JPS62220331A - Metal-polypropylene laminated composite body having improvedheat resistance - 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 (Industrial Application Field) The present invention is a method of filling modified polypropylene obtained by modifying crystalline polypropylene with an unsaturated carboxylic acid or a derivative thereof, or crystalline polypropylene containing the modified polypropylene at a high concentration with waste paper. The present invention relates to a laminated composite composed of a polypropylene sheet (hereinafter referred to as a core material) and a metal plate.

In recent years, metal plates have been made lighter, have sound absorption properties, vibration damping properties,
Laminated composites made by combining metal plates and plastic sheets have been developed from the perspective of providing heat insulation properties, and are widely used in the fields of civil engineering, architecture, automobiles, home appliances, etc.

(Conventional technology and its problems) Some laminated composites using polypropylene resin as the core material have been put into practical use, but baking when painting molded parts must be treated (usually at a temperature of about 180 to 200°C). (Heat-treated for 30 minutes.) At times, the resin melts and flows out from the punched area, blocking the punching area and hindering post-processing, and the resin shrinks greatly during the cooling and solidification process, so it is especially difficult to use the sheared area. The fact is that baked-on paint cannot be used for parts that will undergo a painting process because of the drawbacks such as deformation of the surrounding area.

The present inventors previously attempted to solve the above-mentioned problems regarding metal/polypropylene laminated composites by heat-pressing a metal plate on both sides of a sheet made of crystalline polypropylene mixed with a specific amount of waste paper via a modified polypropylene layer. However, in this laminated composite, the heat resistance of the modified polypropylene layer is still insufficient, so baking occurs when the modified polypropylene layer is softened during painting, reducing its adhesion to the metal surface, and the cutting process is difficult. There was a phenomenon in which parts of the cutting part peeled off in the vicinity, and the cut part had to be folded back before use, which caused problems in terms of application.

The inventors of the present invention have further conducted intensive studies to prevent the peeling phenomenon between the modified polypropylene layer and the metal surface during high-temperature treatment.As a result, we have developed a modified polypropylene layer in which crystalline polypropylene is modified with an unsaturated carboxylic acid or a derivative thereof. Alternatively, by using a polypropylene sheet made of crystalline polypropylene containing modified polypropylene mixed with a specific amount of waste paper as the core material, adhesive strength that can withstand secondary processing such as folding, punching, cutting, and deep drawing is achieved. In addition, during the painting process, there is no flow of molten resin or dripping of molten resin (hereinafter referred to as dripping) from the cut or punched parts during the processing process, and there is no heat around the cut or punched parts. It was discovered that a metal/polypropylene laminated composite that does not deform and does not peel off at the resin-metal interface can be obtained, and based on this knowledge, the present invention was completed.

As is clear from the above description, the purpose of the present invention is to have a high adhesive strength, prevent baking during painting, prevent molten resin from flowing out or falling off during the processing process, and prevent heat generation near the cut portion. An object of the present invention is to provide a metal/polypropylene laminated composite with excellent heat resistance that does not cause deformation or peeling between a resin and a metal plate.

(Failure to solve the problem) The present invention has the following configuration.

Modified polypropylene obtained by modifying crystalline polypropylene with an unsaturated carboxylic acid or a derivative thereof, or crystalline polypropylene containing modified polypropylene with waste paper 15-5
A metal/polypropylene laminated composite made by laminating metal plates on both sides of a polypropylene sheet containing 0% by weight and heat-pressing them.

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 the unsaturated carboxylic acids used in the production of the modified polypropylene include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, and phosphoric acid. In addition, derivatives of unsaturated carboxylic acids include acid anhydrides, esters, amides, imides, metal salts, etc.
For example, maleic anhydride, citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate,
Butyl methacrylate, glycidyl acrylate, methacrylate, glycidyl luate, monoethyl maleate, diethyl maleate, monomethyl 7-malate, dimethyl 7-malate, monomethyl itaconate, diethyl itaconate, acrylamide, methacryl amide, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, luic acid-N.

N-diethylamide, maleimide, N-butylmaleimide, N-phenylmaleimide, sodium acrylate,
Examples include sodium methacrylate, potassium acrylate, and the like.

