature of about 100 to about 200 ℃ while the components are combined. While the components are mixed in the container, a vacuum is drawn inside the container and the pressure inside the container is maintained at less than or equal to-0.9 MPa relative to atmospheric pressure for about 2-3 hours. At the end of the first step, the components combined in the first step are cooled to a temperature of about 80 to about 130 ℃.

After the first step, MDI (B) is reacted in a second step

44C Fused, obtained from Covestro of Leverkusen, Germany) and catalyst 2,2' -dimorpholinodiethylether (

DMDEE, huntman available from The Woodlands, TX) was added to The components combined in The container in The first step. During the second step, the contents of the vessel in the second step are maintained at a temperature of from about 80 ℃ to about 130 ℃. While the components are mixed, a vacuum is drawn inside the container and the pressure inside the container is maintained at less than or equal to-0.9 MPa relative to atmospheric pressure for about 0.5 to about 2 hours. At the end of the second step, a hot melt pressure sensitive adhesive is prepared. Table 1 shows the weight of the components of the first exemplary sample, sample a2 (in grams, listed in table 1) and various test parameters.

A first comparative sample was prepared for comparison with sample a 2. The components used to form the first comparative example are shown in table 1 and the sample is entitled sample a 1. Sample a1 was typically prepared using the same procedure as used to prepare sample a 2. However, MDI was not added in step 2 to form sample a 1.

Example 2

In a second exemplary embodiment, sample B2 was prepared using the same procedure as the hot melt pressure sensitive adhesive used to form sample a 2. However, in sample B2, the SIS block copolymer was replaced with an SIS copolymer obtained under the product name SIS 1126 (Grand Petrochemical co., Ltd., nibo, china), and the first tackifying resin was replaced with a one obtained under the trade name SYLVARES^TMTP 96 obtained resin (available from KRATON, corp., Houston, TX) was substituted. The amounts of the components in sample B2 are shown in table 1 along with various test parameters.

A second comparative sample was prepared for comparison with sample B2. The first comparative example is included in table 1, entitled sample B1. Sample B1 was prepared using the same procedure as used to prepare sample B2. However, MDI was not added to form sample B1. The amounts of the components used to prepare sample B1 are included in table 1.

Example 3

In a third exemplary embodiment, sample C2 was prepared using the same procedure as the hot melt pressure sensitive adhesive used to form samples a2 and B2. However, in sample C2, the SIS block copolymer was replaced with an SIS copolymer obtained under the product name D1124 (available from KRATON, Corp., Houston, TX), and the first tackifying resin was replaced with a SYLVARES (R) resin under the product name SYLVARES^TMTP 105 resin (available from KRATON, corp., Houston, TX) was substituted.The amounts of components in sample C2 are shown in table 1 along with various test parameters.

A third comparative sample was prepared for comparison with sample C2. A third comparative example is included in table 1, entitled sample C1. Sample C1 was prepared using the same procedure as used to prepare sample C2. However, MDI was not added to form sample C1. The amounts of the components used to prepare sample C1 are included in table 1.

As shown in table 1, comparing sample a2 to sample a1, comparing sample B2 to B1, and comparing sample C2 to C1, the addition of MDI increased the peel strength above that of the corresponding control sample without MDI. As shown, in sample a2, the peel strength was more than 6 times higher than sample a1 without MDI. The increase in shear strength in the exemplary examples is also shown above the corresponding comparative sample without MDI. In some examples (e.g., sample B2 and sample C2), the addition of MDI resulted in about a four-fold increase in shear strength over the corresponding control sample without MDI.

