JPH0224652B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method of joining thick plastic sheets using a heat seal tape comprising a specific hot melt type adhesive layer and a crosslinked polyolefin layer.

Recently, attempts have been made to spread wide, thick plastic sheets over irrigation rivers, small ponds, etc. to prevent water from seeping into the ground.

In general, it is difficult to obtain thick plastic sheets of approximately 1 mm or more by directly molding a wide sheet from a molding machine, and the width of a thick sheet directly molded from a molding machine is approximately 200 cm in the largest class.
Therefore, in order to manufacture thick plastic sheets with wide widths, a plurality of sheets were pasted together and connected.

However, the method of bonding thick plastic sheets together is usually by heat-sealing the thick sheets, but this heat-sealing process is difficult because thick sheets have poor thermal conductivity. It is extremely difficult to do this, and in reality, it is only carried out in factories equipped with special equipment (even the wide sheets produced at these factories have a width limit of about 10 meters at most). It was not possible to easily connect long thick sheets at irrigation construction sites such as rivers and ponds.

Therefore, the above-mentioned attempts to waterproof irrigation systems using wide, thick plastic sheets have rarely been implemented.

As a result of intensive research into a method for easily connecting thick plastic sheets at construction sites, the inventors used a heat-seal tape consisting of a specific hot-melt adhesive layer and a cross-linked polyolefin layer. Then, connect the thick plastic sheets by gluing the heat-sealing tape to the edge of the thick plastic sheet at a low temperature of about 50 to 110℃, and then heating the heat-sealing tape to a high temperature and bonding. He found a way to do this and completed this invention.

That is, the present invention provides a heat seal tape comprising a hot melt type adhesive layer containing at least 10% by weight of an adhesive component having a melting point within the range of about 50 to 110°C, and a crosslinked polyolefin layer. , the adhesive layer of the heat seal tape and/or
Or preheat the surface of the edge to about 50~
The heat-sealing tape is adhered at a temperature of 110℃, and then heating and pressing force is applied at a temperature of approximately 120 to 250℃ from the outer surface of the heat-sealing tape to be adhered to the edge of the thick plastic sheet. The present invention relates to a method for connecting thick plastic sheets, which is characterized by bonding a thick plastic sheet and a heat seal tape.

The method of the present invention connects sheets by heating, but does not give a large thermal history to areas other than the edges of thick plastic sheets, and even the edges can be heated very superficially and for a short time. This prevents thick plastic sheets from rippling or melting during the connection process.

In addition, the joints of the connected thick plastic sheets obtained by the method of the present invention can be temporarily bonded with heat-sealing tape, and then hot-melt type bonding is performed to prevent the joints from being subjected to large thermal hysteresis as described above. Since the adhesive layer is heated and bonded, there are no bubbles or wrinkles on the heated bonding surface, and the connection is made with a strong and waterproof bond. .

Furthermore, since the method of the present invention mainly involves appropriately arranging a thick plastic sheet and a heat-sealing tape, and performing a partial heating operation,
If the necessary materials are available, it can be easily carried out at the construction site or in the factory.

Below, this invention will be explained with reference to the drawings.
I will explain in more detail.

FIG. 1 is a perspective view illustrating a situation in which a heat seal tape is adhered onto the edge of a thick plastic sheet at a temperature range of about 50 DEG to 110 DEG C.

Figure 2 shows a heat-sealing tape that has been bonded onto the edge of a thick plastic sheet at a temperature range of about 50 to 110°C, and then heated to a temperature of about 120 to 250°C. FIG. 3 is a perspective view illustrating a situation in which bonding is performed in a temperature range.

FIG. 3 is a top and side view illustrating plastic sheets connected by the method of the present invention.

The heat-sealing tape used as shown in FIG. A hot-melt type adhesive that contains at least 10% by weight, especially 20 to 100% by weight, of adhesives (tackifiers), polymer components, and other fillers, and can be bonded at low temperatures of approximately 50 to 110°C. This is a heat seal tape 2 consisting of an adhesive layer 3 and a crosslinked polyolefin layer 4.

