JPS6111185B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a laminate made by gluing metal foil and polyolefin sheets together via an adhesive film.
The present invention relates to a method for manufacturing a laminate with good adhesive properties, a high surface smoothness that can withstand severe bending and drawing, and no surface irregularities.

Conventionally, as a method of improving the adhesive strength between the polyolefin sheet and the metal foil in a laminate of metal foil and polyolefin sheet, one method is to interpose the adhesive film between the metal foil and the polyolefin sheet. Two known methods include improving the manufacturing conditions in the manufacturing process.

As an example of the first method, US Pat. No. 3,616,019 describes a method in which a thin outer metal layer is bonded to a relatively thick inner thermoplastic layer with an adhesive film of specific physical properties and composition.

The second method is, for example, U.S. Pat.
No. 3,634,166 describes a method in which a thin adhesion-promoting intermediate layer having specific physical properties is laminated on both sides of polyethylene, and then a metal plate is laminated while applying pressure with a roller.

Furthermore, Japanese Patent Application Laid-open No. 53-88884 discloses a method for producing a laminate by laminating metal foil on both sides of a polyolefin layer, in which part or all of the polyolefin is coated on both sides of a molten polyolefin sheet whose temperature is above the melting point and below 280°C. A metal foil is applied with an adhesive layer interposed between 99 to 70 parts by weight of a modified polyolefin grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof and 1 to 30 parts by weight of a hydrocarbon elastomer. A method for producing a laminate with good adhesiveness, which is characterized by bonding under pressure, is described.

In the above method, it is unclear what specific steps are used to manufacture the laminate in the first method, and in the second method, when attaching thin films to both sides of the polyethylene sheet, Film is very weak, so even if you just roll it and press it against a polyethylene sheet, you won't be able to get even adhesion between the film and the polyethylene sheet, and you won't be able to get good adhesive strength and it will fail. The rough laminate also had an uneven surface, making it impossible to obtain one suitable for molding.

Furthermore, in the method described in JP-A-53-88884, it is not possible to obtain uniform adhesion between the adhesive film and the metal foil, and a gap may occur between the metal foil and the polyolefin sheet of the manufactured laminate. As a result, the surface of the laminate became uneven and had poor smoothness, making it difficult to obtain good adhesion. For this reason, when the laminates obtained by the above-mentioned methods are subjected to processing such as bending with a small radius or drawing in order to form a certain shape, the processed parts In this process, peeling easily occurs between the metal foil and the polyolefin, which often causes breakage when the molded product is used.

Therefore, as a result of intensive research, the present inventors applied tension to the adhesive film in a direction transverse to the flow direction of the film before pasting the adhesive film and metal foil together, and then pasted the adhesive film and metal foil together. By manufacturing the laminate under pressure so that the adhesive film and the polyolefin sheet face each other on both sides of the polyolefin sheet, uniform adhesion is achieved between the metal foil and the polyolefin sheet, which results in extremely high adhesive strength. We have successfully made it possible to manufacture a laminate that is resistant to heat and does not break even when subjected to processes such as bending with a small radius or drawing.

The above objects and further objects and advantages of the present invention will become more apparent from the following description.

In the present invention, a laminate consisting of five layers, in which the first layer and the fifth layer are metal foil, the second layer and the fourth layer are adhesive films, and the third layer is a polyolefin sheet, is first prepared. Layer, 5th layer and 4th layer,
Next, in the method of manufacturing a laminate by laminating the second layer on one side of the molten polyolefin sheet and the fourth layer on the remaining side under pressure, the first layer and the fifth layer are laminated, respectively. A method characterized by applying tension in the transverse direction to the film flow direction to each of the second layer and the fourth layer, and then bonding the first layer and the second layer and the fifth layer and the fourth layer. It provides:

FIG. 1 is a schematic enlarged sectional view of an example of a laminate obtained by the method of the present invention, in which metal foil layers 1 and 5, adhesive film layers 2 and 4, and polyolefin sheet layer 3 are laminated as shown in the figure. It is what it is.

