JPH02252551A - Heat-meltable adhesive composite sheet - Google Patents

Abstract

PURPOSE:To obtain excellent uniform adhesive strength by laminating a modified polyolefin sheet modified with unsaturated carboxylic acid or an anhydride thereof having a specific thickness to the outermost layers on both surfaces of a metal sheet having a specific thickness. CONSTITUTION:A heat-meltable adhesive composite sheet is formed by laminating a modified polyolefin sheet modified with unsaturated carboxylic acid or an anhydride thereof to both surfaces of a metal sheet having a thickness of 5-500mum. When the thickness of the modified polyolefin sheet is below 5mum, wrinkles become easy to generate and adhesive strength also becomes unstable and, when said thickness thereof exceeds 500mum, the molding of the sheet itself is easy but adhesion becomes unstable from the aspect of uniform heating. As the metal to be used of the metal plate, there are aluminum, steel, stainless steel, tinplate, copper, brass or nickel but aluminum, steel, stainless steel and tinplate are especially pref. When the thickness of the sheet becomes less than 5mum, wrinkles become easy to generate and, when said thickness exceeds 500mum, workability is damaged.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a composite sheet for hot melt adhesive in which hot melt adhesive resin is laminated on both sides of a metal sheet, and in particular, it relates to a composite sheet for hot melt adhesive, in which hot melt adhesive resin is laminated on both sides of a metal sheet, and in particular, it relates to a composite sheet for hot melt adhesive, in which hot melt adhesive resin is laminated on both sides of a metal sheet, and in particular, it relates to a composite sheet for hot melt adhesive, in which hot melt adhesive resin is laminated on both sides of a metal sheet, and in particular, it relates to a composite sheet for hot melt adhesive, in which hot melt adhesive resin is laminated on both sides of a metal sheet. relates to a composite sheet for hot melt bonding suitable for bonding with polyolefin resins and the like.

[Prior art] Conventionally, the same or different metals (M), polyolefins (A
1, consisting of metal/polyolefin/metal/polyolefin/metal. M+/A1/lJg/Ax/M
In order to obtain a composite sheet having the structure of 3, each metal sheet and each fusible polyolefin sheet are separately rolled out, and thermally laminated by passing them through at least a pair of nip rolls, at least one of which is a heating roll. Alternatively, each metal sheet may be laminated with each polyolefin in advance.
The method used was to laminate A and Az/M3 on both sides of the metal sheet 6 again.

[Problems to be Solved by the Invention] When a composite sheet having the above-mentioned configuration is manufactured by the former method of the above-mentioned conventional methods, it is necessary to separately determine the respective unwinding tensions when unwinding each metal and each polyolefin sheet. The problem is that if wrinkles occur in any one layer, wrinkles will occur in the entire composite sheet, lowering the product yield and making it difficult to produce stable composite sheets. there were.

In addition, when manufacturing a composite sheet using the latter method described above,
Since the metal laminates Ml/Al and M3/At, which are heat-sealed to both sides of the intermediate layer metal sheet M2, are heated from the metal side, the interface A+/ux/A* with the intermediate metal sheet is heated.
If we try to improve the adhesive strength by sufficiently thermally bonding, the problem arises that the respective interfaces of M, /An and At/us are heated excessively, and the adhesive strength of the interfaces decreases. there were. On the other hand, with proper heating to maintain good adhesive strength at the interface between cap/AI and A*/M-, A, /M,
There was a problem in that the heating of the /A interface was insufficient, resulting in a decrease in adhesive strength.

Furthermore, these methods have the problem of requiring a large investment in manufacturing equipment, and although the above-mentioned method is cost-effective when a large amount of composite sheets are used, the problem of wrinkles remains. If only a small amount of composite sheet is used,
There was a problem in that the cost was very high and the problem of wrinkles remained.

[Means for Solving the Problems 1] As a result of intensive studies to solve the conventional problems, the present inventors have developed a modified polyolefin sheet in which both sides of a metal sheet are modified with an unsaturated carboxylic acid or its anhydride. By heat-sealing using a composite sheet for hot-melt adhesive laminated and continuous in the longitudinal direction, the adhesive strength is good, wrinkles do not occur, and Ml / AI / M2 / AX /
It was discovered that a composite sheet of M3 could be obtained, and the present invention was completed.

That is, 1. The present invention is characterized in that a modified polyolefin sheet modified with an unsaturated carboxylic acid or its anhydride and having a thickness of 5 to 500 μm is laminated on the outermost layer on both sides of a metal sheet having a thickness of 5 to 500 μm. The present invention provides a longitudinally continuous composite sheet for hot melt bonding.

(Al-modified polyolefin sheet) The polyolefin modified with an unsaturated carboxylic acid or its anhydride used in the present invention is usually produced by subjecting these compounds to a graft reaction with a polyolefin.