Fig. 1 is a graph showing the holding times at various temperatures for the samples contained in table 1. As shown in fig. 1 and as indicated in table 1, the retention time 2 for sample a1, the retention time 4 for sample B1, and the retention time 6 for sample C1 were all less than 1 minute at 40 ℃. As shown in fig. 1 and table 1, sample a2 was first exposed to a temperature of about 40 ℃ for about 1 hour. After about 1 hour at 40 ℃, sample a2 did not fail and the temperature was then raised to 60 ℃. After this thermal history, the retention time 10 for sample a2 was then about 40 minutes at a temperature of about 60 ℃. As shown in fig. 1 and table 1, sample C2 was first exposed to a temperature of about 40 ℃ for about 1 hour. After about 1 hour, the temperature was raised to 60 ℃. After about 18 hours at 60 ℃, sample C2 did not fail and was then exposed to a higher temperature of 75 ℃. After the previous thermal history, the retention time 12 for sample C2 was about 4 hours 10 minutes at 75 ℃. As shown in fig. 1 and table 1, sample B2 was exposed to a temperature of about 40 ℃ for about 1 hour, then to a temperature of about 60 ℃ for about 18 hours, then to a temperature of about 75 ℃ for about 30 hours, then to a temperature of about 85 ℃ for about 70 hours, and then to a temperature of 100 ℃, and the bond did not fail. That is, sample B2 was exposed to a continuously elevated temperature of 40 ℃, then 60 ℃, then 75 ℃, then 85 ℃ and 100 ℃. The adhesion of sample B2 did not fail after the total hold time 14 of sample B2 exceeded 145 hours.

As shown in table 1, by adjusting the amount of thermoplastic polymer used to form the hot melt pressure sensitive adhesive composition, the tack or tack level of the adhesive composition before and after curing can be adjusted. It has been observed that high tack can be obtained when the amount of thermoplastic polymer used is relatively low, for example at about 17% or 18% by weight. When the thermoplastic polymer (e.g., styrenic block copolymer) content in the hot melt pressure sensitive adhesive composition is relatively high (e.g., about 42 wt%), the tack level may be relatively low. For example, comparing samples a2 and C2, where C2 has twice as much thermoplastic polymer content, in some cases the tack level in the adhesive composition is lower than with an adhesive composition with a higher thermoplastic polymer. As shown in sample C2, in adhesive compositions with higher thermoplastic polymers, the level of tack of the adhesive composition after curing may be lower than its level before curing.

As also shown in table 1, cohesive strength can be about 3 times higher by adjusting the amount of MDI in the adhesive composition. For example, reading the shear strength and peel strength shown in Table 1, the effect of MDI on these properties is shown by comparing samples A2, B2, and C2. It is generally believed that the larger amount of MDI provides a higher level of crosslinking, thereby strengthening the polymer network throughout the adhesive composition and helping to adjust shear and peel strength. Furthermore, the viscosity level after curing and the holding time at elevated temperature can also be adjusted to the desired values by finding a suitable amount of MDI.

Various modifications and additions may be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, although the above examples refer to particular features, the scope of the present invention also includes embodiments having different combinations of features and embodiments that do not include all of the above features.

Claims

1. A hot melt pressure sensitive adhesive composition comprising, based on the total weight of the adhesive composition:

from 1 to 20% by weight of an isocyanate group-terminated compound;

from 1 to 50 wt% of a plasticizer;

from 5 to 70 weight percent of a thermoplastic polymer; and

from 1 to 60% by weight of a tackifier,

wherein at least one of the plasticizer or tackifier contains isocyanate-reactive groups,

wherein the combined weight percent of the isocyanate-terminated compound, plasticizer, thermoplastic polymer, and tackifier is at least 90 percent, based on the total weight of the adhesive composition.

2. The hot melt pressure sensitive adhesive composition of claim 1, further comprising a polyurethane curing catalyst.

3. The hot melt pressure sensitive adhesive composition of claim 1 or 2, wherein the combined weight percent of the isocyanate-terminated compound, plasticizer, thermoplastic polymer, and tackifier is at least 95 percent, based on the total weight of the adhesive composition.

