JPH0543741B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive polyethylene composition, and relates to a composition made of modified polyethylene that has excellent adhesive properties and various mechanical properties. It is well known to produce modified polyolefins by grafting unsaturated carboxylic acids onto polyolefins such as polyethylene and polypropylene.
These modified polyolefins are used to bond polyolefins with metals, polar resins, etc. by utilizing their adhesive properties, and are used for applications such as coatings and laminated films, and can also be mixed with glass fibers and inorganic fillers. It is used to improve the physical properties of filling compositions. It is known to use a mixture of polyethylenes instead of a single polyethylene component; for example, in Japanese Patent Publications No. 57-14707 and No. 52-32654, there is a method of mixing polyethylene components with different polymerization methods, and using modified polyethylene. and unmodified polyethylene, and in JP-A-54-82 and JP-A-54-83, a mixture of a crystalline polyethylene component and a low-crystalline ethylene/α-olefin copolymer component is described. A modified polyethylene is described.
However, as a result of further intensive research, the present inventors discovered that extremely excellent adhesiveness could be obtained by using polyethylene having a specific structure, and arrived at the present invention. The copolymer (A) used in the present invention is characterized by its molecular weight distribution and melt index falling within a specific range, and by using a copolymer within this range, the properties as an adhesive resin composition can be improved. be made stronger. That is, the density is 0.910 g/cm ³ or more and the molecular weight distribution is determined by gel permeation chromatography.
Mw/Mn value is 8 or more, ASTM D 1238
-57T, the ratio HLMI/MI of melt index at 190° C. load of 21.6 kg and melt index of 2.16 kg (g/10 min) is 45 or more. MI is preferably 0.05-50, particularly 0.1-20. When the molecular weight distribution becomes narrow and becomes less than the above value, the moldability decreases, the amount of extrusion molding decreases, and surface roughness during film molding tends to occur, which is not preferable, and the adhesiveness is also poor. Such a copolymer (A) can be obtained by carrying out a multi-stage polymerization reaction of two or more stages. usually,
The second stage of polymerization is carried out in the presence of the polymer obtained in the first stage by two-stage polymerization: a polymerization stage to obtain a relatively high molecular weight polymer and a polymerization stage to obtain a relatively low molecular weight polymer. Manufactured by In particular, it is preferable to manufacture by slurry polymerization using a catalyst containing magnesium and titanium. The relatively high molecular weight polymer preferably has a viscosity average molecular weight of 150,000 to 1,000,000, and the low molecular weight polymer preferably has a viscosity average molecular weight of 10,000 to 80,000.
It is preferable that each polymer is contained in a weight ratio of 3 to 7:7 to 3. The low molecular weight polymer may be an ethylene homopolymer, and the α-olefin content in the high molecular weight polymer is at least 1.5 times, particularly at least 2 times, the α-olefin content in the low molecular weight polymer. It is preferable that there be. As the α-olefin, butene-1, hexane-1, 4-methylpentene-1, octene-1, etc. are preferably used. If the α-olefin content of the low molecular weight polymer and the high molecular weight polymer are relatively similar, a decrease in adhesive strength and a decrease in moldability occur. Such polyethylene can be produced by various known methods. For example, JP-A-56-22304,
Multi-stage polymerization may be carried out according to the methods of 56-10506 and 56-164205. In addition, regardless of such multi-stage polymerization, the molecular weight,
Although it is possible to obtain individual polyethylenes with different comonomer contents and blend them, problems such as formation of fibers due to non-uniform mixing are likely to occur, so multi-stage polymerization is preferable. Copolymer (B) can be obtained by copolymerizing ethylene, α-olefin, and optionally dienes according to a known method. Density is a characteristic
It is soft with a weight of 0.910 g/cm ³ or less, and has a degree of crystal resolution of 30% or less as measured by an X-ray method. α
-Olefin may be any propylene, butene-1, hexane-1, etc., and a multi-component copolymer of ethylene, α-olefin and diene compound, commonly known as EPDM, may also be used. The copolymer (A) and the rigid copolymer (B) can be mixed by a conventional method. For example, they can be melt-kneaded using a Banbury mixer, an extruder, or the like. The blend ratio is 3 to 50 parts by weight of copolymer (B) to 50 to 97 parts by weight of copolymer (A), and if the proportion of copolymer (B) exceeds 50 parts by weight, The properties of the copolymer (A) are lost, and even if it is less than 3 parts by weight, the effect of adding the copolymer (B) is reduced, which is not desirable. Examples of unsaturated carboxylic acids include α- and β-unsaturated carboxylic acids such as maleic acid, acrylic acid, and methacrylic acid, and alicyclic polyhydric carboxylic acids having an unsaturated bond in the ring. A substance, admi, ester, etc. can be used. Among these, maleic acid, acrylic acid and derivatives thereof are preferred, and maleic anhydride is particularly preferred. The amount of unsaturated carboxylic acid added is 0.001 to 10 wt% with respect to the composition consisting of copolymer (A) and copolymer (B),
Preferably 0.01-5wt%, more preferably 0.05
~1wt%. If the amount of added carboxylic acid is small, the adhesiveness will be poor, and if the amount added is too large, problems such as coloring will occur, which is not only undesirable, but also the adhesive strength will not increase, so no effect can be expected. Addition of unsaturated carboxylic acids can be carried out by conventionally known methods. Although the melt-kneading method is economically preferred, it goes without saying that various conventionally improved methods may also be used. In the present invention, at least one of the copolymers (A) and (B) may be modified polyethylene to which an unsaturated carboxylic acid has been added, but copolymers (B) alone or copolymers may be used. Preferably, both coalesce (A) and (B) are modified. Therefore, a method of graft-modifying part or all of one of copolymers (A) or (B) and mixing it with the other, a method of graft-modifying part or all of a mixture of copolymers (A) and (B), The composition of the present invention can be produced by various grafting reactions or blending methods such as modification methods. The adhesive polyethylene composition of the present invention takes advantage of its high adhesiveness, good moldability, and physical properties to
It can be used for adhesion with metals such as aluminum, and for manufacturing laminated films, containers, etc. with various materials such as nylon resin, polyester resin, ethylene vinyl alcohol copolymer resin, paper, and cellophane. Furthermore, by taking advantage of its adhesive properties with glass fibers and fillers such as calcium carbonate, it can be used in filler-containing polyolefins to improve physical properties such as impact resistance. Further, when using the modified polyolefin of the present invention, conventional additives such as fillers, various stabilizers, anti-slip agents, etc. can be added. Next, the present invention will be explained in more detail with reference to Examples. Examples 1 to 8, Comparative Examples 1 to 3 (Production of copolymer (A)) Diethoxymagnesium, tributoxytitanium monochloride, and butanol were mixed and heated in a ratio of 2:1:1, and the resulting homogeneous mixture was heated. , a catalyst containing magnesium and titanium components was prepared by reacting 2.5 molar amounts of ethylaluminum sesquichloride. Using this catalyst component and triethylaluminum as a cocatalyst, a relatively large amount of hydrogen and a small amount of butene-1 are supplied together with ethylene in a reaction temperature of 90° C. in normal hexane as a first step.
