JP2001279203A - Adhesive tape for surface protection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive tape for surface protection having transparency and excellent weather resistance usable even under a condition of high ultraviolet light intensity such as outdoors. SOLUTION: This adhesive sheet for surface protection is characterized by forming an adhesive layer composed of an acrylic copolymer or a hydrogenated substance of a styrene-diene-based hydrocarbon copolymer on one side of a polyolefin-based substrate having transparency and <=10% ultraviolet transmission amount in a range of 190-370 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet for protecting a surface which is excellent in weather resistance and is mainly used for a stainless plate, an aluminum plate, a glass plate, a painted plate and the like.

[0002]

2. Description of the Related Art Conventionally, stainless steel plates, aluminum plates,
As a substrate of the surface protecting adhesive sheet used for transporting, curing, and preventing scratches during construction of glass plates, and painted plates, etc., polyolefin resins such as polyethylene and polypropylene are used, As the pressure-sensitive adhesive laminated on one surface of the support, natural rubber-based, synthetic rubber-based, and acrylic-based resins have been used.

[0003] However, since such a base material and an adhesive are deteriorated in a short time due to sunlight, mainly ultraviolet rays, when the protective adhesive sheet is peeled off, the base material and the adhesive layer are broken or the adhesive is removed. Remains on the adherend. In order to solve the above problems, a method of completely absorbing and shielding ultraviolet rays by including a pigment in a substrate or an adhesive layer (Japanese Patent Laid-Open No. 5-148460); A method of imparting weather resistance by adding an agent (Japanese Patent Application Laid-Open No. 8-325537) and the like have been studied.

[0004] However, the method of coloring the substrate is limited in its use because it is not possible to identify and determine the contents such as the hue of the adherend. In addition, in the method of adding an ultraviolet absorber to a base material and an adhesive, generally, the compatibility between the adhesive resin and the ultraviolet absorber is not good. The problem of contamination arises.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art and to provide a transparent and weather-resistant surface protective pressure-sensitive adhesive sheet which can be used even under conditions of high ultraviolet intensity, such as outdoors. Is to provide.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have completed the following transparent weather-resistant surface protective film. The present invention has transparency, and the ultraviolet ray transmission amount is 190 to 370 nm.
The pressure-sensitive adhesive layer comprising a hydrogenated product of an acrylic copolymer or a styrene-diene-based hydrocarbon copolymer was formed on one surface of a polyolefin-based substrate having a content of 10% or less in the range of It is a pressure-sensitive adhesive sheet for surface protection.

The polyolefin-based substrate is not particularly limited as long as it is a polyolefin film (sheet) having transparency and flexibility containing polyethylene, polypropylene or a mixture thereof as a main component.

As the above polyethylene, high density polyethylene (HDPE), medium density polyethylene (MDP)
E), low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and the like,
Long-chain olefin monomers such as 1-butene and 1-pentene may be copolymerized.

Examples of the polypropylene include random polypropylene, homopropylene, high crystallinity polypropylene, block polypropylene and the like.

The above-mentioned polyolefin-based substrate may contain, if necessary, various conventionally known additives such as an antioxidant, an antioxidant, a light stabilizer and the like within a range not to impair the object of the present invention. May be added.

The polyolefin-based substrate used in the present invention has an ultraviolet transmission amount of 10 to 190 nm in the range of 10 to 370 nm.
% Or less. By setting the amount of ultraviolet transmission to the above value,
It is possible to effectively shield ultraviolet rays from being applied to the adhesive located below the base material layer.

As a means for suppressing the amount of transmitted ultraviolet light within the specific range of the present invention, there is a method of including an ultraviolet absorbent. Such materials include salicylic acid derivatives, benzophenones, triazoles, triazines, hindered amines and the like. Regarding the type and amount of addition, the amount of transmission of ultraviolet light of the support film,
There is no particular limitation as long as it can be reduced to 10% or less in the wavelength range of 190 to 370 nm.

As the triazine-based ultraviolet absorber, Tinuvin 1577FF (trade name; manufactured by Ciba Geigy) is commercially available and is preferably used in the present invention.

The thickness of the substrate can be appropriately selected depending on the purpose, but is usually preferably from 30 to 200 μm, more preferably from 40 to 100 μm.

In the present invention, an acrylic copolymer is used as the pressure-sensitive adhesive layer. Acrylic copolymer is a compound having 1 to 1 carbon atoms.
Using a (meth) acrylic acid alkyl ester having an alkyl group of 14 as a main component, another vinyl monomer is used to adjust the glass transition temperature and polarity of the obtained acrylic copolymer or to introduce a functional group. It is obtained by copolymerization.