Among these, 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. Further, in the present invention, a mixture of unmodified crystalline polypropylene containing 5% by weight or more of the above-mentioned modified polypropylene can be used. Generally, it is preferable to use a modified polypropylene containing an unsaturated carboxylic acid or a derivative thereof in an amount of 0.1 to 10% by weight, 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 a propylene homopolymer, a propylene-ethylene block copolymer containing at least 70ii% or more of a propylene component, and a random copolymer. , propylene-ethylene-butene-1 block copolymers and random copolymers, propylene-butene-1 random copolymers, and mixtures of two or more thereof. The crystalline polypropylene resin for modified polypropylene and the crystalline polypropylene used by mixing with the modified polypropylene may be of the same type or may be of different types. Further, the melt flow rate is preferably about 0.1 to 20 f/10 minutes, more preferably 0.5 to 10 f/10 minutes. In addition, the modified polypropylene used in the present invention or the crystalline polypropylene containing the modified polypropylene may contain other polyolefins, such as ethylene propylene rubber, ethylene propylene diene rubber, poly 4-methylpentene, ethylene acetic acid, within a range that does not impair the effects of the invention. It is also possible to use a mixture of vinyl copolymers and the like.

The waste paper used in the present invention is not limited in percentage as long as it is #1 paper such as newspaper, cardboard, cardboard paper, end posts of cardboard board, etc., and it is preferable to use paper that is inexpensive and available in large quantities. Moreover, it is preferable to use waste paper that has been shredded or coarsely crushed to a size of usually 3QNM or less, preferably 51u or less.

The content of the waste paper is preferably within the range of 15 to 50"xit-%, and particularly preferably 20 to 40% by weight. If the content of the waste paper exceeds 50% by weight, the resin flow during melting. This is not preferable because it not only significantly reduces the properties and makes molding difficult, but also reduces the adhesive strength of the laminated composite when it is made into a laminated composite. This is undesirable because the molten resin sometimes flows out from the cut or punched parts, and the interface between the resin and the metal plate easily peels off.

The polypropylene sheet used for the core material of the present invention contains heat-resistant stabilizers, weather-resistant stabilizers, etc. within the range that does not impair its functions.
The sheet may contain a lubricant, a slip agent, a flame retardant, an antistatic agent, a nucleating agent, an inorganic filler, etc.

The polypropylene sheet used for the core material of the present invention is formed into a sheet shape by a conventionally known method, and the thickness is 0.
．． It is desirable that it be in the range of 1 to 5 MM, preferably 0.2 to 2 MM.

Further, the metal plate used in the present invention may be a metal such as iron, steel, aluminum, copper, zinc, tin, nickel, titanium, or an alloy containing one or more of these as a main component. The thickness of the metal plate that can be made is 0.0
5-2M, preferably 0.15-1.0 cod. #Metal plates are usually used after the adhesive surface has been subjected to a surface treatment such as degreasing or sandblasting. Furthermore, a primer treatment such as an epoxy resin coating may be applied.

The laminated composite of the present invention can be obtained by superimposing metal plates whose adhesive surfaces have been surface-treated on both sides of the polypropylene sheet, and then heat-pressing them using a compression molding machine, a hot roll, or the like. The heating temperature at this time is 160~2
The temperature is preferably 20°C, the pressure is preferably within the range of 1 to 50 to 9/C11G, and it is desirable that the pressure bonding be carried out for 0.1 seconds to 10 minutes under such conditions.

(Effect of the invention) The laminated composite obtained by the present invention can be processed by cutting, punching,
It does not peel off even during secondary processing such as bending or deep drawing, and there is no molten resin flowing out from the cut surface of the cut or punched part during the coating process, and there is no dropout. In addition to extremely little deformation due to heat, there is no peeling phenomenon between the metal plate and the core material at the cut portion. Therefore, the interior and exterior panels of automobiles,
It can be suitably used in a wide range of applications, including various panels for home appliances and light electrical appliances, and architectural panels.

