JP2882466B2 - Method for improving the adhesion of polymer surfaces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a method for improving the adhesion of negatively charged or polar polymers.

BACKGROUND OF THE INVENTION The use of water-based emulsions / suspensions for coating and adhesive applications is a large commercial business. In the field of adhesives, emulsions based on styrene-butadiene, vinyl acetate and acrylates are commonly used in a variety of applications including film packaging, carpet backing, pressure sensitive adhesives, furniture assembly, vinyl laminates, general purpose glues / adhesives and food packaging. Used for applications. The bonding of polymer substrates to woven or nonwoven products or other porous products, including paper, is an important application.

[0003] Film lamination uses aqueous vinyl acetate or acrylic emulsions to produce poly (ethylene terephthalate) (Mylar ^™ ), polyethylene,
Polypropylene, poly (vinylidene chloride) (Sara
^nTM ), polystyrene, cellulose acetate, aluminum foil and poly (vinyl chloride) used to bond coated or uncoated paper to various films. The properties required for film lamination include high solids, film clarity, water resistance, emulsion shear stability, and the ability to be sprayed, extruded or rolled at high line speeds (eg, shear rates). Wet tack adhesion (the ability of the adhesive to adhere to the surface prior to water evaporation) is desired in the case of paper-paper or paper-film lamination. Dry tack adhesion is important when bonding two non-porous surfaces. Of course, the film
Paper, film-foil, paper-foil or film-film lamination is most important. The extrusion lamination method is a method in the case where adhesion between different supports is important, and an improvement is desired. In this method, two surfaces are brought together while simultaneously extruding a layer of a molten polymer, such as polyethylene, between two films. Typically, as an independent operation before laminating, apply an adhesion promoting primer to one or both of the film surfaces,
Improves fixation to extruded polyethylene or other hot melt polymer adhesive layers.

[0004] Frequently, the aqueous emulsions have limited adhesion to polymer films. One method used to improve adhesion is by surface treatment of the polymer film, for example by plasma treatment, corona discharge or acid immersion. Another method used to improve adhesion involves adding a fixative to the adhesive emulsion. US Patent 3,033,707
No. 3,096,602, No. 3,140,196
Nos. 3,230,135 and 3,361,586 all teach the use of polyalkyleneimine polymers, such as polyethyleneimine, as fixatives in various lamination or heat sealing applications.
Further, US Pat. No. 5,326,809 discloses poly (vinyl alcohol / vinyl amine) useful as a protective colloid for vinyl ester and acrylate based polymer emulsions having improved properties as wood adhesives. A method for manufacturing is taught.

SUMMARY OF THE INVENTION The present invention is a method for improving the adhesion of an adhesive material to the surface of a negatively charged or polar polymer. The surface of the polymer is coated with a solution consisting of about 0.0001 to 10% by weight of a vinylamine-containing polymer or salt thereof. The coating is performed such that at least one monolayer of the vinylamine-containing polymer or salt thereof adheres to the polymer surface. After coating the polymer surface with the vinylamine-containing polymer or salt, the adhesive material was applied.

[0006] Surprisingly, even a monolayer of polyvinylamine or a vinylamine copolymer containing a polymer of a vinylamine salt, applied to the surface of a polar or negatively charged polymer, has a high molecular weight directly added to the adhesive emulsion. It has been found that adhesion improvements similar to those obtained with the use of a fixing agent are obtained. This gives the same desired adhesion as the prior art requires large amounts of fixer, even though very little vinylamine-containing polymer is used.

[0007] In addition to improving adhesion, monolayers of vinylamine-containing polymers can be increased in thickness by making the anionic polymer / poly (vinylamine) dilute solution dip into a tacky type film. . These tacky films resist water extraction and provide modified surface properties, such as improved printability, antistatic performance, anti-fog properties, friction, antithrombogenicity and biocompatibility.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides poly (vinylamine), such that at least one monolayer resistant to removal by water adheres to the surface.
Treating the surface of the polar or negatively charged polymer with a dilute solution of a polymer comprising a copolymer of poly (vinylamine) or a salt of poly (vinylamine).
The resulting surface exhibits improved adhesion to typical adhesive materials such as film lamination emulsion adhesives and hot melt adhesives.

