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
  • C09J177/00—Adhesives based on polyamides obtained by reactions forming a carboxylic amide link in the main chain; Adhesives based on derivatives of such polymers
  • C09J177/06—Polyamides derived from polyamines and polycarboxylic acids
  • C09J177/08—Polyamides derived from polyamines and polycarboxylic acids from polyamines and polymerised unsaturated fatty acids

Definitions

• This invention relates to a method of improving the block resistance of adhesive compositions containing polyamide resins, especially when stored under elevated pressures and temperatures for extended periods of time, without detrimentally increasing the softening points of the compositions.
• Polyamide resins are useful for preparing adhesive compositions.
• the adhesive composition containing the polyamide resin is applied to a substrate in molten form and cooled, or from solution, emulsion or dispersion and permitted to dry.
• the adhesive composition containing polyamide resin is then "activated” by heating the adhesive composition to a temperature, referred to as the "heat seal temperature,” which must be about or above the softening point of the polyamide resins.
• Block refers to the undesirable bonding or adhesion between the adhesive and one or more substrates prior to the activation of the adhesive. The blocking generally occurs during the storage of the coated substrate in stacked or rolled form, often under elevated pressures and/or temperatures for extended periods of time.
• PCT/US94/09971 discloses a polyamide resin having flexibility, high strength and low tack containing the condensation product of:
• an acid component containing: (a) non-linear polymerized fatty acids;
• (c) optionally, about 0.5 to about 10 equivalent % polyetherdiamine.
• PCT/US94/09971, 1 was able to improve the block resistance of adhesive compositions without increasing the softening point of the adhesive compositions containing the polyamide resin to a temperature greater than a heat seal temperature of about 300°F.
• the present invention is directed to a method of improving the block resistance of adhesive compositions containing at least one polyamide resin including the steps of:
• compositions useful in the method of the present invention include the reaction products of an acid component with a substantially equivalent amount of an amine component.
• equivalent % values are determined as follows: The total number of free acid groups in the acid component added to the polymerization reaction is set equal to 100 equivalent %. The equivalent percent of amine component is then based on that of acid component; i.e., the total number of free amine groups in the amine component added to the polymerization reaction is expressed as a percentage of the total number of free acid groups.
• the acid component of the polyamide composition useful in the method of the present invention contains: (a) at least one polymeric fatty acid; and
• polymeric fatty acid or “dimer acid,” as used herein, refers to complex mixtures of polymerized acids obtained from fatty acids.
• fatty acids refers to saturated, ethylenically unsaturated and/or acetylenically unsaturated aliphatic carboxylic acids which can be naturally-occurring, synthetic or semi-synthetic.
• Polymeric fatty acids useful in the method of the present invention include those polymeric fatty acids derived from oleic acid and linoleic acids, such as those present in commercial tall oil fatty acids.
• the polymeric fatty acids useful in the method of the present invention include non ⁇ linear polymeric or oligomeric fatty acids made from addition polymerization of unsaturated tall oil fatty acids.
• the polymeric fatty acids are formed from a high percentage of dimer acid, particularly hydrogenated (saturated) dimer acid, to provide desirable physical properties such as color, thermal and oxidative stability.
• dimer acid particularly hydrogenated (saturated) dimer acid
• Preferred fatty acids include:
• the acid component contains from about 10 to about 80 equivalent % of a polymeric fatty acid.
• the acid component contains greater than about 10 to less than about 80 equivalent % of a polymeric fatty acid, such as, for example, about 15 to about 75 equivalent % of a polymeric fatty acid, about 20 to about 70 equivalent % of a polymeric fatty acid, about 30 to about 60 equivalent % of a polymeric fatty acid, about 35 to about 55 equivalent % of a polymeric fatty acid, about 35 to about 45 equivalent % of a polymeric fatty acid. More preferably, the acid component contains about 40 equivalent % of a polymeric fatty acid.
• Dicarboxylic acids useful in the method of the present invention include aliphatic, cycloaliphatic and aromatic dicarboxylic acids, and include the corresponding anhydrides, esters and acid chlorides.
