JPS63242535A - Metal-polypropylene-metal laminated composite body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal/resin laminated composite in which a polypropylene sheet is sandwiched between metal plates and pressure bonded.

More specifically, polypropylene fibers obtained from modified polypropylene obtained by modifying crystalline polypropylene with an unsaturated carboxylic acid or a derivative thereof, or crystalline polypropylene containing the modified polypropylene, and a specific amount of 1A type II miscellaneous are irregularly entangled. A polypropylene sheet (hereinafter referred to as core material) obtained by spraying a specific meter of conductive filler with a specific particle size range onto the formed nonwoven fabric and heating and compressing it.
and a laminated composite composed of metal plates.

[Conventional technology]

In recent years, from the viewpoints of reducing the weight of metal plates, imparting sound-absorbing properties, reducing nobleness, and imparting heat-insulating properties to metal plates, laminated composites in which Plasdec sheets are sandwiched between metal plates have been developed, and are used in civil engineering, It is widely used in the fields of architecture, private cars, home appliances, etc.

Conventionally, thermoplastic resins such as polyethylene, polypropylene, and nylon-6 have been used as plastic sheets used as core materials.

The core material is also conductive! In order to enable welding as a composite, metal powder, carbon black,
Kneading metal-plated resin powder and the like is also practiced.

[Problem that the invention aims to solve]

A composite material having a polypropylene sheet as the core I is required to have adhesive strength that can withstand secondary processing such as bending, punching, cutting, and deep drawing.

In conventional laminated composites using polypropylene resin as the core material, baking when painting molded parts is caused by punching during treatment (usually heat treated at 180 to 200°C for 30 minutes). The resin may melt and flow out from the exposed area, or dripping of molten resin (hereinafter referred to as dripping)
This occurs and blocks the punched area, causing problems in post-processing, and the molten resin shrinks significantly during the cooling and solidification process, causing deformation, especially around the punched area, and the core resin. There are drawbacks such as peeling at the interface between the metal and the surface of the paint, and the problem is that baking cannot be used for parts that require a painting process.

Furthermore, since polypropylene resin is an insulator, it also has the problem that electric welding such as spot welding and seam welding cannot be performed.

In order to make the resin conductive in order to enable welding, there is a method of kneading metal powder into the resin, but it is difficult to mix uniformly and there are equipment problems such as extrusion screws wearing out. There was a point. Furthermore, if the metal particles are not filled too much, the electrical connection between the metal particles tends to be incomplete, and weldability is not necessarily perfect.

Therefore, the object of the present invention is to have a high adhesive strength that is essential for secondary processing, to prevent molten resin from flowing out or dropping during the processing process, and to prevent thermal deformation near the cut part. An object of the present invention is to provide a metal/polypropylene/metal laminated composite that has heat resistance that prevents peeling between a core resin and a metal plate and can be electrically resistance welded.

[Means for solving problems]

As a result of extensive studies to solve the above-mentioned problems, the present inventors created a nonwoven fabric using specific modified propylene fibers and molar fibers, and sprinkled a conductive filler with a specific particle size range on it. The inventors discovered that the problem could be solved by using a core material that was heated and thermocompressed, and the present invention was completed.

That is, the present invention provides polypropylene fibers obtained from modified propylene obtained by modifying crystalline polypropylene with an unsaturated carboxylic acid or its vt derivative, or from crystalline polypropylene mixed with the modified polypropylene.
A conductive filler is sprinkled on a nonwoven fabric formed by irregularly intertwining 15% to 50% of organic fibers with 5% to 40% by weight of a conductive filler based on the weight of the nonwoven fabric, and then A polypropylene sheet obtained by heating and compressing at a temperature of ■≦R≦T+0.0
5 (m*), and the polypropylene sheet is used as a core material.
It is a polypropylene/metal laminated composite.

The modified polypropylene used in the present invention is a crystalline polypropylene described below modified with an unsaturated carboxylic acid or a derivative thereof.

