JPH09314734A - Flame retardant metal resin composite plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make peeling between metal/resin interfaces difficult in (a) metal/ resin/metal composite plate of good flame retardant and (a) metal/resin/metal composite plate. SOLUTION: In a product which is formed by bonding a metal sheet to both sides of an inorganic filler-incorporated polyolefin sheet which contains 20-45wt.% of polyolefin 150kg/cm<2> or stronger in tensile strength, 55-80wt.% of an inorganic filler of 15-90μm average particle size, and saturated fatty acid of not more than 5wt.% of the filler and has a heating value of not exceeding 14.0kJ/g, the drum peel strength of the interfaces between the metal sheet and the resin sheet is at least 100mmN/mm.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant metal resin composite plate. More specifically, the present invention relates to a flame-retardant metal-resin composite plate in which a metal sheet is bonded to both sides of a resin sheet which is filled with an inorganic filler to improve flame retardancy.

[0002]

2. Description of the Related Art A metal sheet / resin sheet composite plate (hereinafter, also simply referred to as "metal / resin composite plate") in which a metal sheet is bonded to both sides of a resin sheet has been conventionally known. A typical example is an AL sheet / resin sheet / AL in which thin aluminum (hereinafter sometimes simply referred to as AL) sheets are adhered to both sides of a polyolefin resin sheet.
It has a layered structure composed of sheets. This metal / resin /
By selecting the thickness of each sheet that composes the composite plate, the metal composite plate can be made light in weight, excellent in bending rigidity, and excellent in processing performance. Widely used in.

[0003]

A metal sheet / resin sheet / metal sheet composite plate represented by the above-mentioned AL sheet / resin sheet / AL sheet layer structure (hereinafter referred to as “metal / resin / metal composite plate” or simply "Composite plate" may have many advantages such as lightness and smoothness compared with a metal sheet of the same thickness alone, and compared with the case of using a synthetic resin sheet alone, Because of its excellent mechanical properties and flame retardancy, it is used in various applications such as building materials.

However, in the metal / resin / metal composite plate, the resin sheet is exposed at the end portion thereof, and the exposed resin sheet easily burns. Therefore, when the end portion of the sheet is ignited, The flame may reach the edges and spread the burning area. Therefore, Japanese Patent Laid-Open No. 80441/1990,
JP-A-5-245963 proposes a method in which the resin itself is made flame-retardant and the flame-retarded resin is used.

In Japanese Patent Laid-Open No. 80441/1990, 30 to 300 parts by weight of aluminum hydroxide having an average particle diameter of 3 μm or less adsorbed with a specific inorganic compound is mixed and kneaded with 100 parts by weight of a polyolefin resin. Describes the invention of a polyolefin resin composition having flame retardancy. When a resin sheet made of this flame-retardant polyolefin-based resin composition is used as an intermediate layer of a metal / resin / metal composite plate, the metal / resin drum peel peel strength becomes low, and this composite plate is processed into an end use. In this case, there is a drawback that the metal / resin interface is easily peeled off.

In JP-A-5-245963, a polyolefin resin is foamed at a foaming ratio of 1.1 to 3.0 to form a foamed resin layer, and a resin layer which is not foamed is laminated on both sides. The invention of a flame-retardant composite material in which a metal sheet is joined to both surfaces of a sheet having a three-layer structure is described. However, this composite plate also has a drawback that the metal / resin drum peel peel strength is low and the metal / resin interface is easily peeled off.

The present invention has been made in order to improve the above-mentioned various defects existing in the conventional metal / resin / metal composite plate, and has the following objects. 1. Provided is a metal / resin / metal composite plate having excellent flame retardancy. 2. Provided is a metal / resin / metal composite plate, wherein the metal / resin interface is less likely to peel off.