[0009] Solutions of vinylamine-containing polymers can be applied to any suitable film or foil to improve adhesion. The method comprises the steps of producing a film-paper, film-using a wet or dry lamination method.
Applicable to lamination of cloth, film-foil, paper-foil, foil-cloth, film-film and foil-foil. Suitable films for the present method include, but are not limited to, polypropylene, polyethylene, cellulose resin, polyamide, poly (vinylidene chloride), poly (vinyl chloride), poly (ethylene terephthalate), and the like. On the foil,
Includes, but is not limited to, aluminum and copper. Papers include, but are not limited to, coated and uncoated papers, cardboard, unbleached and bleached papers. The fabric can include both woven and non-woven (eg, spunbonded) components, either synthetic or natural fibers. Typically, any of the above substrates treated with a solution of a vinylamine-containing polymer need to be either polar or negatively charged. Therefore,
Prior to applying the vinylamine solution, the substrate or at least its surface may need to be modified to form anionic groups that can interact with the poly (vinylamine) or vinylamine copolymer.

[0010] Any conventional processing method capable of imparting a negative charge to the surface of the film to be coated can be used. For example, a poly (olefin) (eg, polyethylene or polypropylene) can be corona discharged to obtain a negatively charged surface. For polyolefins and other polymers of the present invention, plasma treatment can also be used. Also, an acid treatment (eg, H ₂ SO ₄ , HNO ₃ and mixtures thereof) can be used (by immersion) to obtain the desired surface modification. Fluoroxidation is a particularly effective method of obtaining the desired surface modification. In addition, there are various methods of ozone, chlorination, sulfonation, acrylic acid grafting, maleic anhydride grafting, surface oxidation, electron beam exposure, radiation irradiation, and UV exposure in the presence of oxygen. It can be carried out. Typically, the polar polymer does not have to be treated before applying the solution of the vinylamine-containing polymer.

The solution applied to the polymer surface must contain from about 0.0001 to 10% by weight of a vinylamine-containing polymer or a salt of a vinylamine-containing polymer, including copolymers thereof. Typically, the vinylamine-containing polymer is in an aqueous solution, water / alcohol or alcohol. Vinylamine-containing polymers have a wide range of molecular weights, typically between 5,000 and 1,000.
It can have a range of 0,000. In the case of a solution comprising a copolymer of vinylamine, generally the copolymer may comprise either a vinylamine or a vinylamine salt, typically a monomer unit which copolymerizes with the corresponding amide. Examples of monomer units include vinyl acetate, vinyl alcohol, acrylic acid, maleic anhydride,
Includes N-vinylpyrrolidone, and other water-soluble monomers. Such copolymers contain at least 5 mol% vinylamine. Also, salts of vinylamine-containing polymers can be used, including, for example, polyvinyl ammonium carbonate and polyvinyl ammonium chloride.

[0012] The vinylamine containing polymers of the present invention can be prepared by any of the conventional synthetic techniques known in the art. For example, poly (vinylamine) can be made by synthetic techniques generally shown in U.S. Pat. No. 4,421,602. In addition, a process for preparing vinylamine / vinyl alcohol copolymers is described in US Pat.
No. 492.

The solution of the vinylamine-containing polymer can be applied to the polar or negatively charged polymer surface in any suitable manner. For example, a dilute solution can be sprayed onto the polymer surface and optionally dried. Instead, use the roll coating method,
Alternatively, the polymer can simply be immersed in the solution. With either technique, the coated polymer is optionally rinsed and / or dried before applying the adhesive material. The solution applied to the polymer surface must be dilute, i.e., from about 0.0001% to 10% by weight of the vinylamine-containing polymer, based on the total weight of the solution. The preferred concentration within this range depends on the method of application. The thickness of the applied vinylamine layer can be from a monomolecular thickness, ie, as thin as 2 nm to about 50μ.

To improve the spreading and wetting of the surface of the polymer being modified, additives such as alcohols, surfactants, solvents, defoamers, thickeners, and other water-soluble polymers, such as poly (vinylamine) ) Or a vinylamine-containing polymer aqueous solution. This is necessary in some cases where the vinylamine polymer cannot even be dispersed on the surface because the particular polymer is hydrophobic.

The adhesive material applied to the coated polymer surface is typically an emulsion adhesive or a hot melt adhesive. Examples of suitable emulsion adhesives include natural rubber, styrene / butadiene, chloroprene, vinyl esters, acrylate emulsions and the like. Polyethylene is a commonly used hot melt adhesive. The particular choice of adhesive depends on the particular application for which the adhesive will be used, and lamination applications are one of the more common applications.

The surface of various polymers modified with vinylamine-containing polymers can be further modified by applying an anionic polymer. Anionic polymers can be deposited on surface monolayers that resist water extraction and improve adhesion to certain films. If enhanced adhesion is desired, the process can be repeated to form a layer of poly (vinylamine) / anionic polymer / poly (vinylamine). A preferred anionic polymer is poly (acrylic acid).