4. The hot melt pressure sensitive adhesive composition of claim 1 or 2, wherein the hot melt pressure sensitive adhesive composition contains a first plasticizer that does not contain a hydroxyl group and is at least one of an oil, a liquid resin, or a liquid polymer, and a second plasticizer that contains a hydroxyl group.

5. The hot melt pressure sensitive adhesive composition of claim 3, wherein the hot melt pressure sensitive adhesive composition contains a first plasticizer that does not contain hydroxyl groups and is at least one of an oil, a liquid resin, or a liquid polymer, and a second plasticizer that contains hydroxyl groups.

6. The hot melt pressure sensitive adhesive composition of any one of claims 1, 2, 5, wherein the plasticizer and tackifier each contain hydroxyl groups.

7. The hot melt pressure sensitive adhesive composition of claim 3, wherein the plasticizer and tackifier both contain hydroxyl groups.

8. The hot melt pressure sensitive adhesive composition of claim 4, wherein the plasticizer and tackifier both contain hydroxyl groups.

9. The hot melt pressure sensitive adhesive composition of any one of claims 1, 2, 5, 7-8, wherein the tackifier is at least one of an aliphatic resin, an aromatic modified resin, a cycloaliphatic resin, a hydroxyl modified resin, or a hydrogenated version thereof.

10. The hot melt pressure sensitive adhesive composition of claim 6, wherein the tackifier is at least one of an aliphatic resin, an aromatic modified resin, a cycloaliphatic resin, a hydroxyl modified resin, or a hydrogenated version thereof.

11. The hot melt pressure sensitive adhesive composition of any one of claims 1, 2, 5, 7-8, 10, wherein the thermoplastic polymer is at least one of a propylene-rich polyolefin, a butene-rich polyolefin, or an ethylene-rich polyolefin.

12. The hot melt pressure sensitive adhesive composition of claim 9, wherein the thermoplastic polymer is at least one of a propylene-rich polyolefin, a butene-rich polyolefin, or an ethylene-rich polyolefin.

13. The hot melt pressure sensitive adhesive composition of any one of claims 1, 2, 5, 7-8, 10, wherein the thermoplastic polymer is a styrenic block copolymer.

14. The hot melt pressure sensitive adhesive composition of claim 9, wherein the thermoplastic polymer is a styrenic block copolymer.

15. The hot melt pressure sensitive adhesive composition of any one of claims 1, 2, 5, 7-8, 10, 12, 14, wherein the isocyanate group-terminated compound is a monomeric diisocyanate.

16. The hot melt pressure sensitive adhesive composition of claim 11, wherein the isocyanate group-terminated compound is a monomeric diisocyanate.

17. The hot melt pressure sensitive adhesive composition of claim 13, wherein the isocyanate group-terminated compound is a monomeric diisocyanate.

18. The hot melt pressure sensitive adhesive composition of any one of claims 1, 2, 5, 7-8, 10, 12, 14, wherein the isocyanate-terminated compound is at least one of methylene diphenyl diisocyanate, hydrogenated methylene diphenyl isocyanate, hexamethylene diisocyanate, isophorone diisocyanate, polymeric methylene diphenyl diisocyanate, toluene diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate, or polymethylene polyphenyl isocyanate.

19. The hot melt pressure sensitive adhesive composition of claim 11, wherein the isocyanate-terminated compound is at least one of methylene diphenyl diisocyanate, hydrogenated methylene diphenyl isocyanate, hexamethylene diisocyanate, isophorone diisocyanate, polymeric methylene diphenyl diisocyanate, toluene diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate, or polymethylene polyphenyl isocyanate.

20. The hot melt pressure sensitive adhesive composition of claim 13, wherein the isocyanate-terminated compound is at least one of methylene diphenyl diisocyanate, hydrogenated methylene diphenyl isocyanate, hexamethylene diisocyanate, isophorone diisocyanate, polymeric methylene diphenyl diisocyanate, toluene diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate, or polymethylene polyphenyl isocyanate.