The hot melt type adhesive layer 3 may be mainly formed of a heat-melting adhesive (hot melt type adhesive) containing an olefin (co)polymer and a tackifier. Preferably, the tack or adhesion force (180 degree peel, pulling speed 10 mm/min, 20°C) to the surface of the thick plastic sheet when bonded at a temperature within the range of about 50 to 110°C as described above is about 0.01 to 1.0. Kg/cm, especially about 0.05 to 0.8 Kg/cm, and furthermore, about 120
It must be made of an adhesive that has an adhesion force of approximately 2.0 to 30 kg/cm, particularly approximately 4.0 to 25 kg/cm, to the surface of a thick plastic sheet when bonded by sufficiently heating to a high temperature of ~250°C. is preferred.

Examples of olefin-based (co)polymers used in such adhesives include polyethylene,
Polypropylene, polyvinyl chloride, ethylene/vinyl acetate copolymer, ethylene/propylene copolymer, ethylene/ethyl acrylate copolymer, ethylene/methyl acrylate copolymer, ethylene/ethyl methacrylate copolymer, etc. (meth)acrylate polymers, ethylene/(meth)acrylic acid copolymers such as ethylene/acrylic acid copolymers, ethylene/methacrylic acid polymers, and modified products of these polymers (e.g., maleated polyethylene, maleated polypropylene, etc.), and they may be used alone or as a mixture of two or more.

Further, the tackifier used in the above adhesive can be arbitrarily selected from tackifiers commonly used in known hot melt type adhesives, and examples of the tackifier include:
Examples include rosin or rosin derivatives, pinene resins, coumaron/indene resins, other aliphatic or alicyclic hydrocarbon resins, and aromatic hydrocarbon resins, among which melting points of about 110°C or less, especially about A temperature of 60 to 100°C is optimal.

In this invention, the adhesive layer provided on the heat seal tape includes, in addition to the above-mentioned components, an inorganic filler such as talc, charcoal, silica, alumina, mica, carbon black, or an antioxidant. , colorants, softeners, and other additives may be added.

In the method of the present invention, as the adhesive, for example, about 50 to 95% by weight, especially 60 to 90% by weight of polyolefin or modified polyolefin (especially ethylene polymer), and a melting point of about 110°C or less,
In particular, a hot melt type adhesive containing as a main component about 5 to 50% by weight, especially 10 to 40% by weight of a tackifier having a temperature of about 60 to 100°C is used.
For the surface of thick plastic sheets (particularly polyolefin sheets) at temperatures within the range of
Adhesive with an adhesive force of 0.01~1.0Kg/cm, and approximately
It is particularly suitable because it can be heated to a high temperature of 120 to 250°C and bonded with an adhesive force of about 2.0 to 30 kg/cm, and the adhesive force after bonding is sufficiently high.

In addition, in this invention, the adhesive layer of the heat seal tape is formed by irradiation with high-energy rays such as electron beams, X-rays, α-rays, β-rays, and γ-rays, or
A moderate degree of crosslinking of the polymer components by chemical reaction with a crosslinking agent such as peroxide is particularly suitable for improving adhesion to thick plastic sheets, and the degree of crosslinking However, it is optimal that the gel fraction is about 5 to 50%, particularly about 10 to 40%, as described below.

The above gel fraction is calculated by putting the sample to be measured in xylene, dissolving it under reflux at a temperature of about 10°C for about 10 hours, and calculating the weight (Ag) of the sample that did not dissolve in the xylene. , is the value obtained by dividing by the weight (Bg) of all the samples used and multiplied by 100.

Gel fraction = (A/B) x 100 (%) The crosslinked polyolefin layer 4 of the heat seal tape used in the method of the present invention is, for example,
Mainly composed of olefin polymers such as polyethylene, polypropylene, ethylene/propylene copolymer, ethylene/vinyl acetate copolymer, and other polymers, plasticizers, antioxidants, flame retardants, and fillers. (carbon black, silica, alumina, mica, carbon black, etc.), a coloring agent, etc., is made into a polyolefin film or sheet (about 100 to 3000μ thick, especially 150～
2500μ) and crosslinked with electron beams, X-rays, alpha rays, gamma rays, etc.; The degree of crosslinking is approximately 20 to 90%, especially 30 to 80%, as indicated by the gel fraction.
% is preferable.

