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
  • C08L2666/14—Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof

Definitions

• the invention relates to the use of low molecular weight polyphenylene oxides in adhesive blends comprising styrenic triblock copolymers such as polystyrene-polyisoprene-polystyrene (S-I-S) and polystyrene-polybutadiene-polystyrene (S-B-S) to provide increases in the shear adhesion failure temperatures (SAFT) of the correspondi ng pressure sensi ti ve, hot mel t pressure sensi ti ve or hot mel t
• SAFT shear adhesion failure temperatures
• the SAFT increases are obtained without significant hot melt formulation viscosity increases and with little impact on the pressure sensitive adhesives' tack or peel strength.
• polyblends containing: (A) greater than 50% of a thermoplastic resin matrix, said resin matrix consisting of polyphenylene oxide resin in combination with alkenyl aromatic resins; and (B) less than 50% of an elastomer selected from a group consisting of poly(butadiene), and random, block or graft copolymers of butadiene and styrene.
• A greater than 50% of a thermoplastic resin matrix, said resin matrix consisting of polyphenylene oxide resin in combination with alkenyl aromatic resins
• an elastomer selected from a group consisting of poly(butadiene), and random, block or graft copolymers of butadiene and styrene.
• the materials in this patent are thermoplastic resins and not adhesives, and the degree of polymerization (DP) of polyphenylene oxide is greater than about 100.
• conjugated dienes and vinyl aromati c compounds conjugated dienes and vinyl aromati c compounds , and high impact rubber modified polystyrene compositions contai ning polyphenyl ene ether and vinyl aromatic block copolymers; however, the compositions are thermoplastics and the DP of the polyphenyl ene oxides is greater than 50.
• Hot melt adhesive compositions are disclosed in Hansen, U.S. Patent 4,104,323.
• the adhesive composition is prepared by first melt blending a polyphenylene ether resin and a low molecular weight aromatic resin, and then blending the resulting mixture and a monoalkenyl arene/conjugated diene block copolymer, tackifying resin, and optional hydrocarbon processing oil.
• the molecular weight of the polyphenylene oxide in the polyphenylene oxide alloy is between 6,000 and 25,000.
• the glass transition temperature is between 170 and 205oC. This melt blend avoids the use of solvents while also avoiding oxidative degradation of the block copolymer.
• the resulting polymer blend possesses a much higher service temperature when used as an adhesive.
• composition is prepared by melt blending a polyphenylene ether resin, a selectively hydrogenated arene/conjugated diene block copolymer, a tackifying resin, and optionally, a hydrocarbon processing oil.
• This patent is restricted to hydrogenated block copolymers which can withstand the extremely high blending temperatures required to disperse the polyphenylene oxide resins, (230oC to 260oC) and to polyphenylene oxide resins having a molecular weight (M vis ) between 6,000 and 25,000.
• M vis molecular weight
• the glass transition temperature of the resin is restricted to between 170° and 210oC.
• PPO low molecular weight polyphenylene oxide resins
• Illustrative of the blocks are styrenic block copolymers such as polystyrene-polybutadiene-polystyrene (S-B-S), polystyrene-polyisoprene-polystyrene (S-I-S), polystyrene-polyisoprene-polystyrene (S-I-S), polystyrene-polyisoprene-polystyrene (S-I-S), polystyrene-polyisoprene-polystyrene (S-I-S), polystyrene-polyisoprene-polystyrene (S-I-
• the tackifying resin which is compatible with the elastomeric midblock of the triblock copolymer, is used to render the formulation tacky.
• Preferred tackifying resins are those derived from the copolymerization of diolefins and especially of C 5
• diolefins such as piperylene with C 5 olefins such as
• 2-methyl-2-butene These resins, such as ESCOREZ 1310LC, available commercially from Exxon Chemical, have ring and ball softening points between 80°C to 115oC.
• Other useful tackifying resins include those derived from rosin esters, terpenes, and terpene phenolic resins. Hydrogenated versions of the above are also useful.
• Hydrocarbon extending oils (0-200 phr) can be employed in this application to modify the formulation viscosity and to increase the tackiness of the adhesive.
• the extending oils referred to as paraffinic/naphthenic oils are fractions of refined petroleum products having less than 30% by weight aromatics and viscosities ranging from 100 to 500 SSU at 100oF. Oils are commercially available such as Shellflex 371, a naphthenic oil manufactured by Shell.
• the adhesive formulations are prepared by dissolving in a solvent such as toluene, and casting over a substrate such as mylar.
• a solvent such as toluene
• the components are melt blended in a Brabender mixer.
• the temperature for melt blending will depend upon the T g of the PPO. This is a significant advantage of using PPO of lower T g than that claimed in U.S.
• polyphenylene oxide copolymers having low molecular weight and high glass transition temperatures, extend the temperature range of pressure sensitive and hot melt adhesive systems which contain styrenic triblock
• a pressure sensitive adhesive is a material which is aggressively and permanently tacky, adheres without the need of more than finger pressure, exerts a strong holding force, and has sufficient cohesiveness and elasticity that it can be removed from substrates without leaving a residue.