The present invention is primarily concerned with film lamination applications, but can also be used to modify film or metal surfaces. Using a negatively charged surface and immersing the surface in a dilute solution containing poly (vinylamine) or vinylamine copolymer, it is believed that at least one monolayer adheres. Further rinsing can remove everything except the monolayer. This layer can be increased in thickness by an alternative anionic polymer / poly (vinylamine) dilute solution dipping. The resulting extremely thin coating can withstand water extraction, resulting in modified surface properties. These properties include, but are not limited to, improved printability, antistatic behavior, anti-fog properties, friction, antithrombogenicity and biocompatibility.

The following examples are provided to better illustrate the present invention, but are not intended to be limiting.

Example 1 The polymer was dissolved in deionized water at room temperature to produce a 0.1% by weight solution. Corona-treated oriented polypropylene (O
PP) and untreated OPP films in dilute solution
Soaked for minutes. Remove film and place in deionized water bath
Placed for minutes. The film was removed from the water bath and hung with binder clips for 24 hours at laboratory conditions (（70 ° F., 40-55% relative humidity). Make a T-peel test specimen,
Tested according to ASTM method D-413. Airflex 40
0 ^R (vinyl acetate-ethylene copolymer emulsion (Tg = 0 ° C., 55% solids)) was applied to a 2-inch wide fabric substrate using a # 40 wire-wound rod.
Using a roller weighing 7 pounds (3.18 kg),
The non-porous substrate was adhered to the cloth substrate. Specimens were placed for 24 hours at 7
Conditioned at 5 ° F (24 ° C) and 50% relative humidity. T-peel values were measured on an Instron 1011 at a crosshead speed of 2 inches / minute (5.08 cm / minute). The test results are summarized in Table 1. Control samples were not treated at all with the dilute polymer solution.

[0020]

[Table 1]

Example 2 Polyvinylamine and Polymin P (polyethyleneimine (PEI) available from BASF) were each dissolved in water /
Dilution in isopropanol (IPA) produced a solution of polyvinylamine and Polymin P to give 5% active primer and 5% IPA. IPA was used as a wetting agent. The primer solution was prepared using a # 3 wire rod as shown in Table 2.
And dried at 75 ° F.
A 1 mil low-density polyethylene (PE) film with a corona discharge treatment on one side was used as a lamination adhesive to simulate extrusion lamination. Sandwiching a PE film between two sheets of coated film,
Heat sealed at 300 ° F., 30 psi for 2 seconds. PE
T-peel adhesion of the coated film to the untreated side of
The same day was performed on the Instron at a crosshead speed of 12 inches / min. The results in Table 2 show that PVAm provides comparable or better adhesion than PEI over a large area of the surface.

[0022]

[Table 2]

Most of the films used are commercial grade polypropylene (P) used in the flexible packaging industry.
P). 135 lb cardboard is similar to extrusion coated with polyethylene to make a milk carton stock. In the latter method, PEI was used as a primer to fix the polyethylene to the paperboard. Sample 13920-30
A is a carbonate of polyvinylamine produced by saturating an aqueous solution of an amine with CO ₂ . The final product contained of CO ₂ 39% by weight. In each case, polyvinylamine is equivalent in performance to PEI (Polymin P),
Or it turned out to be better. Carbonate Mobil
PE on all tested surfaces except 100 LCM-W
It was better than I. Carbonates have significant economic advantages over PEI or polyvinylamine.

Example 3 At room temperature, a polymer was dissolved in deionized water to produce a 0.1% by weight solution of PVAm. The corona treated Mylar film was immersed in the dilute solution for 1 minute. The film was removed and placed in a deionized water bath for 1 minute. The film was removed from the water bath and placed under laboratory conditions (~ 70 ° F, 40-5 relative humidity).
5%) for 24 hours with binder clips. T
-Peel specimens were made and tested according to ASTM method D-413. Using a No. 40 wire wrapping rod, Ai
the rflex 400 ^R was applied to the fabric substrate of the two-inch wide. The non-porous substrate was bonded to the fabric substrate using a roller weighing 7 pounds (3.18 kg). Test specimen at 75 ° for 24 hours
Conditioned at F (24 ° C.) and 50% relative humidity.
T-peel values were measured using an Instron 1011 at a crosshead speed of 2 inches / minute (5.08 cm / minute). The test results summarized below show that Mylar, which was immersed in a dilute PVAm solution and then subjected to corona discharge treatment, had improved T-peel adhesion compared to the control. For comparison, the same method was performed using untreated Mylar. The results are shown in Table 3 below.