The low molecular weight components were polymerized and the high molecular weight components were polymerized in the second step by supplying a relatively small amount of hydrogen and a relatively large amount of butene-1. MI, HLMI/MI was determined from the melt index of the obtained polymer, gel permeation chromatography measurement results, infrared spectroscopic analysis values, and analysis of polymerization conditions.
The ratio, comonomer content ratio, Mw/Mn ratio, etc. were determined. The measured values and analytical values are shown in Table-1. (Production of copolymer (B)) Ethylene and butene-1 were copolymerized at a polymerization temperature of 135°C using vanadium oxytrichloride and diethylaluminium monochloride as catalysts, resulting in a melt index of 3.5, a density of 0.89, and an X-ray A copolymer (B) with a crystallinity of 20% was obtained by the method. As for ethylene propylene rubber (Example 8), a commercially available product was used. (Modification of copolymer) Copolymer (A) and/or copolymer (B) were mixed with a predetermined amount of maleic anhydride and α,α-diterthi-butylperoxyparaisopropylbenzene, and the inner diameter was 30 mmφ. , using a single screw extruder with L/D=24
The copolymer was modified by melt-kneading and grafting at 210°C. The grafting rate was determined by infrared spectroscopy after removing unreacted monomers by acetone extraction. (Manufacture of adhesive polyethylene composition) When grafted onto a mixture of copolymers (A) and (B), the physical properties are evaluated as an adhesive polyethylene composition as is, and when only one is modified, it is compared with the other. The mixture was mixed and kneaded using an extruder to obtain an adhesive polyethylene composition. Measurement of adhesive strength in composite film Modified polyethylene composition and ethylene vinyl alcohol copolymer resin (ethylene content 39 mol%, degree of saponification approximately 100%, melt index 8 at 210°C) were coextruded in a die. A composite inflation film was prepared in which the inner layer was made of an adhesive polyethylene composition and the outer layer was made of an ethylene vinyl alcohol resin. Die inner diameter 80mmφ, die temperature 210℃
Polyolefin composition side extruder L/D=24, temperature
Coextrusion was carried out at 210°C, ethylene vinyl alcohol resin side extruder L/D = 20, and temperature of 210°C. The winding speed is 3.1 m/mm, the blow-up ratio is 2, the thickness of ethylene vinyl alcohol resin is 100μ, and the thickness of modified polyethylene is 100μ. The T peel strength of this composite film is determined by JIS K 6854.
Measured according to. The results are shown in Table-1. Measurement of adhesive strength in metal plate laminates The surface of a steel plate (10 mm thick) was blast-treated with 0.3 mm steel grit, heated to approximately 140°C in a heating furnace, and then bonded with the post-adhesive polyethylene composition and high density. A laminate of a steel plate and polyethylene was produced by laminating a two-layer molten sheet of polyethylene (adhesive polyethylene composition 400μ, high density polyethylene 4mm, resin temperature 230°C). After the obtained laminate was cooled to room temperature, the adhesive strength of the laminate was evaluated. Adhesive strength was measured using a conventional method at a peeling speed of 10 mm/min.
Measured using a 90° peel test. The results are shown in Table-1. 【table】

Claims (1)

[Claims] 1 Ethylene and α-olefin having 3 or more carbon atoms are polymerized in multiple steps including a polymerization step to obtain a relatively high molecular weight polymer and a polymerization step to obtain a relatively low molecular weight polymer. The α-olefin content of the molecular weight polymer is 1.5 times or more than the α-olefin content of the low molecular weight polymer, the density is 0.910 g/cm ³ or more, the melt index (MI ) 0.1 to 50, the ratio of melt index (MLMI) at 190℃ and 21.6 kg load to the above melt index (CHLMI) and (HLMI/
MI) 45 or higher and molecular weight distribution (Mw/
Copolymer (A) with 50 to 97 parts by weight of Mn) 8 or more, ethylene with a density of 0.910 g/cm ³ or less, and a crystallinity of 30% or less as measured by X-ray method, and a copolymer with a carbon number of 3 or more. A composition comprising 3 to 50 parts by weight of a copolymer (B) containing an α-olefin and optionally a diene, wherein at least one of the copolymer (A) and the copolymer (B) is added to the composition. An adhesive polyethylene composition characterized in that it has been modified with 0.001 to 10% by weight of an unsaturated carboxylic acid or a derivative thereof.