JPS59179674A - Adhesive polyolefin film - Google Patents

Abstract

PURPOSE:To provide the titled adhesive film well suited for protection of the surface of metallic plate, etc., by undercoating the surface of polyolefin film with a particular coupling agent and then forming an acrylic adhesive layer internally crosslinked by irradiation with UV light, etc. CONSTITUTION:A titanate coupling agent having carbon-carbon double bonds of e.g., formula I or II (wherein R1, R3, R4 are each alkyl; R2 is alkylene; x is 1-2; m is 0-2) is applied as an undercoat onto the surface of polyolefin film (e.g., polyethylene). Then, an acrylic adhesive layer internally crosslinked by irradiation with UV light or electron beams is formed thereon to yield the intended polyolefin adhesive film. This increases adhesion between the base film and the adhesive layer, and therefore no adhesive layer remains on the surface of an adhered when bonding said adhesive film to metal plate, etc. for the surface protection and peeling it after a prescribed period.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyolefin adhesive film having properties suitable for protecting the surfaces of metal plates, decorative plates, glass plates, etc.

This type of adhesive film has difficulty in adhesion with the adhesive layer, that is, anchoring force, because the polyolefin film that is the support is chemically inert. If it is peeled off after a predetermined period of time, there is a drawback that the adhesive will be transferred to the metal plate side.

For this reason, conventional surface treatment using a chromic acid-sulfuric acid mixture,
Means for activating the film surface by oxidation treatment such as flame treatment and corona discharge treatment is employed. However, with these methods, there are various problems such as insufficient treatment depending on the type of polyolefin film and the treatment effect decreasing as time passes after treatment.
The current situation is not completely satisfactory.

On the other hand, it is also known that the polyolefin film of the support is composed of a copolymer of ethylene monomer and a polar polymer such as vinyl acetate or acrylic acid ester to activate the surface. However, even with such means, sufficient adhesive force (anchoring force) has not been achieved at present.

As a result of extensive research in light of the above circumstances, the inventors developed an acrylic adhesive layer that is internally crosslinked by irradiation with ultraviolet rays or electron beams as an adhesive layer formed on a polyolefin film, and The surface of the film forming the adhesive layer is coated with a titanate coupling agent having a double bond, and the adhesive layer is internally crosslinked by irradiation with ultraviolet rays or electron beams, thereby forming a bond between the support film and the adhesive layer. It was discovered that the adhesion force (anchoring force) with

That is, the present invention provides a polyolefin adhesive film in which an acrylic adhesive layer that is internally crosslinked by irradiation with ultraviolet rays or electron beams is formed on the surface of a polyolefin film that is undercoated with a titanate coupling agent having double bonds. It depends.

According to the adhesive film having the structure mentioned above, the adhesive force (anchoring force) between the support film and the adhesive layer is very good, so it can be used for adhering to an adherend such as a metal plate for surface protection. When the adhesive layer is peeled off after a predetermined period of time has elapsed, the phenomenon that the adhesive layer is transferred and remains on the adherend side almost completely disappears. The reason for this is not clear, but the titanate coupling agent exhibits affinity for the polyolefin support, and when the adhesive layer is internally crosslinked by ultraviolet rays or electron beams, the titanate coupling agent It is presumed that the double bonds are also simultaneously activated by ultraviolet rays or electron beams to cause a crosslinking reaction with the constituent components of the adhesive layer, thereby greatly improving the adhesive strength between the support film and the adhesive layer. Ru.

Polyolefin films used in this invention include polyethylene, polypropylene, ethylene-α-olefin copolymers, etc., as well as copolymers of ethylene and acetic acid, hininopeacrylic acid, maleic anhydride, acrylic esters, etc. ) or a mixture of these polymers.

Furthermore, various titanate coupling agents having a double bond can be used, and typical examples include those of general formulas (I) and (If) i.

[(1) above, in formula (1), R1, 几3. Meat represents an alkyl group, R2 represents an alkylene group, X represents 1 or 2, and m represents 0 or 2. ] The titanate compound shown by these is mentioned.

Such a titanate coupling agent is applied to the surface of a polyolefin film as a solution dissolved in a solvent with toluenna and dried to form an undercoat. The amount of the titanate coupling agent to be used is preferably in a range where the undercoat thickness is 0.05 to 0.5μ2 to the polyolefin film, and if it is too small, the effect will not be sufficiently expressed.
On the other hand, if the amount is too high, the crosslinking reaction will proceed excessively, making the adhesive layer hard and causing problems in use.