• a hot melt adhesive is a 100% nonvolatile thermoplastic material that is heated to a melt and applied to the substrate as a liquid. The hot melt bond forms after the liquid cools and solidifies.
• temperature range for these PPO resins ranges from 100-165oC, preferably between 140-163oC. This range, less than that described in U.S. Patents 4,104,323 and 4,141,876, provides superior adhesive service temperature increases while allowing hot melt processibility below 200°C.
• the upper use temperature of these adhesives is limited to the softening temperature (T g ) of the polystyrene domains.
• T g softening temperature
• a high T g PPO with good polystyrene thermodynamic compatibility increases the service temperature when blended into the adhesive formulation.
• Block copolymers employed in the invention may have geometrical structures, however the invention does not depend on a particular structure, but rather upon the chemical constitution of each of the polymer blocks.
• the structures may be linear, radial, or branched so long as each copolymer has at least two polymer endblocks and at least one polymer midblock.
• the invention contemplates (but is not limited to) the use of
• SBS polystyrene-polybutadiene-polystyrene
• Blocks A and B may be either homopolymer or random copolymer blocks as long as each block predominates in at least one class of the monomers characterizing the blocks as defined.
• blocks A may comprise styrene/alpha- methylstyrene copolymer blocks or styrene/butadiene random copolymer blocks as long as the blocks individually predominate in monoalkenyl arenes.
• monoalkenyl arene includes styrene and its analogs and homologs including alpha-methyl styrene and
• the blocks B may comprise homopolymers of butadiene, isoprene, copolymers of butadiene and isoprene and copolymers of one of these two dienes with monoalkenyl arene as long as the blocks B predominate in conjugated diene units.
• the rubbery midblock of these polymers may be hydrogenated, but non-hydrogenated midblocks can also be used since excessively high blending temperatures are not generally required to prepare the blends of the present inventory.
• the monomer employed is butadiene, it is preferred that between about 35 and about 55 mole percent of the condensed butadiene units in the butadiene polymer block, have a 1,2 configuration.
• Polyphenylene oxides of the invention will have repeating units represented by the formula:
• n is a positive integer of from 10 to about 40 thereby providing a MW range of about 1000-5000
• each Q is a monovalent substituent selected from the group consisting of hydrogen, halogen, hydrocarbon radicals, hydrocarbonoxy radicals, and halohydrocarbonoxy radicals having at least two carbon atoms between the halogen atom and phenyl nucleus.
• Especially preferred polyphenylene oxide resins for purposes of the present invention are those having alkyl substitutions in the two positions ortho to the oxygen ether atom - i.e. where each Q is alkyl, most preferably, having from 1 to 4 carbon atoms.
• the low molecular weight polyphenylene oxides are prepared using a cuprous chloride-pyridine catalyst system in chlorobenzene solution. Magnesium sulfate is used to remove moisture from the reactions. The products are isolated by precipitation with a 10% HCl/methanol solution, and are dissolved and reprecipitated to remove any residual traces of catalyst or diphenoquinone side products.
• PPO yields and glass transition temperatures are controlled by varying the degree of polymerization. This is achieved by changing the reaction time and consequently the amount of oxygen. A longer reaction time permits the formation of higher molecular weight and high T g products, which, when precipitated, afford higher recoveries.
• Polyphenylene oxides of low molecular weight, useful in the invention also can be prepared according to the Perec article in J. of Polymer Science (vol 25, p 2605) from 4 bromo-2,6-dimethylphenol as monomer (see Example 5).
• Cuprous chloride (10g) and pyridine (50ml) are stirred for 30 minutes in 500 ml chlorobenzene.
• o-Cresol (48ml) and anhydrous magnesium sulfate (1.5g) are added and the reaction is stirred for 28 hours at room temperature.
• the insoluble portion of the reaction is filtered away and the resin is precipitated with a 10% HCl/methanol solution.
• the resin is isolated by filtration and washed with methanol.
• the yield is 15g (301) of a pale orange, brittle solid.
• the glass transition temperature of the solid is 103oC and H-NMR of the solid shows a 1:1 ratio of aliphatic to aromatic protons.
• Cuprous chloride (10g) and pyridine (50ml) are stirred for 30 minutes at room temperature in 500 ml chlorobenzene.
• o-Cresol (25g), 2,6-xylenol (25g), and anhydrous magnesium sulfate (1.5g) are added and the reaction is stirred for 28 hours.
• the insoluble portion of the reaction mixture is removed by filtration and the resin is isolated by precipitation with 10% HCl/methanol.
• the resin is isolated by filtration and redissolved in toluene and precipitated with methanol to remove any residual catalyst or dimeric side products.
• the yield is 38g (761) of a pale orange solid.
• the glass transition temperature is 105oC and H-NMR analysis shows a 5:3 ratio of aliphatic to aromatic protons.
