JPS5815580A - Surface protecting film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface protection film for plate materials such as steel plates and decorative plates. Plate materials such as steel plates and decorative laminates have a wide range of uses, including furniture and electrical appliances, but they are often laminated with a surface protection film for purposes such as surface protection and rust prevention during distribution and processing. Since the surface protection film is usually used after being peeled off from the plate material in the final product, (1) it has appropriate adhesive strength to the plate material, does not peel off during secondary processing such as distribution, embossing, bending, etc., and is easy to use after use. Things that can be peeled off. 1(2) No contamination to the plate material.

(3) Transparency - The surface of the plate material can be seen through.

(4) Appropriate weather resistance and little deterioration due to ultraviolet rays, heat, etc.

Conventionally, such protective films were manufactured by coating polyethylene, polyvinyl chloride, etc. films with acrylic or rubber adhesives, etc. As mentioned above, the circulation film is usually used after being peeled off in the final product, so the adhesive strength when pasting it to the surface of the board must not be too high.
A range of about 9/inch to several hundred 9/inch is considered appropriate. Although it cannot be said that sufficient theoretical analysis regarding adhesive force has been carried out at present, the adhesive force of an adhesive to an adherend is roughly determined by the wetting of the adherend, that is, the anchoring force of the adhesive, and the adhesive's anchoring force. It can be said that it is formed due to the cohesive force that it has. On the other hand, the desired adhesive strength of the surface-adhesive film is said to be relatively weak as described above, but this part has no choice but to weaken the anchoring force or cohesive force of the adhesive σ).

In addition, the purpose of the surface protection film is to protect the surface of the plate material to which it is adhered, and as mentioned above, it must not contaminate the surface of the plate material.However, in order to adjust the adhesive strength, the cohesive force of the adhesive If the adhesive is weakened, the cohesive force of the adhesive will be weak during peeling, resulting in cohesive failure of the adhesive itself (θ) or bleeding of additives such as plasticizers. There is a problem in that the anchoring force to the adherend is extremely reduced, and effective adhesive force cannot be obtained, or the adhesive force to the adherend is too large, which significantly impairs workability during peeling. The adhesive used in the surface protection film needs to have a suitable anchoring force to the adherend and a cohesive force with a greater peeling force.

The present invention was devised to solve the above problems, and aims to maintain appropriate strength by weakening the adhesive force to the adherend while maintaining the large cohesive force of the adhesive. Base material layer/
A surface protection film consisting of two or more layers of an adhesive layer or a back-treated base material layer/adhesive layer, and in which an inorganic filler with a particle size of 5 μ to 301 t is added to the adhesive layer in an amount of 05 to 20% by weight. Ru.

Since the present invention is made by adding an inorganic filler to the adhesive layer,
Fine irregularities are formed on the surface of the adhesive to reduce the contact area between the adhesive and the adherend, thereby adjusting the adhesive force to the adherend while maintaining the cohesive force of the adhesive.

To explain the present invention in more detail, the base material layer used is, for example, a film of polyethylene, polypropylene, polyvinyl chloride, etc., and a film having a thickness of about 60 to 200 μm is usually used, but of course it is difficult to form a film. If possible, it is not limited to these. Protective films are made by applying adhesive to such a base material, and usually without using release paper, etc.
It is often rolled up as it is, and when pasting it on a board material to be adhered to, the rolled version is unwound and used, but a blocking phenomenon occurs in which the adhesive and the base material layer adhere, and when unrolled, Since this may reduce workability, back surface treatment may be performed. Back treatment is a process that reduces the anchoring force of the adhesive on the surface of the base material (the side that is not coated with adhesive), weakens the adhesive strength, and improves unwinding and workability. silicone derivatives,
A treatment effect can be obtained by applying a treatment agent such as a long-chain alkyl compound or perfluoroalkyl compound, or by incorporating an organic lubricant such as fatty acid amide or wax, or an inorganic filler as described below.