Acrylic adhesives that are internally crosslinked by irradiation with ultraviolet rays or electron beams are photosensitized when irradiating ultraviolet rays on copolymers of acrylic monomers and vinyl monomers that can be copolymerized with the acrylic monomers. A crosslinkable monomer or a crosslinkable oligomer may be used in addition to the agent, and in the case of performing electron beam irradiation, a crosslinkable monomer or a crosslinkable oligomer may be added as necessary.

Examples of the photosensitizer include benzoin, benzoin compounds such as benzoin methyl ether and hendiine ethyl ether, carbonyl compounds such as methylanthraquinone, acetophenone and benzophenone, sulfur compounds such as diphenyl disulfide and dithiocarhame-1, and α-chloro Examples include naphthalene compounds such as methylnaphthalene, anthracene, and metal salt compounds such as iron chloride.

Such a photosensitizer contains 0.01 to 10 MM parts, preferably O1I to 10 MM parts, based on 100 weight m of the acrylic copolymer constituting the adhesive layer to be irradiated with ultraviolet rays.
It is sufficient to add about 5 parts by weight.

The above crosslinking monomers include ethylene glycol di(meth)acrylate and triethylene glycol di(meth)acrylate.
Polyethylene glycol di(meth) such as acrylate
Examples include acrylate compounds and triacrylate compounds such as trimethylolpropane trimethacrylate, and examples of crosslinkable oligomers include acrylic oligomers having 2 to 5 acryloyl groups to methacryloyl groups. In the above, (meth)acrylate is used to describe both acrylate and methacrylate-1 for convenience.

Such crosslinkable monomers and crosslinkable oligomers are added and blended as necessary to any adhesive layer to which ultraviolet ray irradiation and electron beam irradiation are applied. It is desirable that the amount of the crosslinkable monomer be 10 parts by weight or less, and the amount of the crosslinkable oligomer be 50 parts by weight or less.

In this invention, the ultraviolet rays used to internally crosslink the adhesive layer have a wavelength range of about 180 to 46 On772, and suitable irradiation sources include mercury arc,
Examples include low-pressure, medium-pressure, high-pressure, or ultra-high-pressure mercury lamps.

Further, the electron beam is 0.1 to 100 Mra, preferably 0
．． It is sufficient to irradiate at about 5 to 50 Mrad, usually for about 01 to 30 seconds.

In addition, in this invention, various commonly used additives such as fillers, colorants, and anti-aging agents may be appropriately added to the polyolefin film of the support and the adhesive layer depending on the purpose. can.

Hereinafter, this invention will be specifically illustrated based on Examples. In addition, in the following, all parts indicate parts by weight.

Example 1 Using a low density polyethylene resin with a melt intex of 3.7 and a density of 0.928, a thickness of 6011772 was produced using an extruder.
A polyethylene film was produced. A 10% by weight toluene solution of tetra(2,2-sialyloxymethyl-1-butyl)his(sheetritesyl)phosphite titanate was applied onto the film, and the titanate coupling agent was added to the polyethylene film at a concentration of 0.0%. An undercoat was applied to the film to a thickness of 1 μm, and the film was dried at 90° C. for 1 minute.

Next, an adhesive composition solution consisting of the following components was prepared and applied to the surface of the undercoated polyethylene film so that the thickness after drying was 10 μm, and dried at 90° C. for 2 minutes.

Butyl acrylate-acrylonitrile-acrylic acid copolymer rubber (M ratio 80:20:5, molecular weight 600,000)
...100 parts benzophenone
...0.5 part toluene
...400 parts, then 100 parts of the obtained film
An adhesive film was obtained by irradiating the adhesive layer with a W high-pressure mercury lamp at a height of 15 cm from the surface of the adhesive layer for 1 minute.

Example 2 Instead of the titanate-based lumping agent of Example 1,
Isobrobyl isostearoyldiacryl titanium I.
An adhesive film was obtained in the same manner as in Example 1 except that .

Example 3 An adhesive film was obtained in the same manner as in Example 1 except that 1 part of triethylene glycol diacrylate was added to the adhesive composition of Example 1.

