JPH0881667A - Use of lowly toxic solvent in water-based adhesive - Google Patents

Abstract

PURPOSE: To provide a waterborne adhesive for packaging and processing which is suitable for bonding a waxy substrate (e.g. a paraffin-coated carton) by compounding a specific low-toxicity solvent with an adhesive compsn. mainly comprising a vinyl acetate polymer dispersion.

CONSTITUTION: A waterborne adhesive compsn. contg. 0-20 pts.wt. mixture contg. (A) A water-base dispersion of a vinyl acetate polymer or a pure acrylic polymer in an amt. effective for imparting adhesiveness, pref. 50-90 pts.wt., (B) 0-10 pts.wt. PVA, and a plasticizer, a tackifier, a filler, and a humectant, each in an amt. of 0-20 pts.wt. and (C) 0-25 pts.wt. humectant is compounded with (D) 1-35 pts.wt. org. solvent selected from among 1-5C alkyl butyrates, d-limonene, ethylene glycol monobutyl ether, 5-20C aliph. hydrocarbon petroleum distillates, and normal paraffins, thus giving the objective adhesive. Pref., ingredient A contains 55 wt.% solids. The addition of a surfactant is effective in enhancing the penetration of the adhesive.

COPYRIGHT: (C)1996,JPO

Description

Detailed Description of the Invention

The present invention relates to water-based adhesives suitable for use on waxy substrates.

The packaging adhesives field has been dominated by water-based adhesives based on polyvinyl acetate homo-, co- or terpolymer dispersions. In many of their packaging applications, organic or inorganic solvents are water-based adhesives.
It is added to enhance the "wetting" and the ability to penetrate the support, and thereby improve the adhesion. Halogenated solvent, and especially methyl chloroform (1,1,1-
Trichloroethane) is most commonly used for those purposes, however, it has led to research for other solvents satisfying their potential environmental and health-related effects. Recent US Patent No. 5,100,94
No. 4 disclosed the effectiveness of ethylene glycol diacetate as a substitute for methyl chloroform for infiltrating and penetrating the support. However, this solvent is not completely effective as a penetrant on waxy supports.

Certain organic solvents such as lower alkyl butyrate, d-limonene, ethylene glycol monobutyl ether and certain water treated low molecular weight petroleum distillates and usually paraffin are used in water based packaging and conversion adhesives. It has been found that improved penetrability and wettability to waxy substrates is obtained, which gives properties comparable to or better than the adhesive properties achieved by methyl chloroform. . Accordingly, the present invention provides: A) a) a dispersion of a polymer selected from the group consisting of vinyl acetate and pure acrylic polymers, the dispersion being the adhesive required for use as a packaging or processing adhesive. B) i) 0 to 20 parts by weight of plasticizer; ii) 0 to 10 parts by weight of polyvinyl alcohol; iii) 0 to 20 parts by weight of tackifier; iv) filler. 0 to 20 parts by weight; v) 0 to 20 parts by weight of humectant; vi) 0 to 20 parts by weight of the mixture of i) to v); and vii) a mixture of 0 to 25 parts by weight of a thickener; and B) C. ₁ -C ₅ alkyl butyrates, d-limonene, ethylene glycol monobutyl ether, and C ₅ -C ₂₀
It relates to a water-based packaging and conversion adhesive comprising 1-35 parts by weight of an organic solvent selected from the group consisting of aliphatic hydrocarbon petroleum distillates and usually paraffin.

Suitable specific solvents are methyl butyrate,
Ethyl butyrate, propyl butyrate, n-butyl butyrate, pentyl butyrate, d-limonene, ethyl glycol, monobutyl ether and as Actrel trademark, for example, Actrel ^™ 1111L, 1160.
L, 1171L, 4493L, 3349L and 3360
L is petroleum distillate sold by Exxon Corporation and usually paraffin. Of petroleum distillates, odorless 3349L, 1111L and 1
160 L is preferred. If a low flammability rate is desired, 1111 L is more preferred; if high permeability is required, 3349 L is more preferred.