Examples of the alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl acrylate, n-propyl (meth) acrylate, and (meth) acrylate. Acrylic acid isopropyl ester, (meth) acrylic acid n-butyl ester, (meth) acrylic acid sec-
Butyl ester, t-butyl (meth) acrylate, cyclohexyl methacrylate, n-octyl (meth) acrylate, isooctyl acrylate, 2-ethylhexyl (meth) acrylate, isononyl acrylate, Lauryl (meth) acrylate and the like can be mentioned.

The alkyl (meth) acrylate may be used alone or in combination of two or more. As the copolymerizable vinyl monomer, α-
Styrene monomers represented by methylstyrene, vinyltoluene, styrene, etc .; vinylether monomers represented by methylvinylether, ethylvinylether, isobutylvinylether, etc .; fumaric acid, monoalkyl esters or dialkyl esters of fumaric acid Maleic acid, monoalkyl or dialkyl esters of maleic acid; itaconic acid, monoalkyl or dialkyl esters of itaconic acid; (meth) acrylonitrile, butadiene, isoprene, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl ketone, vinyl Examples include pyrrolidone, vinylpyridine, (meth) acrylamide, vinylcarbazole and the like.

The weight average molecular weight of the acrylic copolymer is preferably from 10,000 to 4,000,000, and more preferably from 200,000 to 2,000,000. If it is less than 10,000,
In some cases, the properties as an adhesive cannot be exhibited,
If it exceeds 10,000, the viscosity at the time of production increases, which is not preferable in terms of productivity.

The above acrylic copolymer can be obtained by any method such as solution polymerization, emulsion polymerization, bulk polymerization and the like. Furthermore, a non-solvent liquid mixture comprising a monomer and a photopolymerization initiator can be photopolymerized by irradiating it with ultraviolet light in an inert gas such as nitrogen.

In the present invention, as another pressure-sensitive adhesive layer,
A hydrogenated styrene-diene hydrocarbon copolymer is used. A hydrogenated product of an ABA block copolymer comprising a styrene polymer block (A) and a butadiene polymer block or an isoprene polymer block (B), or a styrene polymer block (A) and styrene It is a hydrogenated product of an AC block copolymer with a butadiene or isoprene random copolymer block (C). Specifically, as the hydrogenated product of the former ABA block copolymer, a trade name of " Tuftec H105
2 "(manufactured by Asahi Kasei Corporation) is commercially available.

The weight average molecular weight of the hydrogenated styrene-diene copolymer is 50,000 to 4 in terms of polystyrene.
It is preferably from 100,000, more preferably from 80,000 to 200,000.
If the weight average molecular weight is less than 50,000, the cohesive strength of the pressure-sensitive adhesive is reduced, so that adhesive remains on the adherend at the time of re-peeling. If it exceeds 400,000, the adhesive strength is insufficient and the fluidity is poor.

The hydrogenated product of the styrene-diene-based hydrocarbon copolymer or the acrylic copolymer used in the pressure-sensitive adhesive layer of the present invention may, if necessary, be added to a conventional one as long as the object of the present invention is not impaired. Various known additives, for example, a crosslinking agent, a plasticizer, a softener, a filler, a stabilizer, an antioxidant, a pigment, a dye, and the like may be included.

The thickness of the pressure-sensitive adhesive layer can be appropriately selected depending on the purpose, but is usually 1 to 50 μm, preferably 5 to 30 μm.
μm. When the thickness is less than 1 μm, the tackiness decreases, and
If it exceeds μm, it becomes uneconomical.

The method for producing the protective pressure-sensitive adhesive sheet of the present invention can be provided by known means.
It is obtained by applying a pressure-sensitive adhesive solution on a substrate film by a roll coater and then drying in an oven.

[0025]

The pressure-sensitive adhesive sheet for surface protection using the substrate of the present invention can effectively prevent harmful ultraviolet rays from being applied to the pressure-sensitive adhesive layer, so that deterioration of the pressure-sensitive adhesive over time can be prevented. Therefore, the pressure-sensitive adhesive sheet for surface protection using the substrate of the present invention has good weather resistance and can be used even under conditions of high ultraviolet intensity such as outdoors. In addition, because of the transparency, the contents of the adherend can be identified.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. Example 1 A 2-liter separable flask equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet was charged with 420 g of butyl acrylate (BA) and acrylic acid (A).
Ac) 1 g, PMMA macromonomer (trade name "AA-
6 "; manufactured by Toa Gosei Co., Ltd.) and 450.91 g of toluene as a polymerization solvent. After the dissolved oxygen was removed by bubbling the monomer mixed solution with nitrogen gas for 20 minutes, the inside of the separable flask system was replaced with nitrogen gas, and the monomer mixture was stirred using a water bath while stirring at 100 rpm. The mixed solution was heated.