The above-mentioned heat-seal tape is produced by, for example, forming a polyolefin film or sheet by extrusion molding from the above-mentioned polyolefin resin composition, and coating the film or sheet by a lamination method in which an adhesive is extruded onto the film or sheet to form an adhesive layer. and then crosslinking the laminate (sheet) from the adhesive layer side with an electron beam or the like to produce a tape consisting of a partially crosslinked adhesive layer and a crosslinked polyolefin layer, In addition, a cross-linked polyolefin film or sheet and an adhesive sheet are separately manufactured, and a laminate (sheet) is formed by bonding them together, and then cross-linked from the adhesive layer side by electron beam irradiation, etc. It can also be manufactured by

In this invention, the thickness of the adhesive layer and the crosslinked polyolefin layer in the heat seal tape is not particularly limited, but for example, the thickness of the adhesive layer is about 0.1 to 3.0 mm, particularly 0.1 mm. ~2.5mm
The thickness of the crosslinked polyolefin layer is approximately
The thickness is about 0.1 to 3.0 mm, and the thickness ratio of the adhesive layer to the crosslinked polyolefin layer is about 1:10 to
3:1, and furthermore, the overall thickness of the heat seal tape should be about 0.5 to 5 mm, especially about 1 to 4 mm, in order to have flexibility that is convenient for handling, or to have sufficient mechanical strength after connection. It is preferable because it has an objective strength. Also, the width of the heat seal tape (the length perpendicular to the longitudinal direction of the tape)
is preferably about 5 to 50 cm, particularly about 10 to 50 cm.

In addition, in the present invention, the heat seal tape is further provided with a heat-resistant and/or flame-resistant reinforcing material layer (for example, a glass cloth layer, an aluminum foil layer, an asbestos layer, etc.) on the outside of the crosslinked polyolefin layer. It may be.

In the method of this invention, first, as shown in FIG. 1, two thick plastic sheets 1, 1' are arranged with their edges to be connected partially overlapped, The aforementioned adhesive layer 3
and a cross-linked polyolefin layer 4, the two thick sheets 1, 1'
The surfaces of the adhesive layer 3 of the heat-sealing tape 2 and/or the edges of the thick sheets 1, 1' are coated along the edges to be connected, for example, while overlapping them. , preheat with the flame of gas burner 5, etc. to about 50 to 110℃, especially 60℃.
The heat seal tape 2 is bonded (and/or adhesive) at a low temperature of ~100°C.

In the method of the present invention, in the operation of overlapping the heat seal tape 2 described above along the edges of the thick sheets 1 and 1' to be connected, the supply of the heat seal tape 2 is It is preferable to do this under tension.

In addition, as mentioned above, when the end edges of two thick plastic sheets 1 and 1' to be connected are arranged so as to partially overlap each other, there is a gap between the overlapped end edges. If both sheets are temporarily fixed using double-sided tape, etc., the overlapped portions of both sheets will not shift, making it easier to adhere the heat seal tape described above at a temperature range of approximately 50 to 110 degrees Celsius. Therefore, it is preferable.

Further, in the method of the present invention, in the work of adhering the above-mentioned heat seal tape at a temperature range of about 50 to 110°C, for example, a pressing roll 6 (for example, a metal By applying a pressing force with a roll, a rubber roll, a sponge roll, a stepped roll, etc., or a combination roll thereof, the heat seal tape 2 is applied to the edge of the thick polyolefin sheet to be connected (particularly when the pressure is applied during overlapping). This is desirable because it allows for uniform adhesion over the entire surface (with respect to stepped portions).

In this invention, it is particularly important that the specific heat-sealing tape is once bonded onto the edges of the thick plastic sheets to be connected at relatively low temperatures. That is, in this invention, by performing this preliminary step, the subsequent main adhesion work can be performed without causing wrinkles or misalignment of the heat seal tape, and without causing any wrinkles or misalignment between the heat seal tape and the thick sheet. This is done effectively without creating bubbles or peeling, and it does not give excessive heat history to thick sheets.
The thick sheet itself will not be thermally deformed (curled), wrinkled, or melted and torn, and the durability of the thick sheet will hardly be impaired.