• Example 2 The procedure of Example 2 is followed except that 26.5g of 2,6-xylenol and 26.5 g of o-cresol are used. The reaction is stirred for 48 hours. A 70% yield of a pale orange solid is obtained. The glass transition temperature of the resin is 153oC and H-NMR analysis shows a 9:5 ratio of aliphatic to aromatic protons.
• Example 2 The procedure of Example 1 is followed except that 50g of 2,6-xylenol is used instead of the o-cresol. Also, the resin is dissolved in toluene and precipitated with methanol. A 61% yield of a yellow solid is obtained. The glass transition temperature of the solid is 154°C and H-NMR analysis of the solid shows a 3:1 ratio of aliphatic to aromatic protons.
• EXAMPLE 5 The procedure of Example 1 is followed except that 50g of 2,6-xylenol is used instead of the o-cresol. Also, the resin is dissolved in toluene and precipitated with methanol. A 61% yield of a yellow solid is obtained. The glass transition temperature of the solid is 154°C and H-NMR analysis of the solid shows a 3:1 ratio of aliphatic to aromatic protons.
• EXAMPLE 5 The procedure of Example 1 is followed except that 50g of 2,6-xylenol is used instead of the o-cresol. Also, the resin
• Example 3 The procedure of Example 3 was followed except that 75g 2, 6-xylenol, 50 mol pyridine, 900 ml chlorobenzene, and 5g magnesium sulfate were used. The mixture was stirred for 72 hours. The polymer yield was 43.5g, and the glass transition temperature was 145oC.
• the yields, glass transition temperatures, and product compositions for the PPO products prepared for testing in adhesive formulations are as follows:
• Example 6 145oC 30% 1 :1 Xylenol :o-Cresol PPO product compositions were determined using H-NMR spectroscopy. A ratio of aliphatic protons (1.5-2.5 ppm) to aromatic protons (6-7.4 ppm) indicates the relative amounts of cresol and xylenol present in the resins. An entirely 2,6-xylenol product contains a 3:1 ratio of aliphatic to aromatic protons while an entirely o-cresol product contains a 1:1 ratio of aliphatic to aromatic protons. In the following embodiments, examples and comparisons, these materials were employed:
• Shellflex 371 a naphthenic extending oil from Shell.
• Noryl a PPO from General Electric having a Tg of 194oC.
• S-I-S formulations with E-1310LC as tackifier resin were prepared for testing as pressure sensitive adhesives. All PPO products were used at two different levels and the 90° quick stick, 180° peel, polyken tack, and shear adhesion failure temperatures were measured for each of the formulations. The formulations were cast from toluene onto mylar, and dried in an oven at 80oC to give a .0015 in. coating.
• the adhesive tests are those commonly employed by the pressure sensitive adhesive industry.
• shear adhesion failure temperature test a l"xl" overlap of tape to a stainless steel substrate is made with a 4.5 pound roller. A 1 kg weight is hung from the tape and the assembly is placed in an oven. The temperature is increased at 40oF/hour and the temperature at which the weight drops is recorded as the SAFT.
• polyken tack test a steel probe contacts the adhesive tape with a specified force frr a 1 second dwell time. The force required to break the bond between the adhesive and the stainless steel probe is measured (g).
• the 180o peel test involves placing a length of tape on a stainless steel plate and laminating it with a 1-pound roller. The force (lb/in) required to peel the tape at a 180o angle on an Instron is recorded.
• Figure 1 illustrates the adhesive performance findings for use of the PPO product of Example 3 with SIS formulations.
• Stereon 840 (SBS) formulations with a Zonatac 105 Lite/ Shellflex 371 tackifying system were prepared for testing as hot melt adhesives. All four PPO products were used at different levels and the results of the 180° peel and shear adhesion failure temperatures are compiled in Table 2.
• Figure 2 illustrates the superior adhesive performance findings for the use of the PPO product of this invention with SBS formulations.
• the viscosity results indicate that the PPO products of the invention can be formulated into adhesive formulations for hot melts without significantly altering the viscosity profile.
• Stereon 840 (SBS) formulations with a Zonatac 105 Lite/She! Iflex 371 tackifying system were prepared for testing as hot melt adhesives and solvnet cast pressure sensitive adhesives.
• Tg 145°C
• For the hot melt adhesive viscosity, T-Peel , SAFT and PAFT were evaluated.
• the T-Peel test was performed according to the procedure of ASTM D01876-72, for both aluminum and polyethylene.
• SAFT shear adhesion failure temperature
• PAFT peel adhesion failure temperature

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• 1990
  • 1990-05-23 EP EP90909220A patent/EP0473712A1/de not_active Withdrawn
  • 1990-05-23 WO PCT/US1990/002948 patent/WO1990014396A1/en not_active Application Discontinuation
  • 1990-05-23 JP JP2508796A patent/JPH04505634A/ja active Pending
  • 1990-05-23 WO PCT/US1990/003057 patent/WO1990014397A1/en unknown
  • 1990-05-23 CA CA002056374A patent/CA2056374A1/en not_active Abandoned

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