When the reflux liquid is confirmed in the cooling pipe, 1,1-di (t-hexylperoxy) as a polymerization initiator is used.
0.30 g of -3,3,5-trimethylcyclohexane (trade name "Perhexa TMH"; manufactured by NOF CORPORATION) is about 1 g
Was dissolved and added to ethyl acetate to initiate boiling point polymerization. After 1 hour, the perhexa TMH 0.60
g was dissolved in about 1 g of ethyl acetate and charged. After 2, 3 and 4 hours from the initiation of polymerization, di (3,5,5-trimethylhexanoyl) peroxide (trade name “Perloyl 35”)
5 "; manufactured by NOF CORPORATION] 0.60 g, 1.20 g and 1.
80 g was dissolved in about 1 g of ethyl acetate and charged. The target acrylic copolymer was obtained by conducting the boiling point polymerization for 8 hours.

(Preparation of coextruded pressure-sensitive adhesive sheet) The acrylic copolymer was taken out from the acrylic copolymer solution by removing toluene by a conventional method. The acrylic copolymer obtained as the pressure-sensitive adhesive layer was used as a base material layer in 100 parts of low-density polyethylene (trade name “Mirason 12”; manufactured by Mitsui Chemicals, Inc.) and an ultraviolet absorber (trade name [Tinuvin 15]
77FF]; Ciba-Geigy)
By co-extrusion, a pressure-sensitive adhesive sheet for surface protection having a pressure-sensitive adhesive layer of 10 μm and a base material layer of 50 μm was obtained.

Example 2 The procedure of Example 1 was repeated, except that the pressure-sensitive adhesive layer was changed to a hydrogenated product of styrene / butadiene / block copolymer (trade name “TUFTEC H1052”; manufactured by Asahi Kasei Corporation). Thus, an adhesive sheet for surface protection was obtained.

Comparative Example 1 An adhesive sheet was obtained in the same manner as in Example 1 except that low-density polyethylene, trade name "Mirason 12" (manufactured by Mitsui Chemicals, Inc.) was used alone as the base material layer. Was.

(Measurement of Adhesive Strength)
According to Z0237, it was stuck to a SUS304 plate with a width of 25 mm, left at 23 ° C. for 20 minutes, and peeled in a 180 ° direction at a pulling speed of 300 mm / min.
The peel strength was measured.

(Evaluation of UV Transmission Amount of Substrate) The UV transmission in the range of 190 to 370 μm was measured with an ultraviolet / visible spectrophotometer. The results are shown in Table 1.

(Evaluation of weather resistance and light resistance)
In accordance with JIS B 7753, light was irradiated for 500 hours with a sunshine weather meter (WEL-SUN-HC, manufactured by Suga Test Instruments Co., Ltd.), and a pulling speed of 3 in the 180 ° direction was measured.
Peeling was performed under the condition of 00 mm / min, and the peeling force was measured.
This peeling force was used as a guideline for evaluating weather resistance and light resistance. The results are shown in Table 1.

[0034]

[Table 1]

As is clear from Table 1, the surface protecting pressure-sensitive adhesive sheet of the present invention has a harmful effect on the pressure-sensitive adhesive layer by adding an ultraviolet absorber to the base layer so as to suppress the transmitted dose in a specific wavelength region. UV rays can be effectively shielded, and the deterioration of the adhesive over time can be prevented.

[0036]

As described above, the pressure-sensitive adhesive sheet for surface protection of the present invention can effectively shield harmful ultraviolet rays to the pressure-sensitive adhesive layer by setting the amount of ultraviolet rays absorbed by the substrate layer to a specific range. The deterioration of the adhesive over time can be prevented. The substrate layer of the pressure-sensitive adhesive sheet for surface protection of the present invention is transparent because substantially no pigment or the like is added. Since it has transparency, the adherend can be identified, and can be used under conditions of high ultraviolet intensity, such as outdoors.

Continued on the front page F-term (reference) 4F100 AK03A AK06 AK12B AK12J AK25 AK25B AK25J AK28B AK28J AK62A AK66A AK73 AK73B AL01 AL01B AL02 AR00A BA02 CA07 CA16B EH20 GB90 JD09 JD09A04 J01A01A04 J14A01 J04A04

Claims (1)

[Claims] 1. It has transparency, and the amount of transmitted ultraviolet light is
In the range of 190 to 370 nm, an acrylic copolymer,
Or a pressure-sensitive adhesive sheet for surface protection, wherein a pressure-sensitive adhesive layer comprising a hydrogenated product of a styrene-diene-based hydrocarbon copolymer is formed.