In the method of the present invention, following the above-described bonding of the heat-sealing tapes at a temperature range of approximately 50 to 110°C, the bonded heat-sealing tape 2 is bonded to its outer surface as shown in FIG. For example, with the flame of gas burner 5', about 120 to 250
℃ and apply pressing force with the same pressing roll 6' as described above (especially elastic roll, sponge roll, etc.) to heat seal the edges of the thick plastic sheets 1, 1'. The tape 2 is bonded (fused) at a high temperature of approximately 120 to 250°C, particularly 130 to 200°C.

In this invention, in the above-mentioned high-temperature bonding, the flame of the gas burner 5' is about 50 to 110°C.
In order to prevent the heat-sealing tape 2 from reaching the outside of both ends of the bonded heat-sealing tape 2 in the temperature range of It is appropriate to arrange it on the surface of thick sheets on both sides of the tape 2 which are overlapped.

In this invention, the preheating and high-temperature heating described above are not only performed using the flame of the gas burner, but also using other known heating means, such as an electric heater, an infrared heater, another hot wire heater, a heating roll, The pressing may be carried out using an electric iron, spraying a heating medium, or the like, and other pressing means may also be used for the pressing roll.

Furthermore, in the method of the present invention, for example, after completing the bonding operation of the heat seal tape in the temperature range of about 50 to 110 degrees Celsius, the subsequent heat bonding operation at a high temperature may be performed, or both operations may be performed. It is also possible to carry out these operations in close succession almost simultaneously with a slight time difference.

The method of this invention can connect thick plastic sheets with extremely simple operations, so it can be used at construction sites of irrigation rivers, reservoirs, etc. with a width of 2 m.
A large number of the following thick plastic sheets can be connected one after another to form a long wide sheet and installed at the same time.

The thick plastic sheets to be connected by the method of this invention can be used in any material that can be installed in irrigation rivers, reservoirs, etc. and exhibit sufficient durability, weather resistance, mechanical strength, and waterproofness. It may be a plastic sheet of the type, for example:
Polyethylene, polypropylene, polyvinyl chloride, ethylene/vinyl acetate copolymer, ethylene/
Molded from a resin composition whose main component is an olefin polymer such as propylene copolymer.
It is about 0.5 to 5 mm, especially about 1 to 4 mm, and the width is about 50 to 50 mm.
A polyolefin sheet (particularly a sheet of ethylene polymer such as polyethylene or ethylene/vinyl acetate copolymer) having a length of 200 cm is suitable.

As shown in FIG. 3, the plastic (polyolefin) sheets connected by the method of the present invention have a heat-sealing tape attached to the parts where the end edges of the thick plastic sheets 1 and 1' overlap each other. Since the joint is strongly bonded via the adhesive layer 3, this connection part has sufficient strength and waterproofness, and can be installed on-site in irrigation rivers and reservoirs and used for waterproofing. be able to.

[Brief explanation of drawings]

FIG. 1 is a perspective view illustrating a situation in which a heat seal tape is adhered onto the edge of a thick plastic sheet at a temperature range of about 50 DEG to 110 DEG C. Figure 2 shows a heat-sealing tape that has been bonded onto the edge of a thick plastic sheet at a temperature range of about 50 to 110°C, and then heated to a temperature of about 120 to 250°C. FIG. 3 is a perspective view illustrating a situation in which bonding is performed in a temperature range. Figure 3 shows
1A and 1B are plan and side views illustrating thick plastic sheets connected by the method of the present invention; FIG. 1, 1'; Thick plastic sheet, 2;
Heat seal tape, 3; Adhesive layer, 4; Crosslinked polyolefin layer, 5, 5'; Gas burner, 6,
6'; Pressing roll.

Claims (1)

[Claims] 1. A heat-seal tape comprising a hot-melt adhesive layer containing at least 10% by weight of an adhesive component having a melting point in the range of about 50 to 110°C and a crosslinked polyolefin layer. is placed over the edges of two thick plastic sheets to be connected, while preheating the adhesive layer of the heat seal tape and/or the surface of the edges to approximately Heat-seal tape is adhered at a temperature of 50 to 110 degrees Celsius, and then heated and pressed at a temperature of approximately 120 to 250 degrees Celsius from the outside surface of the adhered heat-seal tape to create a thick plastic sheet. A method for connecting thick plastic sheets, characterized by bonding the edges and heat-sealing tape.