Examples of unsaturated carboxylic acids used in the production of the modified polypropylene 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, acrylic
lQm[Puru, ethyl methacrylate, butyl acrylate, methyl methacrylate, glycidyl acrylate, glycidyl methacrylate, monomethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, monomethyl itaconate, itacon Acid diethyl ester, acrylamide, methacrylamide, maleic monoamide, maleic diamide, maleic M-N-monoedylamide, maleic l1fi-N.

N-diethylamide, maleimide, N-pudylmaleimide, N-phenylmaleimide, sodium acrylate,
Examples include sodium methacrylate and potassium acrylate. It is preferable to use maleic anhydride.

Various known methods can be employed as the modification method. For example, it is carried out by melt-kneading crystalline polypropylene and an unsaturated carboxylic acid or its derivative at a temperature equal to or higher than the melting point of the crystalline polypropylene in the presence of an organic peroxide.

The amount of the unsaturated carboxylic acid or its derivative used is 0.01 to 5% based on the crystalline polypropylene that is the raw material resin.
% by weight, more preferably 0.05-3% by weight. In addition, in the present invention, the modified polypropylene of
A mixture of unmodified crystalline polypropylene containing frm% or more can be used. Generally, the m of unsaturated carboxylic acid or its derivative used is 0.1 to
It is preferable to use 10 fJM% modified polypropylene mixed with unmodified crystalline polypropylene at the above-mentioned ratio.

The crystalline polypropylene used in the modified polypropylene and the crystalline polypropylene used mixed with the modified polypropylene include propylene homopolymers, propylene-ethylene block copolymers or random copolymers containing at least 70% by weight of propylene components. , a propylene/ethylene/butene-1 block copolymer or random copolymer, a propylene/butene-1 random copolymer, and a mixture of two or more thereof.

The crystalline polypropylene for the modified boria 0 pyrene and the crystalline polypropylene mixed with the modified polypropylene may be of the same type or may be of different types. Also, the melt flow rate is 0.1 to 20! ? /1
About 0 minutes is preferable, more preferably 0.5 to 1
This is the 09/10 b.

The modified polypropylene used in the present invention or the crystalline polypropylene containing the modified polypropylene may be mixed with ethylene propylene rubber, ethylene propylene diene rubber, poly4-methylpentene, brene acid-resistant vinyl copolymer, etc. .

By modifying crystalline polypropylene with an unsaturated carboxylic acid or its derivative, or by mixing a modified resin, the adhesion between the core material and metal when a boria-n-pyrene sheet obtained from this is used as a core material. can be improved.

The modified polypropylene or the crystalline polypropylene containing the modified polypropylene may contain heat-resistant stabilizers, weather-resistant stabilizers, erasing agents, slip agents,
A flame retardant, an antistatic agent, a nucleating agent, an inorganic filler, etc. may be mixed and used.

The organic fibers used in the present invention include the aiai
There are no particular restrictions on the use of nonwoven fabrics, other than those that do not decompose or melt under the temperature conditions during melt compression or molding of a nonwoven fabric formed from polypropylene fibers and polypropylene fibers, such as polyamide fibers and polyimide fibers. , polyester m navy blue, polyvinyl alcohol uni, polyvinylidene chloride fiber, polyacrylonitrile tan,
Examples include polyurethane fibers, phenolic fibers, rayon fibers, acetate mm, cotton fibers, flax fibers, jute fibers, wool II, silk fibers, and mixtures of two or more of these fibers.

The nonwoven fabric used in the present invention can be obtained by a binder method, a needle punching method, a hydraulic entanglement method using spunbonding, a thermal bonding method, a wet papermaking method, or the like.

The proportion of the organic tar strip and the conductive fibers in the nonwoven fabric used in the present invention is preferably within the range of 15 to 50%, particularly preferably 20 to 40%.

If the organic fiber content exceeds 50% by weight, it is not preferable because the adhesive strength of the resulting LA layer composite decreases;
If it is less than % by weight, baking during painting is not preferable because the molten resin will flow out from the cut or punched parts during processing and the interface between the resin and the metal plate will easily peel off.