[0008]

In order to achieve the above object, the present invention provides ²⁰ to 45% by weight of a polyolefin resin having a tensile breaking strength of 150 kg / cm ² or more and an average particle size of 15 to 90-80 μm of inorganic filler
% By weight, saturated fatty acid 0.05 to inorganic filler
A metal sheet is bonded to both surfaces of an inorganic filler-filled polyolefin resin sheet containing 5.0 wt% or less and a combustion heat value of 14.0 kJ / g or less. A flame-retardant metal-resin composite plate having a drum peel peel strength of 100 mmN / mm or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The resin sheet constituting the composite plate according to the present invention is a polyolefin resin sheet and forms an intermediate layer of the composite plate. Examples of the polyolefin resin include α-olefins such as polyethylene, polypropylene and polybutene, and ethylene copolymers such as ethylene propylene copolymer and ethylene vinyl acetate copolymer. These may be used alone or as a mixture of two or more.

The above polyolefin resin must have a tensile breaking strength of 150 kg / cm ² or more. When the tensile strength at break is less than 150 kg / cm ^2, it is not preferable because the peel strength of the metal / resin drum peel is not improved when it is used for metal / resin / metal composite plate.

In the resin sheet constituting the composite plate, the above polyolefin resin is mixed with an inorganic filler.
The inorganic filler functions to improve the flame retardancy of the polyolefin-based resin and reduce the heat value of combustion. As inorganic fillers, in addition to calcium carbonate, talc, etc.,
Examples thereof include hydrated metal oxides such as aluminum hydroxide, magnesium hydroxide and calcium hydroxide.

The inorganic filler has an average particle size of 15 to 90.
It is necessary to use the one of μm. When the average particle diameter of the inorganic filler is less than 15 μm, the drum peel peel strength from the metal sheet is 100 mmN / mm or less, and when the average particle diameter exceeds 90 μm, the flame retardancy tends to be insufficient, and both Not preferable. The inorganic filler is
Particularly preferable range of the average particle diameter is 15 to 6
0 μm.

The blending amount of the inorganic filler with respect to the polyolefin resin must be in the range of 55 to 80% by weight. When the content of the inorganic filler is less than 55% by weight,
The combustion heat value of the thermoplastic resin sheet filled with inorganic filler is 1
Since it exceeds 4.0 kJ / g, flame retardancy becomes insufficient,
If it exceeds 80% by weight, the drum peel peel strength from the metal sheet becomes 100 mmN / mm or less, and the extrusion processing performance tends to deteriorate, either of which is not preferable.

The resin sheet forming the composite plate further includes
It is preferable to add a saturated fatty acid. The saturated fatty acid functions to prevent an increase in melt viscosity of the inorganic filler-filled thermoplastic resin sheet and to improve extrusion processing performance.
Examples of saturated fatty acids include stearic acid, butyric acid, oleic acid, and metal salts thereof. It is necessary that the amount of the saturated fatty acid added be 5% by weight or less based on the inorganic filler. If the added amount exceeds 5% by weight,
Drum peeling strength from metal sheet is 100mmN / mm
The following tends to occur, which is not preferable. A particularly preferable range of the amount of the saturated fatty acid added is 0.1 to 3.0% by weight.

The resin sheet constituting the composite plate is required to have a calorific value of combustion of 14.0 kJ / g or less. When the heat value of combustion exceeds 14.0 kJ / g, the resin sheet becomes inferior in flame retardance, which is not preferable. The amount of heat generated by combustion of the resin sheet can be adjusted by the type and amount of the inorganic filler compounded in the resin for the resin sheet raw material.

To produce a resin sheet, a polyolefin resin may be weighed and blended with a predetermined amount of an inorganic filler and a saturated fatty acid, melt-kneaded with an extruder, and extruded into a sheet. The mixing order of the resin and the compound is not particularly limited. The three components may be mixed together, or an inorganic filler and a saturated fatty acid may be mixed in advance and the mixture may be mixed with the resin. A conventionally known mixer can be used to mix the inorganic filler and the saturated fatty acid into the polyolefin resin. The mixer may have either a structure in which the container itself rotates slowly, or a structure in which a screw or a rotary blade rotates in a fixed container. The former includes a ball mill, a pebble mill, a tumbling mixer and the like, and the latter includes a ribbon mixer, a change can mixer, a mixer, a super mixer (Henschel mixer), a lei crusher and the like.

