JPH0129234B2 - - Google Patents

Description

[Detailed description of the invention]

This invention includes stainless steel plates, aluminum plates,
To prevent the surface from being damaged or contaminated when processing a metal plate-shaped article such as a copper plate, especially during heat processing, and to prevent the surface from being easily peeled off after processing without contaminating the surface. This article relates to a surface protection adhesive that can be used. In general, surface protective adhesives are used when storing various items.
It is temporarily attached to the surface of the article to prevent damage and contamination of the surface of the article during transportation, processing, etc., and is made to be easily peeled off after the purpose is achieved. However, when performing processing such as partially painting a metal plate, applying adhesives, applying various resins, and applying various types of primer, it is often necessary to heat the metal plate to a temperature of 150°C or higher. In conventional surface protection adhesives, heating significantly reduces the strength of the base film of the adhesive and significantly increases the adhesive strength between the metal plate and the adhesive. There were problems such as it being difficult to peel off from the plate, and contamination or residual adhesive remaining on the surface of the metal plate after peeling. As a result of various studies aimed at obtaining a surface protection adhesive with excellent heat resistance that does not have the above-mentioned problems, the inventors found that a predetermined amount of hindered phenol antioxidant was added to the adhesive used for the surface protection adhesive. The present inventors have discovered that the adhesive body can be satisfactorily used in applications requiring a high-temperature heating process by incorporating the above-mentioned adhesive. That is, the present invention has a configuration in which an adhesive layer is formed by applying and heating an adhesive composition containing an acrylic copolymer as a main component and a crosslinking agent to a polyolefin film, and adding a binder to the adhesive composition. The present invention relates to a surface protection adhesive having excellent heat resistance, which contains a dophenol-based antioxidant in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the acrylic copolymer. A polyolefin film is used as the base material for the surface protection adhesive of the present invention, and in the case of polyethylene film, it is preferable to use a low-density polyethylene film, which has excellent heat resistance and mechanical properties. The acrylic copolymer that is the main component of the adhesive composition in this invention includes acrylic monomers such as 2-hydroxyethyl acrylate and (meth)acrylic acid having polar groups such as alcoholic hydroxyl groups and carboxyl groups. copolymer with an acrylic acid alkyl ester having a carbon number of 10 or less, such as ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, or a copolymer of the acrylic monomer and the acrylic alkyl ester with various copolymers. A methacrylic acid ester or a copolymer with a vinyl monomer such as acrylonitrile, vinyl acetate, or vinyl ether is used. The copolymerization ratio of the acrylic monomer having a polar group in the acrylic copolymer is preferably 0.2 to 20% by weight. Further, as the crosslinking agent contained in the pressure-sensitive adhesive composition, trimethylolpropane adduct of tolylene diisocyanate, ethylene diisocyanate,
Polyfunctional isocyanates such as 1,4-butane diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, or initial condensates of alkyl etherified methylolmelamine, alkyl ethers initial condensate of methylolurea,
Examples include initial condensates of alkyl etherified methylolmelamine urea. The amount of the crosslinking agent used is usually 1 to 20 parts by weight per 100 parts by weight of the acrylic copolymer. If the amount used is too small, the acrylic If the crosslinking of the copolymer is insufficient, the desired heat resistance cannot be obtained in the surface protection adhesive, and if the amount is too high, the adhesiveness of the adhesive layer decreases, resulting in poor adhesive strength, which is not preferable. It is important that the adhesive composition in this invention contains a hindered phenol antioxidant. The above antioxidant is generally used as an antioxidant for polymer films, and for example, 1.
3,5-trimethyl-2,4,6-tris (3,
5-di-tert-butyl-4-hydroxybenzyl)benzene, pentaerythrityl-tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n -octylthio)-6-(4-hydroxy-
3,5-di-tert-butylanilino)-1,3.
5-triazine, octadecyl-3-(3,5-
di-tert-butyl-4-hydroxyphenyl) propionate, N・N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxycinamamide), 2,2-thiodiethylbis[3-
Examples include (3,5-di-tert-butyl-4-hydroxyphenyl)propionate. The amount of the hindered phenol antioxidant used is 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the acrylic copolymer. If the amount used is less than 0.05 part by weight, the desired heat resistance will not be obtained for the surface protection adhesive, and the
If it exceeds 1 part by weight, the adhesive properties of the pressure-sensitive adhesive layer will deteriorate, which is not preferable. In addition to the above-mentioned components, the adhesive composition may optionally contain polyterpene, rosin and its derivatives, tackifier resin such as chromanindene resin, petroleum hydrocarbon resin, monomer and Phosphate esters such as di(polyoxyethylene alkyl ether) phosphates, mono- and di(polyoxyethylene alkyl phenol) phosphates may be included. The amount of these tackifying resins used is usually 5 to 30 parts by weight per 100 parts by weight of the acrylic copolymer.