Next, the conductive filler used in the present invention includes metals such as gold, silver, copper, iron, tin, lead, zinc, aluminum, nickel, and titanium, and alloys containing one or more of these as main components; Furthermore, the surface of a synthetic resin, ceramic, or inorganic filler is coated with metal, and the shape thereof is preferably spherical, granular, or angular.

The particle size range of the conductive filler is 0.03~0.5sg+
It is preferably about 0.05 to 0.3, more preferably 0.05 to 0.3.
It is in the range of sm. The particle size (R) of the 117i filler was determined from the weight per unit area of the core polypropylene sheet and the density. ! Thickness (T) and T≦R
It is necessary to select and use the range such that ≦T+0.05 (am).

If the particle size of the conductive filler is smaller than the film thickness of the polypropylene sheet, it will be difficult to obtain conductivity between the two metal plates;
If a conductive filler with a particle size exceeding 0.05 sm is used, the adhesive strength between the metal and the core material will decrease when a laminated composite is formed, which is not preferable.

NU determined from the particle size of the conductive filler, weight and density per unit area of the polypropylene sheet containing it
By regulating the relationship between the two metal plates as described above, it is possible to easily create a state in which the conductive filler is in contact with both of the two metal plates of the laminated composite.

The amount of the conductive filler to be blended is preferably in the range of 5 to 40% by weight, particularly preferably 7 to 30% by weight, based on the basis weight of the nonwoven fabric. If the content of the conductive filler is less than 5%, the conductivity in the thickness direction of the obtained product w1 composite will be poor, making electrical resistance welding difficult. This is not preferable because the peel strength decreases significantly during the process, narrowing the conditions for secondary processing, and making it difficult to produce polypropylene sheets.

The polypropylene sheet 1- used as the core material of the present invention is formed into a sheet by heating and compressing the above-mentioned nonwoven fabric using a device such as a super calender at a temperature higher than the melting point of the polypropylene mm, Thickness is 0.03 ~
It is desirable that it be within the range of 0.5sm+, preferably 0.05 to 0.3s.

A sheet obtained by heating and compressing a nonwoven fabric according to the present invention has a lower temperature than a sheet obtained by extrusion or calendaring.
By reducing the thickness, it is possible to obtain a sheet with a thickness of 100 μm or less.

The metal plates used in the present invention include metal plates made of iron, steel, aluminum, copper, zinc, tin, nickel, titanium, etc., and metal plates made of alloys containing one or more of these metals as main components. I can do it.

The thickness of the metal plate is 0.05 to 2.0all11. Preferably it is 0.15-1.011M.

The adhesive surface of the metal plate is usually degreased or sandblasted]! I! It is used after surface treatment such as Furthermore, a primer treatment such as an epoxy resin coating or a surface treatment such as a chromate treatment may be performed.

The laminated composite of the present invention is obtained by laminating metal plates with surface-treated adhesive surfaces on both sides of the polypropylene sheet, and then
It can be obtained by heat-pressing using a compression molding machine, a hot roller, or the like.

The heating temperature at this time is preferably 160 to 220°C, and the pressure is preferably within the range of 1 to 50 Ky/ciG, and the bonding is carried out for 0.1 seconds to 10 minutes under these conditions. This is desirable.

[For production]

Polypropylene does not have polar groups, so even if various surface treatments are applied to the surface of the metal plate, the adhesive strength after pressure bonding is weak. Therefore, polar groups are introduced, and the composite has adhesive strength that can withstand various secondary processes.

A nonwoven fabric is made from modified polypropylene M navy blue and organic material 1 liff, and polypropylene! ! A sheet heated and compressed at a temperature higher than the melting point of the resin was used as a core material and a metal plate was crimped onto it, so it became a resin core material reinforced by the network structure of right N13 fibers, and when processed as a composite, it would not be baked on. The molten polypropylene is incorporated into the reticulated organic fibers, so there is no run-off or drop-off from the processing area, no thermal deformation near the cut area, no peeling between the resin and the metal plate, and good heat resistance.