Example 4 An adhesive film was obtained in the same manner as in Example 1, except that 10 parts of Aronix 6400X (trade name, manufactured by Toagosei Co., Ltd.) was added as a crosslinkable olicomer to the adhesive composition of Example 1.

Example 5 An adhesive film was obtained in the same manner as in Example 1, except that the adhesive composition of Example 1 without benzophenone was used, and instead of ultraviolet irradiation, electron beam irradiation was performed at a dose of 5 Mrad.

Example 6 An adhesive film was obtained in the same manner as in Example 5, except that 1-1 parts of trimethylolpropane triacrylate was added as a crosslinkable monomer to the adhesive composition of Example 5.

Example 7 Instead of the low density polyethylene resin in Example 1,
An adhesive film was obtained in the same manner as in Example 1, except that the support film was formed using an ethylene-acrylic acid copolymer having Melt Intex 5.5, density 0.9B2, and acrylic acid content of 8% by weight. Ta.

Example 8 Instead of the low density polyethylene resin in Example 1,
An adhesive film was obtained in the same manner as in Example 1, except that the support film was formed using an ethylene-vinyl acetate copolymer having a melt index of 3.5, a density of 0.980, and a vinyl acetate content of 14% by weight. child.

Reference Example 1 An adhesive film was obtained in the same manner as in Example 1, except that the adhesive composition of Example 1 without benzophenone was used and the adhesive composition was bonded by irradiation with ultraviolet rays.

Reference Example 2 An adhesive film was obtained in the same manner as in Example 1, except that the undercoating of Example 1 was not applied.

Each adhesive film obtained in the above Examples and Reference Examples was tested for adhesive strength and adhesive residue.

The results are shown in the table below. The test method is as follows.

Adhesive Strength> The force required for peeling when the interface between the support film and the adhesive layer was forced to peel was measured.

<Adhesive Remaining Resistance> Adhesive film is pasted on 0.6 vtm thick B, A, finished stainless steel plates (SUS304), drawing processing is performed, and after processing, the film is peeled off and the adhesive layer is transferred to the stainless steel plate. It was determined visually whether or not the test was completed.

As is clear from the above table, the polyolefin adhesive film according to the present invention is an adhesive film without an undercoat of a titanate coupling agent having a double bond, and an adhesive film in which the adhesive layer is exposed to ultraviolet rays or electron beams. Compared to adhesive films made of non-crosslinked materials, the adhesive force between the support film and the adhesive layer is stronger, and when peeled off after the required period of time or required processing while adhering to the adherend, it will not adhere to the adherend. Since there is no transfer residue of the adhesive layer, it can be seen that it is most suitable for protecting the surfaces of metal plates, decorative plates, glass plates, etc.

Patent Applicant Nitto Electric Industry Co., Ltd. Agent Patent Attorney Moto Kunio Negi, PA 2- Procedural Amendment June 1, 1980 Director-General of the Japan Patent Office 1, Indication of Case Patent Application No. 58-57111 2, Invention Name: Polyolefin adhesive film 3, Relationship with the person making the amendment Patent applicant: 4, Agent: 6, “Claims” of the specification to be amended, [Detailed description of the invention, 7 of the amendment] Content A: Specification 11) We will make one correction to the scope of patent claims as shown in the attached sheet.

(2) 5th line from the bottom of the first page, 8th line from the bottom of the second page,
Ki → Tribute Concubine Scale and page 3, line 10; We have corrected the words ``anchor-throwing power'' to read ``one anchor-throwing force,'' respectively.

(3) Line 3 from the bottom of page 2 N1 Line 4 of page 3, Line 2 from the bottom of page 3, Line 11 of page 4, and Line 1 of page 13
Line: "Double bond" is replaced with "carbon-carbon double bond"
I would like to correct you.

Attachment Amended Claims ``(1) An acrylic adhesive that is internally crosslinked by irradiation with ultraviolet rays or electron beams on the surface of a polyolefin film that is undercoated with a titanate coupling agent having carbon-carbon double bonds. A polyolefin adhesive film formed of layers.'' Patent applicant: Nitto Electric Industry Co., Ltd.

Claims (1)

[Claims] (1) A polyolefin adhesive film in which an acrylic adhesive layer internally crosslinked by irradiation with ultraviolet rays or electron beams is formed on the surface of a polyolefin film that is undercoated with a titanate coupling agent having double bonds.