The extruder used for producing the resin sheet may be either a single-screw extruder or a multi-screw extruder. When these extruders are vent type extruders, the volatile components contained in the molten resin can be forcibly volatilized to prevent bubbles from remaining in the resin sheet layer, and a resin sheet having a smooth surface can be formed. Obtainable. The thickness of the obtained inorganic filler-filled polyolefin resin sheet is preferably 2 to 8 mm. If the thickness is less than 2 mm, the thickness of the product composite plate becomes too thin, and the metal sheet must be made thick to increase the thickness of the product composite plate, which is not preferable because the product composite plate becomes heavy. If the thickness exceeds 8 mm, it will be difficult to bend the product composite board,
In addition, at that time, a defect such as separation of the metal / resin interface occurs, which is not preferable.

The metal sheets that make up the composite plate form the outer surface of the composite plate. As the metal forming the metal sheet,
Examples thereof include titanium, aluminum (including alloy), stainless steel, iron and the like. The metal sheet has a thickness of 0.
It is preferable to select in the range of 1 to 0.8 mm. If the thickness of the metal sheet is less than 0.1 mm, the mechanical strength of the composite plate will be insufficient, and if it exceeds 0.8 mm, the workability at the time of bending the composite plate will be poor, both of which are not preferable.

In order to laminate a resin sheet and a metal sheet into a composite plate, the laminated surface of the metal sheet is degreased with a solvent, detergent, etc., and then roughened by shot blasting and / or chemical etching. It is preferable to apply a coating or a primer. The anchoring effect can be improved at the laminated interface by applying these surface roughening treatment and the undercoating agent. When the chemical etching method is used, an etching solution is used. Since the etching solution varies depending on the type of metal, it is possible to select from conventionally known etching solutions for each metal. Since the preferable undercoating agent also differs depending on the type of metal, it is possible to select from the conventionally known undercoating agents for each metal.

The resin sheet and the metal sheet can be laminated by a conventional method. For example, the etching surfaces of the two metal sheets may be opposed to each other, and the resin sheet may be sandwiched between them with or without the adhesive film interposed therebetween, and heating and pressing may be performed. The two metal sheets do not have to be of the same type and may be a combination of different types. The adhesive film is preferably a film that exhibits hot-melt properties, and contains ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, atactic polypropylene, polyisobutylene, etc. as the main components, and a rosin-based adhesive as a tackifier. Examples include films formed by blending resins and petroleum-based resins. The adhesive strength can be adjusted by the type of main component resin, the type and amount of tackifier, and the type and amount of other plasticizer, filler, and the like.

The composite plate according to the present invention has a drum peel peel strength of 100 mmN at the interface between the metal sheet and the resin sheet.
/ Mm or more is required. If the drum peel peel strength is less than 100 mmN / mm, peeling is likely to occur at the interface between the resin sheet and the metal sheet when bending the composite plate, which is not preferable. "Drum peel peel strength" in the present invention
Means a value measured according to ASTM D1781.

The flame-retardant metal / resin composite plate according to the present invention is as described above, has good flame retardancy, and has a drum peel peel strength at the interface between the metal sheet and the resin sheet. It is high and has excellent bending workability.
INDUSTRIAL APPLICABILITY The composite plate according to the present invention is suitable for applications such as an inner wall, an outer wall of a building and a signboard.

[0023]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the following examples as long as the gist thereof is not exceeded. In the examples described below, the melt viscosity of the resin composition for resin sheet, the calorific value of combustion, and various performances of the composite sheet composed of metal sheet / resin sheet / metal sheet were evaluated by the methods described below. It is a thing.

(1) Measurement of Melt Viscosity A resin sheet is cut into pellets, and the pellets are tested at a test temperature of 180 ° C. according to JIS K7199.
The viscosity is measured at a shear rate of 100 sec ^-1 . (2) Drum peel peel strength measurement A test piece having a width of 60 mm and a length of 200 mm was cut out from the obtained metal / resin / metal composite plate, and this was cut according to ASTM D17.
It was subjected to a drum peel peel strength test in accordance with No. 81 and measured.

(3) Flame-retardant performance test From the obtained metal / resin / metal composite plate, a test piece having a vertical and horizontal length of 220 mm was cut out, and this was cut to JIS A1.
A flame-retardant performance test (additional test defined in Section 4.) conforming to 321 was performed and the measurement was performed. (4) Combustion calorific value measurement Combustion calorific value measurement was carried out on the obtained resin sheet in accordance with ASTM D2015. The measured values are shown in SI units.