• the dicarboxylic acids contain from about 2 to about 24 carbon atoms. More preferably, the dicarboxylic acids contain from about 6 to 16 carbon atoms. Even more preferably, the dicarboxylic acids contain from about 8 to 14 carbon atoms. Most preferably, the dicarboxylic acids contain from about 10 to 12 carbons.
• Aliphatic dicarboxylic acids useful in the method of the present invention include, for example, oxalic, glutaric, malonic, adipic, succinic, pimelic, suberic, azelaic, sebacic and dodecanedioic acids and mixtures thereof.
• Cycloaliphatic dicarboxylic acids useful in the method of the present invention include, for example, cyclohexane dicarboxylic acids, such and 1,3- and 1,4-cyclohexane dicarboxylic acids and mixtures thereof.
• Aromatic dicarboxylic acids useful in the method of the present invention include, for example, phthalic, isophthalic, terephthalic and naphthalene dicarboxylic acids and mixtures thereof.
• the acid component contains from about 10 to about 95 equivalent % of a dicarboxylic acid.
• the acid component contains greater than about 10 to less than about 95 equivalent % of a dicarboxylic acid, such as, for example, about 15 to about 90 equivalent % of a dicarboxylic acid, about 20 to about 85 equivalent % of a dicarboxylic acid, about 25 to about 80 equivalent % of a dicarboxylic acid, about 30 to about 75 equivalent % of a dicarboxylic acid, about 40 to about 70 equivalent % of a dicarboxylic acid, about 45 to about 65 equivalent % of a dicarboxylic acid. More preferably, the acid component contains about 60 equivalent % of a polymeric fatty acid.
• the acid component of the polyamide composition useful in the method of the present invention contains:
• Cycloaliphatic diamines useful in the method of the present invention include piperazine and derivatives thereof, including l,2-di(l-piperazinyl)propane, l,3-di-(l-piperazinyl)propane, 1,2- di-(l-piperazinyl)ethane, l,4-di-(l-piperazinyl)butane, and N-hydroxyethylpiperazine.
• the cycloaliphatic diamine compound has the formula:
• each of R,, R R 3 and R 4 is hydrogen or alkyl of 1 to about 4 carbon atoms.
• each of R privilege Rj, R 3 and R is independently hydrogren.
• Exemplary alkyl groups include, for example, methyl, ethyl, propyl, including n-propyl and i-propyl, and butyl, including n-butyl, i- butyl, t-butyl and sec-butyl.
• the amine component contains from about 60 to about 95 equivalent % of a cycloaliphatic diamine.
• the amine component contains greater than about 60 to less than about 95 equivalent % of a cycloaliphatic diamine, such as, for example, about 70 to about 95 equivalent % of a cycloaliphatic diamine, about 80 to about 95 equivalent % of a cycloaliphatic diamine, about 85 to about 95 equivalent % of a cycloaliphatic diamine. More preferably, the amine component contains about 95 equivalent % of a cycloaliphatic diamine. Ethylenediamine
• the amine component contains from greater than about 0 to less than about 20 equivalent % of ethylenediamine. Preferably, the amine component contains from about 2 to about 15 equivalent % of ethylenediamine. More preferably, the amine component contains about 10 equivalent % of ethylenediamine.
• compositions useful in the method of the present invention include the reaction products of an acid component with a substantially equivalent amount of an amine component.
• the relative quantities of the acid component and amine component are selected such that substantially equivalent numbers of reactive carboxyl and amine groups are present in the reaction mixture to produce a neutral or balance polyamide resin.
• Slight excesses of the acid component or amine component can be used. Slight excesses of carboxyl or amine are acceptable, but this ratio is preferably maintained between about 0.9: 1 to about 1:1.1.
• the polyamide resins which are arnme-terminated can be combined with an epoxy resin to form a curable thermoset adhesive composition.
• the techniques and general methods for polymerizing the acid component and the amine component of the polyamide resins useful in the method of the present invention are well known and described, for example, in U.S. Patents 3,377,303, 4,343,743 and 4,485,233, the disclosures of which are incorporated herein by reference, in their entirety.
• the adhesive compositions containing the polyamide resins useful in the method of the present invention may optionally contain other additives, such as, for example, fillers, reinforcing agents, coupling agents, colorants, odorants, other comonomers, resins, tackifiers, plasticizers, lubricants, stabilizers, antistatic agents, and the like.
• the polyamide resins of the present invention may be in the form of a hot melt, or in the form of a resin in solution, emulsion or dispersion (including an aqueous dispersion).
• the present invention is directed to a method of improving the block resistance of adhesive compositions containing at least one polyamide resin including the steps of: (1) forming an adhesive composition containing a select polyamide resin described herein above; (2) applying said adhesive composition to a first substrate; and