The amount of the phosphoric acid ester is preferably 0.05 to 5 parts by weight. The adhesive composition formulated as described above is usually dissolved in benzene, ethyl acetate, methyl ethyl ketone, etc., and applied to one side of a polyolefin film with a thickness of 20 to 200 μm to a thickness of 2 to 20 μm after drying.
Coat to a thickness of 20 μm, and apply at 50 to 120℃ to a thickness of 0.5 to 5.
The surface-protecting adhesive body of the present invention is obtained by heating for a minute to dry and crosslink. In the surface protection adhesive obtained in this way,
The heat resistance of the adhesive layer is improved by the effect of the hindered phenol antioxidant contained in the adhesive layer, and the initial adhesive strength is maintained even after heating, and the antioxidant is transferred to the polyolefin film. In order to prevent the film from deteriorating during heating, it can be easily peeled off from the adherend even after heating, and does not leave any residue or contaminate the surface of the adherend. Furthermore, no bleeding occurs, which occurs when the antioxidant is simply added to the base film. Therefore, the surface protection adhesive body is suitable for protecting the surface of a metal plate that requires a heating process. For example, when a stainless steel plate is roll-formed as a weather strip for an automobile and then partially undercoated and attached by hot extrusion of vinyl chloride resin, the surface protection adhesive of the present invention may be used to protect the surface of the stainless steel plate. When used, it is heated to around 150°C in the undercoating process, and heated to around 200°C in the resin application process, but after the process is finished, the adhesive can be easily removed from the stainless steel plate without contaminating it or leaving any glue residue. Can be peeled off. In addition, when applying melamine paint to parts of a stainless steel plate such as a calculator after forming it as a nameplate, heating at 150℃ for about 30 minutes is required.
In this case as well, the surface protection adhesive of the present invention can be suitably used. Next, examples of this invention will be described. Note that parts below mean parts by weight. Example 1 5 parts of trimethylolpropane adduct of tolylene diisocyanate was added to 100 parts of an acrylic copolymer obtained by copolymerizing 80 parts of 2-ethylhexyl acrylate, 20 parts of ethyl methacrylate, and 2 parts of acrylic acid. 1 part, 2 parts of butyl etherified melamine,
Mono and di(polyoxyethylene dodecyl phenol ether phosphate ester 1 part, xylene resin
20 parts, pentaerythrityl-tetrakis [3-(3.5-
0.5 part of di-tert-butyl-4-hydroxyphenyl)propionate was added and mixed and dissolved in toluene to prepare an adhesive composition solution. Thickness when corona discharge treatment is applied to one side of the solution
Apply it to the treated surface of a 60μm low-density polyethylene film so that the thickness after drying is 10μm,
A surface protective adhesive was obtained by heating at 85° C. for 2 minutes. Example 2 To 100 parts of an acrylic copolymer obtained by copolymerizing 80 parts of butyl acrylate, 20 parts of acrylonitrile, and 3 parts of 2-hydroxyethyl methacrylate, 4 parts of ethylene diisocyanate, mono- and Di(polyoxyethylene lauryl ether) phosphate ester 0.2 part, 2,4-bis(n
-octylthio)-6-(4-hydroxy-3,5
0.5 part of -di-tert-butylanilino)-1,3,5-triazine was added and mixed, and dissolved in a mixed solvent of toluene and ethyl acetate to obtain an adhesive composition solution. A surface protective adhesive body was obtained in the same manner as in Example 1 using the above solution. Comparative Example 1 A surface protection adhesive was obtained in the same manner as in Example 1 using the adhesive composition of Example 1 except that the hindered phenol antioxidant was removed. Comparative Example 2 A surface protection adhesive was obtained in the same manner as in Example 2 using the adhesive composition of Example 2 using a hindered phenol antioxidant. The surface protection adhesives obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were cut into 20 mm width samples and pasted on a BA finished stainless steel plate, and heat treated under the conditions shown in the table below. The 180 degree peel adhesive strength (g/20mm) was measured. In addition, the peeling speed is
300mm/min. The above measurement results are shown in the table below.

[Table] *1 Glue residue, *2 Surface contamination As is clear from the above measurement results, the surface protection adhesive of this invention containing a hindered phenol antioxidant in the adhesive layer is used to protect the surface of a metal plate. Then, even when the adhesive is heat-treated to around 200°C, the adhesive strength does not increase significantly and the initial adhesive strength is maintained, making it easy to peel and eliminating the need to leave residue or contaminate the metal plate surface. It can be seen that it is excellent for protecting the surface of metal plates that require a heating process.

Claims (1)

[Claims] 1 Consisting of a polyolefin film coated with an adhesive composition containing an acrylic copolymer as a main component and a crosslinking agent and heated to form an adhesive layer, the adhesive composition is coated with a hindered phenol antioxidant. agent to 100 parts by weight of the acrylic copolymer.
A surface protection adhesive having excellent heat resistance, characterized by containing 0.05 to 5 parts by weight.