(5) Bending performance test A test piece having a width of 180 mm and a length of 240 mm was cut out from the obtained metal / resin / metal composite plate, and this was cut using a press brake at 60R, 50R, 40R, ... Bending processing perpendicular to the rolling direction of the metal sheet is performed to pull the metal sheet
The critical bending R (radius of curvature) at which no fracture occurs in the composite plate, such as compression fracture, buckling, and buckling of the resin sheet, was measured.

[Examples 1 to 7, Comparative Examples 1 to 5] 1. Materials used (1) Metal sheet An aluminum sheet having a thickness of 0.5 mm was used. (2) Adhesive film An ethylene / acrylic acid copolymer film having a thickness of 40 μm was used.

(3) Raw material resin for resin sheet As shown in Table 1, low density polyethylene and high density polyethylene having different tensile fracture strengths are used, and they are shown by the following abbreviations. In addition, MFR means the melt flow rate measured based on JISK6760 here, and tensile fracture strength is the raw material resin for resin sheets, and the tensile test method based on JISK6760 WHEREIN: At the moment the test piece fracture | ruptured. It means tensile stress value. LF320H; LDPE, MFR = 1.1 g / 10 min, tensile breaking strength 180 kg / cm ² , density 0.924 g / cm ³ , Mitsubishi Chemical LF542M; LDPE, MFR-4.0 g / 10 min, tensile breaking strength 150 kg / Cm ² , density 0.925 g / cm ³ , Mitsubishi Chemical Forest LF660H; LDPE, MFR = 7.0 g / 10 min, tensile fracture strength 135 kg / cm ² , density 0.927 g / cm ³ ,
Mitsubishi Kagaku-Mori HJ580; HDPE, MFR = 11.0g / 10min, tensile fracture strength 180kg / cm ² , density 0.960g / cm ³ , Mitsubishi Kagaku-Mori

(4) Inorganic filler As shown in Table 1, aluminum hydroxide and magnesium hydroxide, which are hydrated metal oxides having different average particle diameters, are used. Indicated by. The average particle size of the inorganic filler means the particle size at which the cumulative frequency is 50% when measured by Microtrac. A: Aluminum hydroxide, average particle diameter 85 μm, made by Alcoa Kasei Mori B: Aluminum hydroxide, average particle diameter 60 μm, made by Alcoa Kasei Mori C: Aluminum hydroxide, average particle diameter 25 μm, made by Alcoa Kasei Mori D; Aluminum hydroxide , Average particle diameter 8 μm, manufactured by Alcoa Kasei E; aluminum hydroxide, average particle diameter 1 μm, manufactured by Alcoa Kasei F; magnesium hydroxide, average particle diameter 50 μm, manufactured by Wandou Kogyo

(5) Saturated fatty acid Stearic acid (manufactured by NOF CORPORATION, trade name: Sakura beef tallow stearic acid) was used.

2. Preparation of metal sheet Metal plate (aluminum sheet) in all examples
After being washed with water, the oil and fat adhering during rolling was removed by immersing in a degreasing liquid, further washed with hot water and then dried. A surface treatment (about 50 mg / m ^{2 in} terms of chromium) of a coating type chromium chromate solution was applied to the adhesive surface side with the resin sheet, and the adhesive film was previously heat-sealed at 200 ° C. using a heat roll.

3. Method for producing metal / resin / metal composite plate Using three raw material supply feeders, low density polyethylene,
High-density polyethylene, aluminum hydroxide, magnesium hydroxide, and stearic acid at the ratios shown in Table 1, respectively, by a batch feed method, using a twin-screw kneader (TEM).
No. 75-BS, manufactured by Toshiba Machine Co., Ltd.), melt-kneaded with an extruder, and extruded into a sheet having a thickness of 3.0 mm. Then, on both sides of the obtained sheet, an aluminum sheet having a thickness of 0.5 mm on which an adhesive film is heat-sealed in advance is disposed, and a pressure bonding roll (diameter 200
mm, width 1300 mm, clearance 4.0 mm),
A metal / resin / metal composite plate with a total thickness of 4.0 mm was produced.