21. The hot melt pressure sensitive adhesive composition of any one of claims 1, 2, 5, 7-8, 10, 12, 14, 16-17, 19-20, comprising an isocyanate group-terminated compound in an amount of 5-20 wt.%, a thermoplastic polymer in an amount of 15-40 wt.%, a tackifier in an amount of 10-50 wt.%, a plasticizer in an amount of 15-30 wt.%, and a polyurethane curing catalyst in an amount of 0.2 wt.%, all based on the total weight of the hot melt pressure sensitive adhesive composition.

22. The hot melt pressure sensitive adhesive composition of claim 18, comprising an isocyanate group-terminated compound in an amount of 5 to 20 weight percent, a thermoplastic polymer in an amount of 15 to 40 weight percent, a tackifier in an amount of 10 to 50 weight percent, a plasticizer in an amount of 15 to 30 weight percent, and a polyurethane curing catalyst, all based on the total weight of the hot melt pressure sensitive adhesive composition.

23. A hot melt pressure sensitive adhesive composition comprising:

the reaction product of:

an isocyanate compound which is a mixture of at least one isocyanate compound,

a plasticizer, and

a tackifier; and

a thermoplastic polymer,

wherein at least one of the plasticizer or tackifier is hydroxyl terminated,

24. The hot melt pressure sensitive adhesive composition of claim 23, wherein the hot melt pressure sensitive adhesive composition is tacky at room temperature.

25. The hot melt pressure sensitive adhesive composition of claim 23 or 24, wherein the tackifier and plasticizer are both hydroxyl-modified, and wherein the hot melt pressure sensitive adhesive composition further comprises a second plasticizer that is not hydroxyl-modified.

26. The hot melt pressure sensitive adhesive composition of claim 23 or 24, wherein the hot melt pressure sensitive adhesive composition exhibits a viscosity increase of less than 1%/hour at a temperature of 150 ℃.

27. The hot melt pressure sensitive adhesive composition of claim 25, wherein the hot melt pressure sensitive adhesive composition exhibits a viscosity increase of less than 1%/hour at a temperature of 150 ℃.

28. The hot melt pressure sensitive adhesive composition of any one of claims 23, 24, 27, wherein the hot melt pressure sensitive adhesive composition has a 180 ° peel strength of at least 5N/cm after curing.

29. The hot melt pressure sensitive adhesive composition of claim 25, wherein the hot melt pressure sensitive adhesive composition has a 180 ° peel strength of at least 5N/cm after curing.

30. The hot melt pressure sensitive adhesive composition of claim 26, wherein the hot melt pressure sensitive adhesive composition has a 180 ° peel strength of at least 5N/cm after curing.

31. The hot melt pressure sensitive adhesive composition of any one of claims 23, 24, 27, 29-30, wherein the hot melt pressure sensitive adhesive composition has at least 23N/cm after curing²The shear strength of (2).

32. The hot melt pressure sensitive adhesive composition of claim 28, wherein the hot melt pressure sensitive adhesive composition has at least 23N/cm after curing²The shear strength of (2).

33. The hot melt pressure sensitive adhesive composition of any one of claims 23, 24, 27, 29-30, 32, wherein the hot melt pressure sensitive adhesive composition has a hold time at a temperature above 40 ℃ of greater than 1 minute for one week after curing.

34. The hot melt pressure sensitive adhesive composition of claim 31, wherein the hot melt pressure sensitive adhesive composition has a hold time at a temperature above 40 ℃ of greater than 1 minute for one week after curing.

35. The hot melt pressure sensitive adhesive composition of any one of claims 23, 24, 27, 29-30, 32, 34, wherein the hot melt pressure sensitive adhesive composition, upon curing, exhibits cross-linking between components of the hot melt pressure sensitive adhesive composition.

36. The hot melt pressure sensitive adhesive composition of claim 33, wherein the hot melt pressure sensitive adhesive composition exhibits cross-linking between components of the hot melt pressure sensitive adhesive composition upon curing.