core material polyolefin sheet 3 and adhesive layer 2,
The polyolefins used as raw materials for the modified polyolefin in No. 4 include ethylene, propylene, 1-butene,
A homopolymer of α-olefin such as 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene or one of the above monomers and 10 mol% or less, preferably 7 mol% or less There are copolymers with other α-olefins or mixtures thereof with a crystallinity of 25% or more by X-ray analysis, and copolymers of the above α-olefins with acyloxy, especially acetoxy substituted substances such as vinyl acetate. There are combinations or saponified products of these. Among these, medium-low density polyethylene, polypropylene, and densities of 0.910 g/cc to 0.970 g/cc,
It is preferable to use polyethylene having a melt index (190° C.) of 0.05 to 100.

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-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-monobutyramide, fumaric acid -N,N- Examples include dibutylamide, maleimide, N-butylmaleimide, N-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 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.

Hydrocarbon elastomers that are other components of the adhesive layer include, for example, polyisobutylene, ethylene-propylene rubber, ethylene-1-butene rubber, butyl rubber, butadiene rubber, styrene-butadiene rubber, ethylene-butadiene rubber, isoprene rubber, etc. . Among these, ethylene-propylene rubber and polyisobutylene are most preferred.

The polyolefin layer and adhesive layer of the core material used in the present invention contain heat-resistant stabilizers, weather-resistant stabilizers, lubricants, antistatic agents, nucleating agents, coating materials, dyes, flame retardants, and anti-blocking agents to the extent normally used. , a slip agent, etc. may be added.

The adhesive layer contains 99 to 70 parts by weight of a modified polyolefin, preferably 97 to 80 parts by weight, and 1 to 30 parts by weight, preferably 3 parts by weight of a hydrocarbon elastomer.
and 20 parts by weight (total 100 parts by weight) of the composition. If the amount of the hydrocarbon elastomer is less than 1 part by weight, no effect of improving adhesion will be observed, and if it is more than 30 parts by weight, there will be problems in film formability.

The adhesive layer is usually prepared as a film of about 10μ to 100μ by T-die molding or inflation molding. Although there is no problem with increasing the thickness of the film of the adhesive layer, it is not economically preferable.

The metal foil of the laminate includes aluminum, iron, copper,
Metals such as tin and nickel, and one or two of these
There are metals whose main components are more than 10%, such as stainless steel. Among these, aluminum is preferably used. Metal foil is 0.01 to 0.5mm
It is about the same thickness and is prepared by degreasing.

Further, a small amount of an inorganic compound such as a lubricant or a filler may be added to the adhesive layer to improve adhesiveness. Inorganic compounds include magnesium oxide, calcium oxide, aluminum oxide, titanium dioxide,
Examples include magnesium sulfate, calcium sulfate, magnesium hydroxide, and aluminum hydroxide.

In the present invention, the first layer and the second layer, the fifth layer and the fourth layer
Before laminating the layers, tension is applied to the second layer and the fourth layer in a direction transverse to the film running direction, and then the first layer and the second layer and the fifth layer and the fourth layer
The layers are pasted together, but by doing this, when the adhesive film is pasted onto the metal foil, the creases of the adhesive film may overlap, or the film may not adhere evenly to the metal foil, causing the film and metal foil to overlap. As a result, the adhesive strength between the metal foil and the film can be improved, and at the same time, the adhesive strength between the metal foil and the polyolefin can be improved, allowing for small radius bending and drawing. It is possible to prevent peeling of the metal foil and adhesive film from areas where the adhesive strength has decreased during processing, and it has become possible to produce molded products without breakage.

At the same time, by using this manufacturing method,
When bonding the adhesive film and polyolefin sheet, the adhesive film is backed with metal foil and is strongly supported, so the adhesive film and polyolefin sheet adhere uniformly and firmly, resulting in a strong product as a whole. available.