The specified solvents can be used in conventional water-based vinyl acetate or pure acrylic-based packaging or processing adhesive formulations. Surprisingly, the organic solvent used in the adhesive of the present invention, when applied to a waxy substrate,
It has been found that it can be used at substantially lower levels than required by methylchloroform (1,1,1-trichloroethane) to achieve comparable performance in the same adhesive system. A waxy support is one in which the support has at least one of the following properties: moisture barrier, water resistance,
If grease resistance, abrasion resistance, or chemical resistance is desired, it is meant to be coated with a waxy material.
As used herein, a waxy support is a support coated with a polymeric material that has been modified with low levels of wax components, such as a styrene / acrylic or polyethylene material that has been modified with a wax emulsion. Not intended to be inclusive. Although the adhesives of the present invention exhibit adhesion to non-waxed substrates comparable to or better than conventional packaging and processing adhesives, the advantages of the adhesives of the present invention are: Best realized when used to bond sheet-like supports.

The exact formulation of the adhesive will vary depending on the particular end use. Generally, the adhesive comprises a dispersion of vinyl acetate or pure acrylic polymer. The vinyl acetate polymer can be a polyvinyl acetate homopolymer, or a copolymer or terpolymer of up to 80% of other ethylenically unsaturated copolymerizable comonomers with vinyl acetate. Examples of such comonomers are C ₁ -C ₉ esters of α-olefins and mono- or dicarboxylic acids, especially esters of acrylic, methacrylic and maleic acids. Ethylene, 2-ethylhexyl acrylate and dibutyl maleate are the most commonly used comonomers. Pure acrylic polymers are acrylic monomers such as acrylic acid, methacrylic acid, is prepared from C ₁ -C ₁₂ alkyl esters and C ₁ -C ₈ alkyl substituted acrylamides and methacrylamides of acrylic or methacrylic acid.

The amount of vinyl acetate or pure acrylic polymer dispersion used in the adhesive is effective in imparting the adhesive properties required for use as a packaging or processing adhesive. The actual amount used will depend, for example, on the following factors, such as the particular polymer used in the dispersion and the particular application for which the adhesive may be used: type of support, application conditions, end use, etc. Will. One of ordinary skill in the art will be able to ascertain the particular level of polymer dispersion required for the particular conditions and environment surrounding a particular application. Vinyl acetate or pure acrylic polymers are generally used at 2% based on the total weight of the adhesive composition.
It is present in the adhesive in the form of an aqueous dispersion at a level of 0 to 99 parts by weight, preferably 50 to 90 parts by weight. The polymer dispersion itself is about 50-70% by weight, preferably about 55% by weight.
Would have a solids level of. Optionally, the vinyl acetate or pure acrylic polymer dispersion comprises polyvinyl alcohol as a protective colloid, or on the other hand polyvinyl alcohol may be added to the water-based adhesive formulation. When present, polyvinyl alcohol is used at a level of 0.1 to 10 parts by weight total adhesive formulation, preferably 0.5 to 5.0 parts by weight. In addition to polyvinyl alcohol,
Other stabilizers, such as surfactants, cellulosic materials,
For example, hydroxyethyl cellulose, starch or combinations thereof can be utilized during polymerization.

Other additives commonly used in packaging adhesives such as plasticizers, defoamers, preservatives, thickeners, rheological modifiers, humectants, fillers and tackifiers are conventional. Amounts can be used and water can be added to obtain the desired applied viscosity.

If present, one or more plasticizers commonly used in vinyl acetate based water based packaging adhesives may be used in the adhesive formulation. Typical plasticizers are acetyl tributyl citrate, butyl benzyl phthalate, butyl phthalyl butyl glycolate, dibutyl phthalate, dibutyl sebacate, diethyl phthalate, diethylene glycol dibenzoate, dipropylene glycol, dipropylene glycol dibenzoate, ethyl phthalyl. Ethyl glycolate, ethyl-p-toluenesulfonamide, hexylene glycol, methylphthalylethyl glycolate, polyoxyethylene aryl ether, tributoxyethyl phthalate, triethylene glycol polyester of benzoic acid and phthalic acid. Of those plasticizers, dibenzoate type, phthalate, liquid polyester or sulfonated types are preferred. The plasticizer is generally 2 to 20 parts by weight, preferably 3
Used in an amount of ~ 15 parts by weight.