(Examples) Hereinafter, the present invention will be explained in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Examples 1 to 3, Comparative Examples 1 to 5) 1.3-bis(t
- 25% by weight of modified polypropylene modified with 1.2% by weight of maleic anhydride using 0.10% by weight of (butylperoxyisopropyl) benzene, 60% by weight of unmodified crystalline propylene homopolymer and ethylene propylene rubber. 15% by weight of polypropylene as a filler, waste paper cut into 5 pieces vertically and horizontally was placed in a Hensel mixer (trade name) in the ratio shown in Table 1 below, stirred and mixed for 3 minutes, and then the mixture was Extruded using a 65fl extruder with a T-die at a resin temperature of 210°C to a thickness of 9.4 III
! A sheet was formed.

In addition, as Comparative Examples 1 to 5, various fillers were blended with the polypropylene used in Examples 1 to 3 in the proportions shown in Table 1 below, mixed with stirring according to Examples 1 to 3, and extruded. A sheet with a thickness of 0.4 mm was obtained.

Next, as a metal plate, the surface was cleaned with a cleaning solution to a thickness of 0.2
A 7 m cold rolled steel plate was prepared.

The sheet was inserted between two steel plates and pressed together at 200° C. for 1 minute at a pressure of 201 g/cjG to obtain a laminated composite.

The T-peel strength and the state after heat treatment of the laminated composite were evaluated and observed, and the results are shown in Table 1. Note that the T-peel strength was measured in accordance with JIS K 6854. However, the tensile speed was 200 H/min.

In addition, for heat treatment, a test piece was prepared by drilling a hole with a diameter of 20 pieces in the center of a laminated composite that was cut into 20 cN5 length and 10 ffi width, and the core test piece was suspended for 30 minutes in a heated open chamber kept at 200°C. It was carried out.

As shown in Table 1, the laminated composite of the present invention in which a specific proportion of waste paper is blended into the core material has high peel strength, no flow of molten resin from the cut part due to heat treatment, and no deformation of the cut part. There are also extremely few.

Further, no peeling phenomenon between the metal plate and the resin 1- was observed at the cut portion, and the laminated composite maintained its shape before the heat treatment.

C Comparative Example 6] 1.3-bis(
t-Butylperoxyisopropyl)benzene 0.05
25% by weight of modified polypropylene obtained by modifying with 0.8% by weight of maleic anhydride and ethylene-containing T8.
5% by weight propylene-ethylene block copolymer 63
% by weight and 12% by weight of ethylene/propylene rubber were stirred and mixed for 3 minutes using a Hensel mixer (trade name), and then the mixture was melt-kneaded and extruded at a resin temperature of 200°C using an extruder with a T-die having a diameter of 4QNIl. A modified polypropylene film having a thickness of 40 μm was prepared.

Next, the crystalline propylene homopolymer and waste paper used as a filler were cut into 5 MH in each length and width. ii% was placed in a Hensel mixer (trade name) and stirred and mixed for 3 minutes, and then the mixture was heated to a resin temperature of 21% using an extruder with a T-die having a diameter of 65 mm.
A polypropylene sheet with an extrusion thickness of 0.32 JI was molded at 0°C.

Moreover, the same metal plate as that used in Examples 1 to 3 was prepared.

Each material was laminated in the order of steel plate/modified polypropylene film/polypropylene sheet/modified polypropylene film/steel plate and pressed together at 200° C. for 1 minute at a pressure of 20 kg and 7 ciG to form a laminated composite.

Regarding the laminated composites, the T-peel strength was measured and the state after heat treatment was observed in accordance with Examples 1 to 3. As a result, the T-peel strength was at a high level of 20.8 kq/251 Eif, and no resin flow was observed after heat treatment, but the metal plate and adhesive layer were peeled off in some parts of the cut section. confirmed.

Claims (1)

[Claims] Modified polypropylene obtained by modifying crystalline polypropylene with an unsaturated carboxylic acid or a derivative thereof, or crystalline polypropylene containing modified polypropylene with waste paper 15-5
A metal/polypropylene laminated composite made by laminating metal plates on both sides of a polypropylene sheet containing 0% by weight and heat-pressing them.