Furthermore, the adhesive used is rubber or elastomer such as natural rubber, isogrene rubber, styrene butadiene rubber, styrene block copolymer rubber (SIS, 5BS), xfv propylene rubber, ethylene vinyl acetate copolymer resin, rosin, terpene, etc. Adhesive resin made by blending a tackifier such as resin, petroleum resin, coumaron indene resin, or adhesive resin such as acrylic adhesive, Merck (talc) silica, silicon oxide, kaolin (pottery clay), aluminum oxide. , zinc oxide, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, and other inorganic fillers. This inorganic filler is blended into the adhesive and forms fine irregularities on the surface of the adhesive, thereby reducing the area of the bonding surface with the adherend, thereby maintaining the cohesive force of the adhesive. It adjusts the adhesive force to
Powdered additives can be used within the range of 0.1 to 20% by weight, but inorganic additives like this can be added in large amounts (as this may reduce the original transparency of the resin). ,
Talc should preferably be used in an amount of 15% by weight or less, and among the inorganic fillers, talc has the best effect of adjusting the adhesive strength of the adhesive, which is the gist of the present invention. Incorporation of such an inorganic filler into the pressure-sensitive adhesive is achieved by means such as a hot melt mixing method using an extruder, a Banbury mixer with 13 rolls, a kneader, etc., a melt mixing method using a ball mill attritor, a sand mill, etc.

The adhesive in the present invention is applied to the substrate by solution coating such as gravure coating or roll coating, or by hot melt coating such as true melt coating or extrusion coating, but it is possible to apply the adhesive to the substrate by using a coextrusion method. ,
It is also possible to simultaneously extrude six or more layers of base material layer/adhesive layer or back treatment layer/base material layer/adhesive layer to form a film = 6 - The surface protection film produced in this way is The adhesive strength to the adherend plate material is adjusted without reducing the cohesive force of the adhesive, and it can be easily peeled off after use as a protective film, but does not leave any adhesive residue on the adherend. This makes it possible to prevent surface contamination caused by

Examples according to the present invention will be described below.

Example-1 (1) Adhesive layer blending ratio (heavy weight 1 adhesive formulation (weight ratio)) (2) Base material layer low density polyethylene (Milanon 12; Mitsui Polychemical ■) (3) Back treatment layer low density polyethylene ( Milanon 12; Mitsui Polychemical ■) Talc (SWA
(Average particle size 20 μ); Asahi Flour ■) (1) to (3) above
The following resin formulation was used. For the pressure-sensitive adhesive layer (1), A and B were added to the resin formulations ① to ②.

Next, using a coextrusion device, a processing temperature of 200°C (1) was used to form an adhesive layer of 20μ, a base material layer of 30μ, and a back treatment layer of 10μ.
The 3-layer molten film of μ was extruded onto a cooling roll to obtain a 6-layer film. The obtained film was passed between rubber rolls on an aluminum plate having a thickness of 05w++ which had been washed with trichlene, and was attached to the aluminum plate, and the peel strength was measured using Tensilon K (manufactured by Toyo Baldwin ■). (Table-1) Table-1 Example-2 5 parts by weight of Merck as in Example-1 was added to 100 parts of acrylic pressure-sensitive adhesive (BPS3841; ethyl acetate bath solution of 20%; manufactured by Toyo Ink Manufacturing Co., Ltd.). Then, mixing and dispersion was carried out for 24 hours using a ball mill (referred to as adhesive ①). This solution was subjected to corona discharge on one side in advance using a gravure plate with a plate depth of ioμ, and 10% polyisocyanate (Japan Polyurethane ■; Coronate R) was applied to the corona-treated side.
A 60μ low density polyethylene film coated with an ethyl acetate solution was coated. As a comparative example, low-density polyethylene was coated with an adhesive to which no talc was added (referred to as adhesive ①) using the same procedure as above. Further, the obtained adhesive-coated film was attached to an aluminum plate according to the procedure shown in Example 1, and its peel strength was measured (Table 2).

Table-2 patent applicant

Claims (1)

[Claims] (1) Consists of two or more layers: base material layer/adhesive layer, or back-treated base material layer/adhesive layer, and the adhesive layer has a particle size of 5 μm.
A surface protection film containing an inorganic filler with a thickness of 05 to 20 μm.