The tackifier, if present, is generally 4
It will be used in dispersed form in an amount of up to about 50 parts by weight, preferably 2 to 20 parts by weight, with a solids content of 0-65%. Typical tackifiers include coumarone-indene, ester gum, gum rosin, hydrocarbon resins, hydrogenated rosin,
Phenol-modified hydrocarbon resin, rosin ester,
Tall oil rosin, terpene phenolic resin, terpene resin, toluene-sulfonamide-formaldehyde resin and wood rosin.

A suitable thickening agent is an originate.
inates), bentonite, sezein, fumed silica, guar gum, tragacanth gum, hydroxyethyl cellulose, locust bean gum, methyl cellulose,
Included are polyacrylates (ammonium, potassium, sodium), polyvinyl alcohol, sodium carboxymethyl cellulose, and starch, and, if present, will be used in amounts up to about 25 parts by weight.

Useful fillers include bentonite, calcium carbonate, calcium silicate, clay, mica, nut flour, silica, talc, uncooked starch and wood flour, and, if present, up to about 20 parts by weight. Will be used in quantity.

Suitable moisturizers include calcium chloride, diethylene glycol, glycerin, hexylene glycol,
Propylene glycol, magnesium chloride, sodium nitrate, sorbitol, sucrose and urea are included and, if present, will be used in amounts up to about 20 parts by weight.

In order to enhance the penetration effect of the adhesive, it is preferable to mix the adhesive with 0.05 to 5.0 parts by weight of a surfactant. Surfactants can be one or more anionic, cationic, amphoteric or nonionic surface-active compounds. Suitable anionic emulsifiers are, for example, alkyl sulfonates, alkylaryl sulfonates, alkyl sulphates, hydroxylalkanol sulphates, alkyl and alkylaryl disulfonates,
Sulfonated fatty acids, sulfated and phosphated polyethyoxylated alkanols and alkylphenols, and esters of sulfosuccinic acid. Suitable cationic emulsifiers are, for example, alkyl quaternary ammonium salts and alkyl quaternary phosphonium salts. One type of suitable nonionic emulsifier is a straight or branched chain alkanol having 6 to 22 carbon atoms, or an alkylphenol, higher fatty acid, higher fatty acid amine or primary and secondary higher alkylamine. It is an addition product of 5 to 50 mol of ethylene oxide to be added. Other suitable nonionic emulsifiers are one or more block copolymers of ethylene oxide and propylene oxide.

In order to formulate the adhesive with improved adhesion and penetration to waxy substrates, one or more of the specific disclosed solvents may be added based on the total weight of the adhesive composition. ~ 35 parts by weight, preferably 5-30 parts by weight, is added to the adhesive. The actual amount of solvent used will depend on the particular solvent selected and the particular substrate to which the adhesive is applied. If the support has a thin wax coating applied to it or no wax coating applied to it, the solvent may be used in amounts as low as 1% by weight. If the support has a thick waxy coating applied to it, the solvent is preferably used in an amount of at least 5% by weight. In addition to providing a non-hazardous alternative to methyl chloroform, some of these solvents, such as Ac
trel1111L, 3349L and 1160L have the advantage of odorlessness, a desired property in the packaging industry.

The resulting adhesive, when properly formulated, is in any of the packaging and processing applications in which water-based adhesives are commonly used, such as box and carton forming and sealing, tube winding, bag making, gluing. It can be used in wraps, paper and flexible film laminates. However, it is realized that the improved adhesion and penetration properties of the adhesives of the present invention are best when the adhesives are used to bond waxy substrates.

Typical waxy substrates include, for example, paraffin wax coated cardboard and various nameplates of paraffin wax coated paper. Typical examples of products made from waxy substrates are paper bags, milk and juice cartons, beverage cups, containers for transport products and the like, as well as water resistance, grease resistance, abrasion resistance, It includes, but is not limited to, other applications where properties such as chemical resistance, moisture impermeability are desired. The waxy support and thus the products produced therefrom have applied a packaging or processing adhesive to a part thereof. Depending on the particular application, the waxy support may be coated on substantially all of one surface, or on both sides. On the other hand, the adhesive may be applied as beads, whereby the unimportant parts of the support apply them to them. Those skilled in the art will readily ascertain those applications for which the use of the adhesives of the present invention is advantageous. Any conventional method for applying an adhesive to a particular substrate can be used. Those methods are well known in the field of packaging and processing adhesives.