• the select polyamide compositions described herein are useful in a method of improving the block resistance of an adhesive composition into which it is incorporated without detrimentally increasing the softening point of the adhesive composition above a heat seal temperature of 300°F.
• the first substrate and second substrate may be the same or different and may be any material for which adhesive compositions containing polyamide resins are typically used, such as, for example, polyvinyl chloride, polypropylene, polyester, polyurethane, polycarbonate, polystyrene, wood, glass, paper and the like.
• the adhesive composition containing polyamide resin may be applied to the first substrate by conventional means, including the steps of:
• the first substrate may be adhered to the second substrate by: (1) contacting the surface of the first substrate coated with the adhesive composition containing the select polyamide resin to the second substrate; and
• the polyamide resins useful in the method of the present invention have been selected to produce an adhesive composition having a softening point less than or equal to the heat seal temperatures of from about 175°F to about 300°F, preferably from about 175°F to about 250°F, and most preferably from about 175°F to about 200°F.
• the period of time necessary to activate the adhesive composition depends upon the select polyamide resin, the heat seal temperature applied and pressure applied. Typically, the period of time necessary to activate.the adhesive composition ranges from about 1 second to about 1 minute, however, preferably the period of time ranges from about 1 to about 10 seconds.
• the amount of pressure which needs to be applied depends upon the select polyamide resin, the heat seal temperature applied and time that such temperature has been applied. Generally, the amount of pressure is from about 10 to about 100 pounds/inch 2 .
• Adhesive compositions and comparative adhesive compositions were prepared from polyamide resins in the form of an aqueous dispersion formed from the reactants (all values in equivalent %) listed in Table 1 with softening points as measured on a Mettler FP90 Central Processor and a Mettler PF83 HT Dropping Point Cell with a softening point ring at a rate of 1.5°C/minute as listed in Table 2.
• Adhesive SC 40 - 60 75 20 Adhesive SC 40 - 60 75 20 —
• the polymeric fatly acid utilized was Dimer- 14 available from Union Camp Corporation (Wayne, New Jersey) having a composition of 0.4 weight % monomer/95.6 weight % d ⁇ mer/4.08 weight % trimer and higher polymer.
• Adhesive compositions and comparative adhesive compositions prepared from polyamide resins in the form of an aqueous dispersion of Example 1 were coated on samples of 5 mil thick polyvinyl chloride (“PVC”) and air-dried overnight at room temperature.
• PVC polyvinyl chloride
• the adhesive-coated samples of PVC prepared according to Example 2 were heat sealed to uncoated PVC at varying temperatures (225°F, 250°F, 275°F and 300°F) for a dwell time of 3 seconds and at 50 pounds/inch 2 .
• T-peel adhesion tests were conducted on the Adhesive Samples using the Instron Series IV Automated Materials Testing System, at a peel rate of 12 inches/minute and at room temperature. The results are shown in Table 3 with units of pounds linear inch (with higher numbers indicating better adhesion).
• Adhesive 1 3.4 4.1 6.2 —
• Adhesive 8 2.7 4.6 4.1 Table 3 shows that those adhesives within the scope of the invention have better adhesion to the second PVC than the adhesives outside the scope of the invention.
• the adhesive-coated samples of PVC prepared according to Example 2 were applied to uncoated PVC at room temperature with the adhesive sandwiched between the two layers of PVC.
• the layered samples were placed in a Carver Press under 1000 pounds/inch 2 pressure overnight at room temperature. Block resistance testing was conducted by carefully peeling apart the layered samples both listening for any cling and observing any adhesive transfer from the coated PVC to the uncoated PVC.
• the samples were rated according to Table 4. The results are shown in Table 5.
• Adhesive 5C not tested softening point too high
• Table 5 shows that those adhesives within the scope of the invention have improved blocking relative to the adhesive outside the scope of the invention.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Polyamides (AREA)

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• 1996
  • 1996-06-10 WO PCT/US1996/010272 patent/WO1996041837A1/en not_active Application Discontinuation
  • 1996-06-10 EP EP96923301A patent/EP0847423A4/de not_active Withdrawn
  • 1996-06-10 CA CA 2224323 patent/CA2224323A1/en not_active Abandoned

Patent Citations (6)

Non-Patent Citations (1)

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