' Polyolefins The polyolefins used in the production of such modified polyolefins include ethylene homopolymer, ethylene as the main component, α-olefins other than ethylene, vinyl acetate,
Copolymers with (meth)acrylic acid and its esters, etc.
Examples include propylene homopolymers, copolymers of propylene as a main component and α-olefins other than propylene (including ethylene), and the like.

11 weeks In addition, unsaturated carboxylic acids or their anhydrides to be subjected to the craft reaction together with these polyolefins include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, citraconic acid, citraconic anhydride, itaconic acid, itaconic anhydride, etc. can be mentioned. Among these, acrylic acid and maleic anhydride are preferred, and maleic anhydride is particularly preferred.

Although a slurry method may be used as a method for causing the Graph 1 reaction with the above-mentioned raw material polyolefin, economically, a solution method or a melt-kneading method is preferable.

In the case of the melt mixing method, Henschel's raw polyolefin powder or pellet is mixed with an unsaturated carboxylic acid or its anhydride and, if necessary, a radical reaction initiator such as an organic peroxide or an azobis compound in a predetermined mixing ratio. Tri-blending is performed using a mixer or the like, or an unsaturated carboxylic acid or its anhydride and, if necessary, an initiator are dissolved in an organic solvent, sprayed onto polyolefin powder or pellets, and blended using a Henschel mixer or the like. The blended polyolefin powder or pellet is put into a mixing machine whose system is purged with nitrogen gas, such as a Banbury mixer or a double screw mixer, and heated to a temperature of 120 to 300.
The above-mentioned modified polyolefin is obtained by melt-kneading at 0.1 to 30 minutes.

Here, the amount of initiator is less than or equal to 0.1% by weight, preferably in the range from 0.001 to 0.05% by weight, based on the polyolefin. The organic peroxides used as the above-mentioned initiator include benzoyl peroxide, acetyl peroxide, di-t-butyl peroxide, t-butylperoxylaurate, dicumyl peroxide, α,α゛-bis-t- butylperoxy-p-diisopropylbenzene,
2,5-dimethyl-2,5-di-t-butylperoxyhexane, 2,5-di-t-butylperoxyhexyl,
t-butyl peroxybenzoate, n-butyl-4,
Examples include 4-bis-t-butyl peroxyvalate, octanoyl peroxide, p-menthane hydroperoxide, etc. Azobis compounds include azobisisobutyronitrile, 2.2゛-azobisf2.4
．． 4-trismethylvaleronitrile), 2.2°-azobis(2-cyclopropylprobionitrile), and the like.

What is the modified polyolefin resin referred to in the present invention? It refers to a single modified polyolefin obtained as described above or a blend of two or more thereof, or a blend of the polyolefin resin shown above and the modified polyolefin resin obtained as described above.

The amount of unsaturated carboxylic acid or its anhydride contained in the modified polyolefin thus obtained is 0.1
The range is from 3% by weight, preferably from 0.02 to 2% by weight, particularly preferably from 0.05 to 1% by weight. 0.01% by weight
If it is less than 3% by weight, sufficient adhesive strength will not be obtained, and if it exceeds 3% by weight, gel will form, etc., and sufficient adhesive strength will not be obtained.

225 Molding This modified polyolein is molded to a thickness of 5-50 Ogm by a conventional method.
, preferably into a sheet of 10 to 200 am. If the sheet thickness is less than 5111 lm, wrinkles are likely to occur and the adhesive strength becomes unstable. If the sheet thickness exceeds 500 l1 m, the sheet forming itself is easy, but the adhesion becomes unstable from the point of view of uniform heating.

Tb) Metal Sheet The metal of the metal sheet used in the present invention includes aluminum, steel, stainless steel, tinplate, copper, brass, nickel, and the like. Particularly preferred are aluminum, steel, stainless steel, and tinplate.

The thickness of this sheet is 5-500 pm, preferably 7-500 pm.
It is 30 lo 1. If it is thinner than 5 μm, wrinkles will easily occur, while if it exceeds 500 g, workability will be impaired and its uses will be limited.

(e) Lamination method Any method can be adopted to produce the composite sheet for hot-melt adhesive of the present invention, but a preferred method is, for example, laminating modified polyolefin sheets on both sides of a metal sheet. , at least one pair of nip rolls, at least one of which is a heating roll, is pressed and passed through.

A so-called thermal lamination method is employed.

In this thermal lamination method, a resin sheet that does not adhere to the modified polyolefin, a modified polyolefin sheet,
The metal sheet, the modified polyolefin sheet, and the modified polyolefin are superimposed in a positional relationship of non-adhesive resin sheets, and the temperature is higher than the melting point of the modified polyolefin, and
It is manufactured by applying heated nip rolls at a temperature below the temperature at which the resin sheet that does not adhere to the modified polyolefin is not thermally deformed, continuously laminating it under heat, and then peeling off the resin sheet that does not adhere to the modified polyolefin on both sides after the modified polyolefin is cooled and solidified.