[0018]

EXAMPLES Water-based adhesives suitable for packaging and processing use were prepared with the disclosed solvents / penetrants and tested for improved adhesion and substrate penetration.
The test consisted of bonding the two substrates with an adhesive and pulling the bond apart and examining the extent of fiber tear. A high percentage of fiber tear indicates high adhesion.

An amount of adhesive to be tested is applied to one support using a Bird, wire rod or other applicator to mimic the end use application method, and a second
Support was placed on top of the support. Pressure was applied using a hand roller and the bond was allowed to dry for at least 24 hours. The bond was then pulled apart and the degree of fiber tear was recorded as a percent.

The performance of the test adhesive on various substrates was compared to that of a control adhesive of the same formulation without solvent. The test adhesive was also compared to a comparative adhesive using ethylene glycol diacetate and 1,1,1-trichloroethane as solvents. Results are relative to controls on the same support, and absolute results will vary depending on ambient conditions in the room.

The adhesive was prepared as follows: When used, the polyvinyl alcohol was dispersed in water and allowed to reach 85-91 ° C (185-195 ° C) for 1 hour until smooth.
F) with stirring and then 60 ° C. (140 ° C.)
Cooled to below ° F). While stirring one or more commercially available polyvinyl acetate or ethylene / vinyl acetate dispersions,
Added to the polyvinyl alcohol solution for 30 minutes. Next, in order, a plasticizer, diethylene glycol dibenzoate, a solvent, a defoaming agent, a surfactant and a preservative were added.
The whole mixture was stirred for 1 hour and diluted with water to the desired viscosity. If polyvinyl alcohol was not used, the various additives, if present in the formulation, were added sequentially as above, the mixture was stirred for 1 hour and diluted to the desired viscosity.

Example 1: Adhesive Containing n-Butyl Butyrate An adhesive prepared as described above and designated Sample Adhesive I is for use on corrugated board coated with a wax emulsion modified polyethylene blend. Based on standard common packaging adhesives. n-Butyl butyrate was the solvent and support penetrant. Unless otherwise noted, all parts by weight are based on the total weight of the adhesive formulation. Sample adhesive I had the following composition in parts by weight: Water 5.4 Polyvinyl alcohol ^{0.45 Duroset R C-325 45.0 Resyn} R 1025 27.0 Plasticizer 11.7 Defoamer 0.27 Surfactant 0.20 Preservative 0.09 n-Butyl butyrate 10.0 10.0 Amount of water to adjust to cps

[0023] Duroset ^R C-325 is prepared by continuous polymerization method, and National Starch and Chem
Polyvinyl acetate dispersion available from ical Company, Bridgewater, New Jersey. Reyn ^R 1025
Is prepared by a batch polymerization method, and National S
Polyvinyl acetate dispersion available from Tarch and Chemical Company. The plasticizer is Velsicol Chemical Corp.
It was a mixture of diethylene, dipropylene and glycol dibenzoate sold under the trademark Benzoflex 50 by oration. Defoamer is Henkel
Trademark Foamaste by Corporation
r III / Fomaster B, a commercial product sold. Surfactant is Cytec Ind
The trademark Aerosol OT 75 by ustries
It was a product sold as a percentage. The preservative is Reh
Trademark Kath by m & Hoas Company
It was a product sold as on LX 1.5%.

Sample Adhesive I was used to adhere sulfate bleached solids (white bleached virgin paper fibers) and kraft paper to various substrates. The bond was then tested for the degree of fiber tear. A control without n-butyl butyrate, but with the same formulation as Adhesive I, was simultaneously tested. The results are shown in Table 1 and Adhesive I with the addition of n-butyl butyrate showed improved adhesion and penetration on waxy and non-waxed substrates. Indicates that.

