JPH0115380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of bonding a polyolefin sheet and a metal plate.

Laminated boards in which metal plates or metal foils are laminated on a polyolefin layer are widely used for civil engineering, architecture, furniture, and decoration. As a method for improving the adhesion between the polyolefin layer and the metal plate of these laminates, there are methods of modifying the polyolefin, such as blending unsaturated carboxylic acids or derivatives thereof into the polyolefin, or adding these monomers to the polyolefin. Graft polymerization is being carried out.
It is also known to treat the surface of a metal plate with an acid or the like. However, when adhering these modified polyolefin materials to metal plates, the conventional method of obtaining sufficient adhesive strength was to heat and melt the modified polyolefin material above its melting point. When a sheet with a diameter exceeding 5 mm is bonded to a metal plate, the shrinkage rate of the polyolefin layer and the shrinkage rate of the metal are greatly different, so unless a sandwich structure is used, the laminate will warp, making it impossible to obtain a laminate that can withstand practical use. There was a drawback that there was no. Therefore, the current method of attaching a polyolefin sheet with a thickness of 5 mm or more to a metal plate to obtain a two-layer laminated board is mechanical attachment using bolts, etc., but with this method, the bolts are exposed on the sheet surface. , or there are disadvantages such as the installation work being time-consuming. Therefore, the inventors developed a 5 mm thick
As a result of research into a method for bonding a polyolefin layer and a metal plate described above in which the laminate does not warp after bonding, the present invention was achieved.

That is, the present invention performs a surface treatment on the adhesive surface in advance and heats the metal plate to a temperature higher than the melting point of polyolefin.
A film made of a modified polyolefin in which part or all of the polyolefin is grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof is placed on the metal plate, and a polyolefin sheet with a thickness of 5 mm or more is further placed on the film. The object of the present invention is to provide a method for producing a laminate, which is characterized in that the polyolefin sheets are laminated together under pressure at a pressing temperature below the softening point of the polyolefin sheets.

Polyolefins used as raw materials for polyolefin sheets and modified polyolefin films for the adhesive layer include ethylene, propylene, 1-butene, and 1-butene.
A homopolymer of α-olefin such as pentene, 3-methyl-1-pentene, 1-hexene, 4-methyl-1-pentene or one of the above monomers
10 mol% or less, preferably 7 mol% or less of other 1
There is a copolymer or a mixture thereof with more than one species of α-olefin and a polymer with a crystallinity of 25% or more by X-ray analysis, and furthermore, the above α-olefin and
-Olefin acyloxy, especially acetoxy-substituted products, such as copolymers with vinyl acetate, or saponified products thereof. Among these, homopolymers of ethylene or propylene or copolymers mainly composed of these are preferred, and among them, polyolefin sheets with a melt index (ASTM D 1238E) of 1.0 g/10 min or less, especially
Ultra-high molecular weight polyethylene of less than 0.01 g/10 min is preferable because it has excellent wear resistance, impact resistance, self-lubricating property, and low temperature resistance. In addition, when using high molecular weight polyethylene as described above as the polyolefin sheet layer, use a modified ethylene polymer or copolymer as the adhesive layer, especially an ethylene polymer or copolymer with a melt index of 0.1 to 15 g/min. It is preferable to use

The modified polyolefin, which is a component of the adhesive layer, is produced by graft-modifying part or all of the above polyolefin with an unsaturated carboxylic acid or a derivative thereof.

Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, and citraconic acid. Further, derivatives of unsaturated carboxylic acids include acid anhydrides, esters, amides, imides, metal salts, etc., such as maleic anhydride,
Citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, monoethyl maleate, diethyl maleate ester , fumaric acid monomethyl ester, fumaric acid dimethyl ester,
Itaconic acid monomethyl ester, methaconic acid diethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N,N-diethylamide, maleic acid-N
-Monobutylamide, maleic acid-N,N-dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid-N-monoethylamide, fumaric acid-N,N-diethylamide, fumaric acid-N-monobutylamide, Fumaric acid-N,N-dibutylamide, maleimide, N-butylmaleimide, N-
Examples include phenylmaleimide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, and the like. Among these, it is most preferred to use maleic anhydride.

