JPH03236938A - Bonding method - Google Patents

Abstract

PURPOSE:To eliminate the possibility of generating whiting and foaming phenomena and retaining practical bonding strength by using a bonding agent composed of a specified solvent component blended with the specified ratio. CONSTITUTION:An acryl resin material as a material bonded on the surface of a base composed of a polycarbonate resin sheet on which an acryl film layer is provided. At the time of bonding, a bonding agent, composed of a mixed solvent comprising 100pts.wt. of 1,4 - dioxane and 5 - 15pts.wt. of 1,1,1 - trichloroethane, mixed with 25 - 45pts.wt. of 1,1 - dichloroethane is used. The bonding method is carried out by contact clamping the material to be bonded starting from one end to the other end gradually in a manner of being coated on the bonding face uniformly while injecting bonding agent into a contact clearance between the base and the material to be bonded, and then drying for a proper time to complete the bonding work.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for bonding an acrylic resin material as an adherend to the surface of a substrate made of a polycarbonate resin plate provided with an acrylic film layer on the surface.

Conventional Technologies and Problems Generally, when bonding different types of synthetic resin materials, especially non-crystalline synthetic resin materials, with a solvent-based adhesive, a solvent component that swells and softens the surface of each material is added to the bonding surface of the materials. It is well known that the following adhesives can be used. When adhering an acrylic resin material as an adherend to the surface of a polycarbonate resin plate, an adhesive containing dichloromethane, 12-dichloroethane, etc. alone or mixed with other solvent components has been conventionally used.

By the way, although polycarbonate resin has excellent transparency and high impact strength, it has the disadvantage that its surface easily deteriorates due to the influence of ultraviolet rays contained in sunlight, humidity, etc., so it is used for example in outdoor signboards and outdoor display devices. When used as a face plate for a product, etc., a substrate with an acrylic film layer provided on the surface for the purpose of preventing deterioration is used as a substrate, and then a transparent or colored transparent acrylic resin plate is coated via this film layer. Display materials cut out into characters or figures are glued together to form various types of face plates.

However, when adhering an acrylic resin material via an acrylic film to the surface of a polycarbonate resin plate with an acrylic film layer provided on the surface in this way, using the above-mentioned conventional adhesive is not practical. Although adhesive strength can be obtained, there is a problem in that whitening or foaming occurs at the adhesive interface. In particular, the whitening phenomenon tends to appear on the surface of the polycarbonate resin plate that comes into contact with the acrylic film. These phenomena not only significantly reduce the appearance quality of the product due to its intended use, but also, in the case of foam, it repeatedly expands and contracts with temperature changes during use, which causes cracks at the adhesive interface, resulting in display problems. There has been a problem in that parts swell and even peel, which has a significant negative effect on the display function of signboards and the like.

Of course, such problems can be solved to some extent by commonly known techniques, such as adjusting the amount of adhesive so that it is not too much, or pressing the bonded area more evenly with just the right amount of pressure. Although it is possible to solve the problem, there are problems in terms of workability, such as the fact that such work is actually quite difficult and requires skill.

This invention was made in light of the above points, and by using an adhesive containing a specific solvent component in a specific ratio, whitening and foaming phenomena do not occur at the adhesive interface. Moreover, the present invention provides an adhesion method that can maintain practical adhesion strength.

Means for solving the problem, that is, the present invention, provides the following steps when adhering an acrylic resin material as an adherend to the surface of a substrate made of a polycarbonate resin plate with an acrylic film layer provided on the surface.
100 parts by weight of 4-dioxane and 1. 1. 1-) The gist is a bonding method using an adhesive in which 25 to 45% by weight of 11-dichloroethane is mixed with a mixed solvent consisting of 5 to 15 parts by weight of dichloroethane.

Next, the component amounts of the adhesive used in this invention will be described. First, for a mixed solvent of 1.4-dioxane and 1°1.1-trichloroethane, 1°1.1 trichloroethane 5 to 1
It is 5 parts by weight. This limitation was made to 1.0 parts by weight per 100 parts by weight of 1,4-dioxane. 1. This is because if the amount of l-trichloroethane is less than 5 parts by weight or exceeds 15 parts by weight, foaming and whitening will occur at the adhesive interface. Also, 1,4-dioxane and 1. 1. 1-) Regarding the amount of 1,1-dichloroethane mixed with respect to the mixed solvent with dichloroethane, 1,1-dichloroethane is 25 to 45% by weight. The limitation in this case is also due to the fact that whitening and foaming occur at the adhesive interface when the content is less than 25% by weight or more than 45% by weight.

The acrylic film used in this invention is, for example, a polymethacrylic acid ester-based film, with 25 to 1
A thickness of 50 μm is used, preferably 40 μm.
The thickness ranges from ~100 μm. This film is usually laminated and imaged onto the surface of a polycarbonate resin when it is formed into a plate shape by extrusion molding or the like.