Further, normally, conductive fillers tend to aggregate and are difficult to knead uniformly, but in the present invention, since the conductive fillers are dispersed in the form of a nonwoven fabric, uniform distribution can be obtained without special kneading. Moreover, the filler particle size R is relative to the sheet film thickness ■
Since the range is selected such that ≦R<T+0.05 (m 2 ), conductivity between both metal plates can be ensured when the metal plates are hot-pressed, and weldability is improved.

〔Example〕

The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited to the same extent by the Examples.

(Example 1.2, Comparative Examples 1 to 4) A propylene/ethylene random copolymer containing ethylene containing PA of 3.5 Jffi% was used as a radical initiator at 1°3 (t
-butylperoxyisopropyl) bempine 0.10f
25% heavy chain of modified polypropylene modified with 1.2% by weight of maleic anhydride using filfi% and unmodified propylene/ethylene block copolymer (ethylene content 8.5%).
Polypropylene consisting of 60[i% (1ii1%)] and 15% by weight of ethylene-propylene rubber was processed into fibers. The fiber and bouylon fiber N (fiber length 50 M) were first
Mixed in the proportions shown in the table! ! Particle size 0.088 on a nonwoven fabric with a fabric weight of 180 g/rd made from a miscellaneous mixture
~0.10/1M iron alloy powder was sprinkled at the ratio shown in Table 1, and then pressed at a linear pressure of 3ONy/set and a temperature of 190°C using a test super calendar and infrared heating to form a sheet. did.

Next, the surface was cleaned with triclean as a metal plate to a thickness of 0.2
A 7jw+ cold rolled steel plate was prepared.

The sheet was inserted between two steel plates and pressed together using a hot press at 180° C. for 1 minute at a pressure of 20 Ky/1ylG to obtain a laminated composite.

The T-peel strength, electrical resistance in the thickness direction, and state after heat treatment of the laminated composite were evaluated and observed, and the results are shown in Table 1.

Incidentally, the measurement of type 1 peel strength was carried out according to JIS-6854.

However, the tensile speed was 200 am/min. In addition, the electrical resistance in the thickness direction was measured using a 21mm Buting Digital Multimeter TR6877 (
(manufactured by Takeda Uken). Also, heat treatment is 1Ii20n,
A diameter of 20s is placed in the center of the laminated composite cut into 10cm width pieces.
The specimen in which the hole was drilled was used as a test piece, and the test piece was suspended in a heating oven kept at 200°C for 30 minutes.

As shown in Table 1, the V4-layer composite of the present invention, which uses a polypropylene sheet containing organic fibers and conductive fillers in a specific proportion as the core I, has high peel strength and can be easily removed from the cut portion by heat treatment. No outflow of molten resin was observed, and there was no deformation of the cut portion. Furthermore, no peeling phenomenon between the metal plate and the resin layer at the cut portion was observed, and the laminated composite maintained its shape before heat treatment. Additionally, the laminated composites of the present invention exhibit low resistance values that allow electrical resistance welding.

On the other hand, in Comparative Example 1, which does not contain iron alloy powder, the electrical resistance in the thickness direction is greater than 1012Ω, and it cannot be used for welding. Comparative Example 2 in which the amount of iron alloy powder is larger than the range of the present invention
In this case, the T-type peel strength is weak, and it is hot ground yI! Peeling after the cut was also observed. In Comparative Example 3, in which the proportion of nylon m-miscellaneous was less than the range of the present invention, flow of resin during heat treatment and slight deformation of the cut portion were observed. In addition, in Comparative Example 4 in which neither nylon fiber nor iron alloy powder was blended, the electrical resistance in the thickness direction was also large, and flow of the resin after heat treatment, deformation of the cut portion, and peeling were also observed.