Various known methods can be used to graft the above monomer onto the polyolefin. For example, it is carried out by heating the polyolefin and the grafting monomer at high temperature in the presence or absence of a solvent with or without the addition of a radical initiator. Other vinyl monomers such as styrene may be present during the reaction. The amount of the graft monomer grafted onto the polyolefin (hereinafter referred to as graft ratio) is preferably adjusted to be in the range of 10 ^-4 to 3% by weight. The polyolefin may be partially or completely grafted, but from the viewpoint of industrial production, the grafting ratio is 10 ^-2 in advance.
It is preferable to prepare a modified polyolefin in an amount of 6% to 6% by weight and then mix the modified polyolefin with an unmodified polyolefin, since this allows the concentration of the graft monomer in the composition to be adjusted appropriately.

The adhesive layer may further contain a hydrocarbon elastomer such as polyisobutylene, ethylene-propylene rubber, ethylene-1-butene rubber, butyl rubber, butadiene rubber, styrene-butadiene rubber, ethylene-butadiene rubber, isoprene rubber, and the like. Among these, ethylene-propylene rubber and polyisobutylene are most preferred.

The polyolefin sheet and adhesive layer used in the present invention contain heat-resistant stabilizers and
Weathering stabilizers, lubricants, antistatic agents, nucleating agents, pigments, dyes, flame retardants, antiblocking agents, slip agents, etc. may be blended.

The modified polyolefin film used as the adhesive layer is usually a film obtained by T-die molding method, inflation molding method, etc., and preferably has a thickness of
It is a 10μ to 100μ film. Films with a thickness of more than 100 microns can also be used in this method, but the melting time is longer, so it takes longer to form.

Polyolefin sheets are usually obtained by compression molding, extrusion molding, etc., and have a thickness of 5 mm or more, preferably 10 mm or more. Thickness is 5
A sheet with a diameter of less than 1 mm is undesirable because it melts when bonded to a metal plate and shrinks after cooling, causing warpage in the laminate.

The metal plate is a plate made of a metal such as aluminum, iron, copper, tin, or nickel, or a metal whose main component is one or more of these metals. Among these, iron plates are preferably used. 1 to 5 metal plates
It has a thickness of about mm, and is prepared by surface treatment of the adhesive surface, such as degreasing treatment or sandblasting treatment, and further primer treatment such as epoxy resin coating.

In the method of the present invention, the metal plate whose adhesive surface has been surface-treated is heated to a temperature higher than the melting point of the polyolefin and modified polyolefin, preferably higher than the melting point +20°C.
Heating to a temperature of 280°C or less, stacking a polyolefin sheet with a thickness of 5 mm or more on the metal plate via the modified polyolefin film, and pressing at a pressing temperature below the softening point of the polyolefin sheet, preferably 30°C or less. Condition, preferably 1 to 10Kg/
This is a method for producing a warp-free laminate of polyolefin and metal plates by bonding them together under a pressure of cm ² G. If the heating temperature of the metal plate is below the melting point, a laminate with sufficient adhesive strength cannot be obtained, and if the heating temperature exceeds 280°C, the modified polyolefin film may deteriorate due to heat, which is not preferable. When bonding a polyolefin sheet to a metal plate, the pressing temperature must be below the softening point. At temperatures above the softening point, if the polyolefin sheet is melted by the heat from the metal plate and made into a laminate,
This is not preferable because it causes warping. In addition, the obtained laminate may be subjected to secondary processing such as press processing depending on the purpose.
It is bent and processed into the final product.

The laminate of the present invention has the abrasion resistance, impact resistance, chemical resistance, non-adhesiveness of the oriolefin sheet, good sliding properties (low coefficient of friction), hygiene, the rigidity of the metal plate,
Taking advantage of both characteristics of weldability, it is suitable for lining materials (shooters, hoppers, conveyor lines), etc. for various industrial applications such as agriculture, civil engineering, coal industry, and steel industry.