4. Evaluation of physical properties For the obtained resin sheet and metal / resin / metal composite plate,
Various evaluation tests were conducted by the method described above. The results are shown in Table 1 below.

[0034]

[Table 1]

From Table 1, the following is clear. (1) As for the raw material resin for the resin sheet, Comparative Example 3 having a tensile fracture strength of less than 150 kg / cm ² is inferior in drum peel peel strength and bending workability. (2) With respect to the average particle size of the inorganic filler blended in the resin, Comparative Example 4 and Comparative Example 5 having an average particle size of less than 15 μm are inferior in drum peel peel strength and bending workability. (3) As for the blending amount of the inorganic filler blended with the resin, Comparative Example 2 in which the blending amount is less than 55% by weight has a long afterflame time and is easily burned, and has a combustion calorific value of 14.0 KJ / g or more. Is.

(4) Example 3 in which a saturated fatty acid is blended in the resin composition for a resin sheet is Example 4 in which it is not blended.
It can be seen that the melt viscosity is lower than that of the above and the extrusion processability is improved. (5) With respect to the drum peel peel strength, the values of the other comparative examples except the comparative example 2 are not more than the value specified in claim 1. (6) In terms of flame retardancy, both Comparative Examples except Example and Comparative Example 2 have excellent flame retardancy, but Comparative Example 2 is inferior in flame retardancy.

(7) In terms of bending workability, considering that it is usually sufficient as a building wall material or the like to have a bending workability of about 60R, Examples 1 to 7,
It can be said that Comparative Examples 1 to 3 have good bending workability. (8) With respect to the combustion heat generation amount, both of the example and the comparative example other than the comparative example 2 are 14.0 kJ / g or less. When the combustion heat value is 14.0 kJ / g or more,
Inferior in flame retardancy (see Comparative Example 2). (9) On the other hand, the composite plates of Examples 1 to 7 have high drum peel peel strength, excellent flame retardancy, and excellent bending workability.

[0038]

The present invention has the following particularly advantageous effects, and its industrial value is extremely large. 1. In the metal / resin / metal composite plate according to the present invention, the inorganic filler-filled polyolefin-based resin sheet layer forming the intermediate layer is blended with a specific amount of an inorganic filler having a specific average particle diameter, and thus metal / resin / metal. Even if the resin sheet exposed at the end of the composite plate is ignited, the flame is less likely to propagate through the end and exhibits excellent flame retardancy. 2. The metal / resin / metal composite plate according to the present invention exhibits excellent flame retardancy, since the inorganic filler-filled polyolefin-based resin sheet layer constituting the intermediate layer has a combustion heat value of 14.0 kJ / g or less. 3. The metal / resin / metal composite plate according to the present invention has a drum peel peel strength of 100 mmN between the metal sheet and the resin sheet.
/ Mm or more, it is difficult to peel the metal / resin interface,
Excellent bending workability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B32B 27/20 B32B 27/20 Z

Claims (5)

[Claims] 1. A polyolefin resin having a tensile breaking strength of 150 kg / cm ² or more, ²⁰ to 45% by weight, an inorganic filler having an average particle diameter of 15 to 90 μm, 55 to 80% by weight, and a saturated fatty acid with respect to the inorganic filler. 0.05-5.
Contains less than 0% by weight and has a combustion calorific value of 1
A metal sheet is joined to both surfaces of an inorganic filler-filled polyolefin resin sheet having a pressure of 4.0 kJ / g or less, and the drum peel peel strength between the metal sheet and the resin sheet is 100 mmN / mm or more. Flame-retardant metal resin composite board. 2. The flame-retardant metal-resin composite plate according to claim 1, wherein the amount of saturated fatty acid relative to the inorganic filler is 0.1 to 3.0% by weight. 3. The thickness of the polyolefin resin sheet is 2
The flame-retardant metal-resin composite plate according to claim 1 or 2, wherein one metal sheet has a thickness of 0.1 to 0.8 mm. 4. The flame-retardant property according to claim 1, wherein the metal sheet is a sheet of one or two metals selected from titanium, aluminum, stainless steel and iron. Metal-resin composite board. 5. The flame-retardant metal-resin composite plate according to claim 1, wherein the inorganic filler is aluminum hydroxide.