Effect of the Invention When using the method of the present invention, while injecting the adhesive into the contact gap between the substrate and the adherend, the adhesive is applied to one end of the adherend so that it is evenly applied to the adhesive interface. The bonding process is completed by sequentially applying contact pressure from one end to the other end and drying at the appropriate time.

At this time, the film on the surface of the substrate initially swells and softens due to the adhesive, and the surfaces of the substrate and adherend also swell and soften appropriately, and over time they bond together and solidify, developing adhesive strength. be. Therefore, the effect of the present invention is not fundamentally different from the bonding effect of conventionally known solvent bonding methods in that it swells and softens the surfaces of the base material and adherend. However, it is thought that it actually has the following unique effect.

That is, in this invention, the supplied adhesive is first absorbed into the acrylic film, causing it to swell and soften, and then reaches the surface of the polycarbonate resin plate, but the amount is not excessive on the surface. The surface is appropriately swollen and softened, and the surface of the acrylic resin material as the adhesive material is also moderately swollen and softened.
It is thought that it acts to prevent whitening and foaming phenomena at the adhesive interface. Furthermore, in conjunction with the fact that the dissolving action and wettability of each component of the adhesive are in proper harmony, adhesive strength can be maintained sufficiently for practical purposes.

In this invention, the components that have a dominant effect on swelling and softening are 11-dichloroethane for the substrate, and 1,1-dichloroethane and 1,4-dichloroethane for the adherend.
- Dioxane. And],, 1. ．． 1. −
1-lichloroethane contributes to wettability.

Effects of the Invention According to the adhesion method of the present invention, as will be clear from the examples described later, an acrylic film layer is provided on the surface of /S.
Adhesion work can be performed without causing any whitening or foaming phenomenon at the adhesion interface between the surface of the polycarbonate resin plate and the acrylic resin material, and moreover, the adhesion work can be performed over a wide area without difficulty.

Therefore, if the adhesion method of the present invention is applied to the production of, for example, the face plate of an outdoor signboard or outdoor display device, the substrate is a polycarbonate resin plate provided with an acrylic film layer on the surface, and the acrylic resin material is used as the adherend. , it is possible to manufacture a face plate without defects such as spots or bubbles due to whitening at the adhesive interface, and there is no risk of cracks at the adhesive interface or peeling of the adherend, and it is highly durable and can withstand long-term use. It becomes possible to manufacture signboards, display devices, etc.

Example Examples of the present invention will be described below in comparison with comparative examples.

First, as a substrate, a 50 μm thick acrylic film layer was heat-pressed and integrally provided on the surface.
mm polycarbonate resin plate (product name: Polyriki Ace, product number: ECKIo 0 L, manufactured by Tsutsunaka Plastic Industry Co., Ltd.) and a 2 mm to 3 m thick polycarbonate resin plate as an adherend.
m transparent acrylic resin plates (product name Sumipex E,
Product number EOOO5 (manufactured by Sumitomo Chemical Industries, Ltd.) was prepared.

On the other hand, as an adhesive, 1,4-dioxane, 1,
1. Each solvent component of 1-1-lichloroethane and 11-dichloroethane and other solvent components used for comparison were
Each was prepared at the mixing ratio shown in the table.

[Appearance Test I-J To visually observe the whitening phenomenon and foaming phenomenon at the adhesive interface, the substrate and the adherend with a thickness of 2 mm were tested at
Cut into squares of mm, room temperature 25°C5 relative humidity 50%
, a pressing force of 0.03 Kg/cm2, a pressing time of 24 hours, and a substrate using an adhesive consisting of each composition of Examples (Nα1 to 7) and Comparative Examples (Nα8 to 15) using a conventional method. A sample was prepared by adhering an adherend to the surface of the acrylic film.

As shown in Table 1, as a result of the visual test, neither whitening nor foaming was observed in this invention.

[Strength test] Board and 3mm thick adherend material 20mm vertically and 100m horizontally
The re-sample was cut into a rectangle with a width of 5 mm and a width of 5 mm on the short side using each adhesive of the Example and Comparative Example under the conditions of an initial clamping force of 12 Ktg/cm'' and 7 days of storage. A sample was prepared by adhering an adherend to the acrylic film surface of the substrate.

Each sample was rated 10no according to JIS K6850.
As shown in Table 1, as a result of a tensile test conducted at a tensile speed of /min, all of the products of the present invention exhibited adhesive strength sufficient for practical use.

(Margin below) 9- 10= 1

Claims (1)

[Claims] When adhering an acrylic resin material to the surface of a substrate made of a polycarbonate resin plate with an acrylic film layer provided on the surface, 100 parts by weight of 1,4-dioxane and 1,4-dioxane were used.
A bonding method characterized by using an adhesive prepared by mixing 25 to 45% by weight of 1,1-dichloroethane to a mixed solvent consisting of 5 to 15 parts by weight of 1,1-trichloroethane.