[0025]

[Table 1] * Product of Michelman Company, Cincinnati, Ohio.

Example 2: Adhesive containing d-limonene and ethylene glycol monobutyl ether for use on a waxy coated substrate. A series of adhesives containing ethylene / vinyl acetate dispersions as solvent and penetrant and d-limonene or ethylene glycol monobutyl ether were prepared as described above and designated as samples IIa, b, c and d. The samples were used to bond paraffin wax coated paper to white wood pulp kraft paper and tested for improved adhesion and penetration by examining the wax coated paper for fiber tear. Same composition,
However, a control without solvent and penetrant was tested simultaneously. None of the controls showed any fiber tear. All samples showed 100% fiber tear.
The composition of the sample is shown in Table 2. The surfactants, preservatives and defoamers were the same as in Example 1.

[0027]

[Table 2]

Example 3: Adhesive containing petroleum distillates for use on wax coated substrates. A series of adhesives containing an ethylene / vinyl acetate dispersion with solvent and petroleum distillate as penetrant were prepared as described above and designated as Samples IIIa-k. The samples were used to bond paraffin wax coated paper to white wood kraft paper and tested for improved adhesion and penetration by examining the wax coated paper for fiber tear. Have the same formulation, but
However, a control without solvent and penetrant was tested simultaneously. None of the controls showed any fiber tear. All samples showed 100% fiber tear.
The composition of the sample is shown in Table 3.

[0029]

[Table 3]

The plasticizer is the same as in Sample I. Actrel solvents are available from Exxon Corporation, Housto
n, a solvent available from Texas. Actrel
1111L, 1160L and 1171L are 150 °-
290 ℃ C ₉ -C _16, which is water treatment (bydrotreated) having a boiling range of (302 ° ~554 ° F)
Petroleum distillate. Actrel 4493L is normal paraffin and 35 ° C to 435 ° C (95 ° to 653 °).
A combination of linear saturated C ₅ -C ₂₀ hydrocarbons having a boiling point in the range of F). Actrel 3360L and 334
9L is a water treated heavy naphtha (petroleum) C having a boiling point in the range of 65 ° to 230 ° C (149 ° to 446 ° F).
_6- C _{13 is an} aliphatic hydrocarbon distillate.

Example 4: Adhesive containing petroleum distillates for use on wax coated substrates. A series of adhesives containing an ethylene / vinyl acetate dispersion as solvent and a penetrant and petroleum distillate were prepared as described above and designated Samples IVa-c. A comparative example was prepared using 1,1,1-trichloroethane (TCE) instead of petroleum distillate as the solvent and penetrant and was designated Samples IVd-f. Instead of petroleum distillate as solvent and penetrant, ethylene glycol diacetate (E
GDA) was used to prepare a comparative example and sample IV
They are named g to i. All samples were used to bond paraffin wax coated paper to white wood pulp kraft paper and tested simultaneously for improved adhesion and penetration by examining the wax paper for fiber tear. Sample composition and their respective%
Fiber tear is shown in Table 4.

[0032]

[Table 4]

A series of adhesives containing ethylene / vinyl acetate dispersions and petroleum distillates as solvents and penetrants were prepared as described above and designated as samples Va-d.
A comparative example without solvent was prepared and named Sample Ve. All samples were simultaneously tested for improved adhesion and penetration by adhering paraffin wax coated paper to white wood pulp kraft paper and examining the wax paper for fiber tear. The compositions of the samples and their respective% fiber tears are shown in Table 5.

[0034]

[Table 5]

Examples of these are the adhesiveness and penetrability of water-based packaging and processing adhesives, especially in the case where bonding (adhesion) of waxy supports is required, in particular non-toxic organic solvents. It can be improved by the addition of.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Paul P. Paretti USA, New Jersey 08867, Pittstown, Hill Hello Drive Live, Box 344, Rural Delivery # 3

Claims (19)