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded.

Example 1 An iron plate (SS-41, size 300 x 500 x 3.2 mm) that had been previously degreased with toluene was sandwiched between heat presses and heated to 210°C. Next, a modified polyolefin film (Mitsui Petrochemical Industries, Ltd.) with a thickness of 80μ was placed on the heated iron plate.
Place a sheet (300 x 500 x 15 mm) of ultra-high molecular weight polyolefin (made by Mitsui Petrochemical Industries, Ltd., Hi-Zex Million 240M) on top of it (manufactured by Mitsui Petrochemical Industries, Ltd.).
These laminates were immediately placed on a cooling press (20° C.) and cooled under a pressure of 5 kg/cm ² G. The cooling time was 5 minutes. The laminate taken out after cooling had no warpage at all.

The performance of the laminate was measured by the following method.

Peel strength (Kg/cm): Width 20mm x length 150 from laminate
After cutting a mm test piece and peeling off one end of the laminate, it was grasped with a chuck and used a tensile tester (Instron TMM model (USA) manufactured by Instron Corporation).
The strength was measured at a tensile speed of 200 mm/min, and the maximum strength was defined as the peel strength (Kg/cm).

Shear strength (Kg/cm ² ): Width 20mm x length 150 from laminate
Cut a test piece of 20 mm in length, then cut out a 5 mm wide piece of ultra-high molecular weight polyethylene sheet and a steel plate, leaving a 20 mm long adhesive part in the center, grip both ends with a chuck, and perform the tensile test as described in the previous section. The shear strength was measured using a machine at a tensile speed of 10 mm/min.

As a result, the peel strength was 25Kg/cm, and the shear strength was 30Kg/cm.
It was Kg/ ^cm2 .

Example 2 Iron plate (SS-41, 300×
500 x 3.2 mm) with an epoxy resin (Epoxy, Primer R, Toa Paint Co., Ltd.), and then a laminate was obtained in the same manner as in Example 1. As a result, there was no warping of the laminate, and the peel strength was 35.
kg/cm2, and the shear strength was 40 Kg/ ^cm2 .

Comparative Example 1 The same method as in Example 1 was carried out except that the modified polyolefin film used in Example 1 was not used. As a result, there was no warpage in the laminate, but both peel strength and shear strength were zero.

Comparative Example 2 The iron plate degreased with toluene in Example 1 was used, except that an epoxy adhesive (main agent R-130, curing agent Q-611, manufactured by Mitsui Petrochemical Industries, Ltd.) was used instead of the modified polyolefin film. The same procedure as in Example 1 was carried out. As a result, the laminate did not warp, but its peel strength was 1.5 kg/cm 2 and its shear strength was 25 kg/cm ² .

Comparative Example 3 The iron plate degreased with toluene from Example 1 was heated to 200°C on a heat press, and then the modified polyolefin film used in Example 1 was placed on it, surrounded by a metal frame, and then the iron plate used in Example 1 was heated to 200°C. The ultra-high molecular weight polyethylene powder was placed in a metal frame, and then pressurized (40 Kg/cm ² G) at 200°C for 10 minutes, followed by cooling in a cooling press at 20°C for 10 minutes to obtain a laminate. The resulting laminate was significantly warped with the ultra-high molecular weight PE on the inside.
However, the peel strength is 25Kg/cm, and the shear strength is 30Kg/ ^cm2.
It was hot.

Claims (1)

[Claims] 1 A metal plate whose adhesive surface has been surface-treated is heated to a temperature higher than the melting point of the polyolefin, and part or all of the polyolefin is coated with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof. Production of a laminate, characterized in that a film made of grafted modified polyolefin is further laminated with a polyolefin sheet with a thickness of 5 mm or more on top of the film, and the laminated board is bonded together under pressure at a pressing temperature below the softening point of the polyolefin sheet. Method.