In Comparative Example 5, unmodified polypropylene! &1180
A nonwoven fabric is formed from 2°0 weight% of nylon fibers, and the nonwoven fabric has a mesh width of 10! An attempt was made to produce a laminated composite in the same manner as in Example 1 by scattering nffi% iron alloy powder, but a VI layer composite could not be obtained due to the adhesive strength between polypropylene and metal.

(Example 3.4, Comparative Example 5.6) Using a propylene/ethylene block copolymer with an ethylene content of 7.0% as a radical initiator, 1.3bis(t-butylperoxyisopropylbenzene>0.08% by weight 25% by weight of modified polypropylene modified with 0.8% by weight of crystalline anhydrous maleic maleic M (NOF) and 60% by weight of unmodified propylene/ethylene block copolymer (ethylene content 8.5% by weight) % and 15 fflff 1% of ethylene propylene rubber was processed into fibers.

A nonwoven fabric having a basis weight as shown in Table 2 was produced from a fiber II mixture of the 11 spools (70% by weight) and Cotton Woven 1 (30% by weight). Next, conductive filler (nickel powder, particle size range 0.105 to 0.124 m) is sprinkled on each nonwoven fabric at a rate of 10% by weight per weight of each nonwoven fabric,
Then, using a super calender for testing and infrared heating in combination, it was pressed at a linear pressure of 20 and a 9/Cd1 temperature of 200°C, and cooled to form a sheet.

The sheet was sandwiched between the same metal plates as used in Example 1.2 and pressed using a hot press at 200° C. for 1 minute at a pressure of 20 to 9/ai to obtain a laminated composite plate. - The T-peel strength, electrical resistance in the thickness direction, and state after σ heat treatment of the $141FI composite were evaluated and observed in accordance with Example 1.2, and the results are shown in Table 2.

As shown in Table 2, the laminated composite of the present invention has strong adhesive strength that can withstand secondary processing, and does not receive any compensation even after heat treatment. Furthermore, it exhibits a low resistance value that allows electric resistance welding.

In Comparative Example 6, in which the minimum particle size of the conductive filler was larger than the value obtained by adding 0.05 am to the sheet thickness, the T-peel strength was weak, and peeling in the bright areas after heat treatment was observed. Furthermore, in Comparative Example 7, in which the sheet thickness was 3' larger than the maximum particle size of the filler, the electrical resistance in the thickness direction was greater than 10120, and it was found that it could not be used for electric resistance welding.

〔Effect of the invention〕

The laminated composite obtained by the present invention has strong adhesive strength, and does not peel off even during secondary processing such as cutting, punching, bending, and deep drawing. In addition, there is no flow of resin from the cut surface of the cut section or punched section, there is no dropout, there is extremely little deformation due to heat, and there is no peeling between the metal plate and the core material at the cut section. can not see. Additionally, electric resistance welding, which was previously impossible, became possible. In particular, since the laminated composite of the present invention uses a nonwoven fabric heated and compressed into a sheet as a core material, it is possible to reduce the thickness of the core material to 100μ or less, and V4 using such a thin core material
The layer composite is particularly useful as a damping plate.

Therefore, it can be suitably used in a wide range of applications, such as interior and exterior panels of automobiles, various panels for home appliances and light electrical appliances, and panels for construction.

Claims (1)

[Claims] 85 to 50% by weight of polypropylene fibers obtained from modified polypropylene obtained by modifying crystalline polypropylene with an unsaturated carboxylic acid or a derivative thereof, or crystalline polypropylene mixed with the modified polypropylene, and 15 to 50% by weight of organic fibers are irregular. A polypropylene sheet obtained by dispersing conductive filler in an amount of 5 to 40% by weight based on the basis weight of the nonwoven fabric on a nonwoven fabric formed by intertwining with the fibers, and then heating and compressing it at a temperature equal to or higher than the melting point of the polypropylene fiber. and the particle size (R) of the conductive filler
When the film thickness determined from the weight and density per unit area of the sheet is (T), the relationship is T≦R≦T+0.05 (mm), and the polypropylene sheet is used as a core material. Metals, polypropylene,
Metal laminated composite.