[0025]

[Table 3]

Example 4 At room temperature, the polymer was dissolved in deionized water and PVOH / P
A 0.1% by weight solution of the VAm copolymer (12 and 20 mole% VAm) was prepared. A corona-treated oriented polypropylene (OPP) film was immersed in the dilute solution for 1 minute. The film was removed and placed in a deionized water bath for 1 minute. The film was removed from the water bath and lab conditions (~ 70
(° F., relative humidity 40-55%) for 24 hours with binder clips. Make T-peel test specimens, ASTM
Tested according to Method D-413. Airflex 400 was applied to a 2 inch wide fabric substrate using a # 40 wire wrapping rod. The non-porous substrate was bonded to the fabric substrate using a roller weighing 7 pounds (3.18 kg). The specimens were conditioned at 75 ° F. (24 ° C.) and 50% relative humidity for 24 hours. T-peel values were measured using an Instron 1011 at a crosshead speed of 2 inches / minute (5.08 cm / minute). The test results summarized below show that the T-peel strength of the prepared surface was moderately improved compared to the control sample.

[0027]

[Table 4]

Example 5 At room temperature, a polymer was dissolved in deionized water to produce a 0.1% by weight solution of PVAm. A corona treated polyethylene (PE) film was immersed in the dilute solution for 1 minute. The film was removed and placed in a deionized water bath for 1 minute. The film was removed from the water bath and hung with binder clips for 24 hours at laboratory conditions (（70 ° F., 40-55% relative humidity). A T-peel test piece was prepared and subjected to ASTM method D-4.
Tested according to 13. Airflex 400 was applied to a 2 inch wide fabric substrate using a # 40 wire wrapping rod. The non-porous substrate was bonded to the fabric substrate using a roller weighing 7 pounds (3.18 kg). 24 specimens
Conditioned at 75 ° F (24 ° C) and 50% relative humidity for hours. The T-peel value was 2 using Instron 1011.
Measured at a crosshead speed of inches / minute (5.08 cm / minute). The test results summarized in Table 5 show that for polyethylene immersed in a PVAm dilute solution and corona discharged,
This shows improved T-peel adhesion (indicated as substrate breakage) compared to the control.

[0029]

[Table 5]

Example 6 A solution of polyvinylamine and polyethyleneimine was coated and tested as in Example 2 above. ICI Inc Me
A coating was applied to the untreated side of the linex 813-48 polyester film (this film is supplied with a proprietary coating on one side). The heat sealed samples were aged at 40 ° C. and 90% relative humidity for 2 hours and 1 week. Quite unexpectedly, the sample containing PVAm
Although adhesion was improved by humidity aging, the polyethyleneimine sample lost most of the adhesion. The results are shown in Table 6 below.

[0031]

[Table 6] Having thus described the invention, what is considered appropriate herein with reference to the present patent is set forth in the following claims.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Jeffrey Alan Kufal New Jersey, USA 08822. Flemington. Leeds Road 6 (72) Inventor Walter Lewis Lens 18062, Pennsylvania, USA. Larch Lane 6391 (72) Inventor Frank Vietow Dieste Fano, 18062, Pennsylvania, USA. JP-A-8-217818 (JP, A) JP-A-7-188134 (JP, A) JP-A-7-164603 (JP, A) JP-A-6-298855 (JP, A) JP-A-6-206913 (JP, A) JP-A-4-2885 (JP, A) JP-A-56-158233 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09J 5/02 C09J 139/00-139/02

Claims (7)

(57) [Claims] 1. A method for improving the adhesion of an adhesive substance to the surface of a negatively charged or polar polymer, the method comprising the steps of: adding a vinylamine to the surface of the negatively charged or polar polymer. Coating said polymer surface with a solution consisting of 0.0001 to 10% by weight of a vinylamine-containing polymer or a salt thereof such that at least a monolayer of the containing polymer or salt adheres, and then coating the resulting coated polymer surface with A method comprising applying the adhesive substance. 2. The method of claim 1, wherein said vinylamine-containing polymer is polyvinylamine. 3. The method of claim 1, wherein the vinylamine-containing polymer is a vinylamine / vinyl alcohol copolymer.
the method of. 4. The method of claim 1, wherein said vinylamine-containing polymer is a copolymer of vinylamine and a monomer unit selected from the group consisting of acrylic acid, maleic anhydride, N-vinylpyrrolidone and other water-soluble monomers. 5. The method according to claim 1, wherein the negatively charged or polar polymer is selected from the group consisting of surface-modified polyolefin, surface-modified poly (ethylene terephthalate), poly (amide), cloth and cardboard. the method of. 6. The method of claim 1, wherein said adhesive material is an emulsion adhesive. 7. The vinylamine-containing polymer solution,
The method of claim 1 further comprising an additive selected from the group consisting of wetting agents, surfactants, solvents, defoamers, viscosity modifiers, other water-soluble polymers and mixtures thereof.