There are various methods for applying tension in the direction transverse to the flow direction of the adhesive films of the second and fourth layers, but one preferred method is to use a roll whose rotating axis forms an arc. There is a method of applying tension in a direction transverse to the flow direction of the adhesive film by passing the adhesive film over the adhesive film.

As such a roll, it is more preferable to use a roll whose surface is made of rubber having a large coefficient of friction.

As an example of such a roll, the one shown in FIG. 3 will be explained.

In FIG. 3, reference numeral 1 denotes a flexible curved shaft which is fixed so as to remain bent as a whole.

A rubber roll 2 is configured to rotate around the curved shaft 1 via a special bearing 3 on the curved shaft 1.

Reference numeral 4 denotes an angle adjustment device that determines the degree of bending of the curved axis 1.

In FIG. 4, the adhesive film 42 starts contacting the roll from the A side, and as the rubber roll expands as it advances toward the B side, the frictional force between the rubber and the film causes the film to move in the direction of travel of the film. This is where lateral tension acts.

FIG. 2 of the accompanying drawings is an example of a diagram of an apparatus for explaining an aspect of the above invention.

The metal foils 1 and 1' are degreased in advance and prepared by being wound into rolls, passed through guide rolls 3, 3', 4, and 4', and heated to approximately 70°C to 200°C in preheaters 6 and 6'. , to the roll pair 5, 5'. Preheater 6,
6', the temperature is 100-300℃, preferably 150-250℃
If a method that blows hot air at ℃ is used, there will be less temperature unevenness and the metal foil can be preheated with high thermal efficiency. In addition, after the metal foil is degreased,
You may also prepare the exterior by painting it. roll vs. 5,
The temperature of 5' is preferably 100 to 150°C.

a pre-formed thin film 2 serving as an adhesive layer;
2' is supplied to rolls 20, 20', and as it passes through the rolls, a force is applied perpendicular to the direction of film flow, and then the roll pair 5,
5' and bonded onto metal foil to form a two-layer laminate, heated to 120°C with heaters 7 and 7' as needed.
The material is heated to about 200°C and laminated. In the apparatus shown in Fig. 2, two-layer laminates are continuously and simultaneously formed, but the two-layer laminates are formed by laminating various types of adhesive layers on metal foil elsewhere beforehand, and then the molten polyolefin is It may also be supplied onto the sheet 9. In this case, heating by the heaters 7, 7' is not particularly required.

Melting polyolefin sheet has melting point above 280℃
It is melt-extruded from an extruder 8 at the following temperature and fed between pressure rolls 10, 10'. Its thickness is usually between 1 mm and 6 mm. If the temperature of the molten polyolefin sheet is below the melting point, it will not adhere, and if it exceeds 280°C, the adhesiveness will actually decrease.

The pressure rolls 10, 10' are set at room temperature to 300°C, and after the two-layer laminate is pressed onto both sides of the molten polyolefin sheet, it is sent to a plurality of pairs of cooling rolls 11, 11'. The laminate 12 is cooled and is pressurized to 0.1Kg/cm ² to 4Kg/cm ² as it passes between the rolls 11 and 11', and the completely crimped laminate is taken off by a take-off machine 13 and cut. It becomes a product.

Example 1 High density polyethylene (melt index
A modified polyethylene was prepared by grafting 1.0% by weight of maleic anhydride onto 1.5% by weight of maleic anhydride and 90 parts by weight of medium density polyethylene (melt index: 4.0, density: 0.925).

A composition consisting of 90 parts by weight of this modified polyethylene and 10 parts by weight of polyisobutylene (trade name: Vistanex MML-80, manufactured by Etsuso Corporation, hereinafter abbreviated as PIB) was molded into a 20μ inflation film at a resin temperature of 220°C, and an adhesive film was formed. did.

Using high-density polyethylene (melt index 1.0, density 0.957, melting point 120°C) as the core material and aluminum foil with a thickness of 0.2 mm as the metal foil, the second
A laminate was manufactured using the apparatus shown in the figure. However, the extrusion temperature of the molten polyolefin sheet 9 is 250°C, the set temperature of the pressure rolls 10 and 10' is 200°C, and the cooling roll 1 is
The pressure at 1,11' was between 0.1 Kg/cm ² and 4 Kg/cm ² .