[Claims] 1. A water-based packaging and processing adhesive comprising: a) a) a dispersion of a polymer selected from the group consisting of vinyl acetate and pure acrylic polymers, the dispersion being for packaging or processing. Present in an amount effective to impart the adhesive properties required for use as an adhesive for use; b) i) 0 to 20 parts by weight of plasticizer; ii) 0 to 10 parts by weight of polyvinyl alcohol; iii ) 0 to 20 parts by weight of tackifier; iv) 0 to 20 parts by weight of filler; v) 0 to 20 parts by weight of humectant; vi) 0 to 20 parts by weight of mixture of i) to v); and vii) thickening. A mixture containing 0 to 25 parts by weight of the agent; and B) C ₁ -C ₅ alkyl butyrate, d-limonene, ethylene glycol monobutyl ether, and C ₅ -C _20.
An adhesive comprising 1 to 35 parts by weight of an organic solvent selected from the group consisting of aliphatic hydrocarbon petroleum distillates and usually paraffin. 2. Vinyl acetate, wherein said polymer comprises up to 80% of another ethylenically unsaturated copolymer comonomer selected from the group consisting of α-olefins and C ₁ -C ₉ alkyl esters of mono- or dicarboxylic acids. The adhesive according to claim 1, which is a copolymer. 3. The polyvinyl alcohol is 0.5 to
The adhesive of claim 1 present in an amount of 5.0 parts by weight. 4. The adhesive according to claim 1, wherein the plasticizer is present in an amount of 2 to 20 parts by weight. 5. The adhesive of claim 1, wherein the tackifier is present in an amount of 2-10 parts by weight. 6. The adhesive according to claim 1, further comprising 0.05 to 5.0 parts by weight of a surfactant. 7. The adhesive according to claim 1, wherein the dispersion is present in an amount of 20 to 99 parts by weight. 8. The adhesive according to claim 1, wherein the solvent is present in an amount of 5 to 30 parts by weight. 9. A product having a packaging or processing adhesive composition applied to a portion thereof, said adhesive composition being selected from the group consisting of A) a) vinyl acetate and a pure acrylic polymer. A dispersion of a polymer, the dispersion being present in an amount effective to impart the adhesive properties required for use as a packaging or processing adhesive; b) i) a plasticizer 0-20. Parts by weight; ii) polyvinyl alcohol 0-10 parts by weight; iii) tackifier 0-20 parts by weight; iv) filler 0-20 parts by weight; v) moisturizer 0-20 parts by weight; vi) i) -v. Vii) a mixture containing 0 to 25 parts by weight of a thickening agent; and B) C ₁ -C ₅ alkyl butyrate, d-limonene, ethylene glycol monobutyl ether, and C ₅ -C. ₂₀
A product comprising from 1 to 35 parts by weight of an organic solvent selected from the group consisting of aliphatic hydrocarbon petroleum distillates and usually paraffin. 10. Vinyl acetate, wherein the polymer comprises up to 80% of an ethylenically unsaturated copolymer and another ethylenically unsaturated copolymer comonomer selected from the group consisting of C ₁ -C ₉ alkyl esters of mono- or dicarboxylic acids. The product of claim 9 which is a copolymer. 11. The polyvinyl alcohol is 0.5 to
The product of claim 9 present in an amount of 5.0 parts by weight. 12. A product as set forth in claim 9 wherein said plasticizer is present in an amount of 2 to 20 parts by weight. 13. A product as set forth in claim 9 wherein said tackifier is present in an amount of 2 to 10 parts by weight. 14. The product of claim 9 further comprising 0.05 to 5.0 parts by weight of a surfactant. 15. The product of claim 9 wherein the dispersion is present in an amount of 20-99 parts by weight. 16. A product as set forth in claim 9 wherein said solvent is present in an amount of 5 to 30 parts by weight. 17. The article of claim 9 comprising a waxy support. 18. A product according to claim 17, which is selected from the group consisting of paraffin coated paper bags, cartons, beverage cups and containers. 19. A method for improving the adhesion of vinyl acetate or pure acrylic packaging or processing adhesives.
_{1 to} 35 parts by weight of an organic solvent selected from the group consisting of C ₁ -C ₅ alkyl butyrate, d-limonene, ethylene glycol monobutyl ether and C ₅ -C ₂₀ aliphatic hydrocarbon petroleum distillate and normal paraffin are adhered. A method comprising adding to the agent.