Examples of the resin sheet used here that does not adhere to the modified polyolefin include polyethylene nonterephthalate, nylon, polyetheretherketone, polyvinylidene fluoride, tetrafluoroethylene polymer, polyimide, and the like.

Further, as long as the outermost layer of both is made of modified polyolefin, other resins etc. may be laminated in the middle.

Five grilled plates 1 In order to laminate metal sheets on both sides of the composite sheet i- for heat-melting adhesion of the present invention obtained as described above, it is necessary to laminate metal sheets, the composite sheet of the present invention, and the metal sheet. A thermal lamination method can be adopted in which the materials are laminated in sequence and the materials are pressed and passed between at least a pair of nip rolls, both of which are heating rolls.

When the melting points of the modified polyolefins on the amphoteric layer surfaces of the composite sheet for hot melt adhesive of the present invention are different, the high melting point modified polyolefin side is placed on the heating roll side between nip rolls, at least one of which is a heating roll. Passed through.

[Example] Example 1 Modified polyethylene grafted with maleic anhydride by melt cross-fertilization method (density + 0.93 g/am', MFR
: 3 g/10 minutes, maleic anhydride content: [1.06% by weight) was extruded from a spiral inflation die at an extrusion temperature of 200°C using a 50m+a extruder with L/D = 25 to obtain a modified polyethylene with a thickness of lhm. Got a sheet.

Next, polyethylene terephthalate sheet (50 μm)
/Modified polyethylene sheet obtained above-1・(1,h
m) /Aluminum metal sheet (20μm) /Modified polyethylene sheet obtained above (10un+) /
Polyethylene telelaminate sheet (50μm)
The upper layer is a 120 mm diameter silicone rubber roll, and the lower layer is a 120 n+ roll heated to 150°C.
A linear pressure of 15 kg/cm and a passing speed of 1.5 Il1 were passed between nip rolls consisting of +mφ chrome-plated metal rolls.
After the modified polyethylene was cooled and solidified, the polyethylene terephthalate sheets on both sides were continuously peeled off to obtain a continuous three-layer composite sheet for hot melt adhesive consisting of modified polyethylene/aluminum/modified polyethylene. .

5US304 metal sheets each having a thickness of 30 ura were stacked on both sides of the obtained composite sheet for hot-melt bonding, and a linear pressure of 2゜kg/
cra, laminated continuously at a passing speed of 11 minutes,
A continuous five-layer composite sheet of SOS/modified polyethylene/aluminum/modified polyethylene/SO5 was obtained.

No wrinkles were observed in the five-layer sheet obtained, and the thickness was uniform. Also, grab the SUS on both sides and
When subjected to a tensile test at a speed of 2.5 kg/1511
The adhesive strength was good at 1 m.

Example 2 A 200mm x 200mm piece was cut out from the three-layer composite sheet for thermal melt bonding of modified polyethylene/aluminum/modified polyethylene obtained in Example 1, and this was sandwiched between 5US304 sheets having the same dimensions and a thickness of 4011 Il. 60 at a temperature of ℃ and a pressure of 20 kg/e+s''
Heat fusion was performed for seconds.

Obtained SO5/modified polyethylene/aluminum/modified polyethylene: //5IJS 200+++mX 20
0nv (7) There are no wrinkles on the 5-layer sheet, the thickness is uniform, and the edges are firm.
When subjected to a tensile test at 300+u+/min, 3kg/
It had a good adhesive strength of 5 mm.

Comparative Example 1 l101lI modified polyethylene sheet used in Example 1, 2hs7 Luminilla A metal sheet, 30 μm SUS
Using 304 metal sheet and laminating equipment, SOS
/ Modified polyethylene / Aluminum / Modified polyethylene / 5US (7) 5 layers stacked, temperature 180'C, linear pressure 20
When laminated continuously at kg/cm and a passing speed of 1 ml/min, wrinkles occurred between the modified polyethylene sheet and the aluminum sheet, and a 5-layer composite sheet with a uniform thickness could not be obtained.

[Effects of the Invention J The composite sheet for hot-melt adhesion of the present invention is a laminated sheet of unsaturated carboxylic acid-modified polyolefin on both sides of a metal sheet, and this sheet can be used for hot-melt bonding between metals and for bonding metals and polyolefins. When used for hot melt bonding, excellent and uniform adhesive strength can be obtained. Particularly when manufacturing a composite sheet consisting of metal/polyolefin/metal/polyolefin/metal, the composite sheet for hot melt bonding of the present invention is used as the adhesive layer and a pair of heated nip rolls is used to produce a composite sheet with no wrinkles and a uniform thickness. Sheets can be produced continuously.

Claims (1)

[Claims] (1) A modified polyolefin sheet modified with an unsaturated carboxylic acid or its anhydride having a thickness of 5 to 500 μm is laminated to the outermost layer on both sides of a metal sheet having a thickness of 5 to 500 μm. Composite sheet for continuous hot melt bonding.