The manufactured laminate had good smoothness with no irregularities on the surface. Even when the laminate was bent, no peeling occurred between the metal foil and the polyethylene sheet, and no breakage occurred.

Example 2 A modified polypropylene was prepared consisting of 10 parts by weight of a modified product obtained by grafting 1.0% by weight of maleic anhydride onto polypropylene (melt index 7.0, density 0.91) and 90 parts by weight of polypropylene (melt index 6.5, density 0.91). .

This composition consisting of 90 parts by weight of modified polypropylene and 10 parts by weight of polyisobutylene was heated to resin temperature.
It was molded into a 50μ T-die film at 240°C to obtain an adhesive film.

Polypropylene core material (melt index)
1.5, density 0.91, melting point 165°C) and using aluminum foil with a thickness of 0.2 mm as the metal foil, Example 1
A laminate was produced in the same manner. However, the extrusion temperature of the molten polypropylene sheet is 230℃, and the pressure roll 1
0,10' set temperature 220℃, cooling roll 11,1
The pressure at 1' was 0.1 to 4 kg/cm ² .

The obtained laminate had good smoothness with no irregularities on the surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a laminate manufactured by the method of the present invention. FIG. 2 is a schematic diagram showing a specific example of the method of the present invention. FIG. 3 is a cross-sectional view of a curved roll that applies lateral tension to the adhesive film.
FIG. 4 is a perspective view showing the adhesive film passing over the curved roll. [Explanation of symbols of main parts] (in Figure 2)
1, 1'...Metal foil, 2, 2'...Adhesive film, 3,
3', 4, 4'...Guide roll, 5,5'...Roll pair, 6,6'...Preheater, 7,7'...Heater, 8...Extruder, 9...Polyolefin sheet, 10,10'
...Pressure roll, 11, 11'...Cooling roll, 12
... Laminate plate, 13... Take-up machine, 20, 20'... Curved shaft roll (expanding roll).

Claims (1)

[Claims] 1. The first layer and the fifth layer are metal foil, and the second layer and the fourth layer are metal foil.
A laminate consisting of five layers, in which the first layer is an adhesive film and the third layer is a polyolefin sheet, is first laminated with the first layer and the second layer and the fifth layer and the fourth layer, and then with the molten polyolefin sheet on one side. In a method of manufacturing a laminate by bonding two layers and a fourth layer on the remaining one side under pressure, the second layer and the fourth layer are bonded to each other before being bonded to the first layer and the fifth layer, respectively. A method characterized by applying tension in the transverse direction to the flow direction of the film, and then bonding the first layer and the second layer, and the fifth layer and the fourth layer. 2 99 to 70 parts by weight of a modified polyolefin in which part or all of the polyolefin in the second and fourth layers is grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof, and a hydrocarbon elastomer 1 2. The method of claim 1, wherein the adhesive layer comprises from 30 parts by weight to 30 parts by weight. 3 The polyolefin layer has a density of 0.910 g/cc or
0.97g/cc, melt index (190℃) 0.05
The method according to claim 1, characterized in that the polyethylene has a polyethylene content of from 1 to 100%. 4. The method according to claim 1, wherein the modified polyolefin is a modified polyolefin modified with maleic anhydride. 5 Grafting ratio of unsaturated carboxylic acid or its derivative to polyolefin is 10 ^-4 to 3% by weight
The method according to claim 1, characterized in that: 6. The method according to claim 1, wherein the hydrocarbon elastomer is polyisobutylene or ethylene-propylene rubber. 7. The method according to claim 1, wherein the metal foil is an aluminum foil with a thickness of 0.01 mm to 0.5 mm. 8. Before laminating the first layer and the second layer and the fifth layer and the fourth layer, the second layer and the fourth layer are each passed through rolls whose rotational axes form an arc. A method according to claims 1 to 7.